feat(eda): capítulo MISSINGNESS — patrones de datos faltantes (co-ocurrencia + MCAR/MAR)

Añade el capítulo `missingness` al motor AutomaticEDA, complemento natural de
`calidad`: donde calidad reporta cuánto falta por columna, este capítulo analiza
el PATRÓN de los nulos — dónde faltan y si las columnas faltan juntas
(co-ocurrencia de ausencias), la señal que distingue MCAR de MAR antes de imputar.

Capítulo (`chapters/missingness.py`), registrado en `chapters_registry.py` justo
tras `calidad`:
- Resumen global: % de celdas faltantes, columnas con nulos, filas completas vs
  incompletas.
- Ranking por columna (tabla + barras horizontales).
- Co-ocurrencia: correlación de las máscaras is-null entre columnas (heatmap +
  tabla de los pares que co-faltan, con co-faltantes y Jaccard).
- Patrones de fila más frecuentes (estilo matriz de missingno).
- Lectura MCAR/MAR exploratoria (heurística por correlación/solape de ausencias,
  no confirmatoria), que cita la evidencia concreta.
- Términos de glosario clicables: missingness, MCAR, MAR.

La máscara is-null por fila de TODAS las columnas (numéricas y categóricas) se
construye con un push-down DuckDB sobre ctx['db_path']/table (mismo patrón que el
capítulo agregación), con fallback a ctx['raw_numeric'] cuando no hay BD. Activa
solo si la tabla tiene nulos; si no, devuelve None.

Funciones nuevas del grupo `eda` (dominio datascience):
- extract_null_mask (impura): máscara is-null por fila vía query_fn.
- missingness_overview (pura): resumen global + filas completas/incompletas.
- missingness_correlation (pura): correlación de ausencias + pares + Jaccard,
  reutiliza pearson.
- missingness_row_patterns (pura): patrones de fila más comunes.
- missingness_corr_heatmap_figure / missingness_rank_bar_figure (impuras): figuras.

Verificado: EDA de titanic genera el capítulo en PDF + PPTX + MD con Cabin 77.1%,
Age 19.9% y la co-ocurrencia Age↔Cabin (158 filas). Suite completa de AutomaticEDA
+ render_automatic_eda en verde (125 passed); tests por función y por capítulo;
fn index sin error.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

python/functions/datascience/__init__.py

@@ -64,6 +64,7 @@ from .exploratory_caveats import exploratory_caveats
 from .render_eda_pdf import render_eda_pdf, render_eda_pdf_relational
 from .render_automatic_eda_pdf import render_automatic_eda_pdf
 from .render_automatic_eda_pptx import render_automatic_eda_pptx
+from .render_automatic_eda_markdown import render_automatic_eda_markdown
 from .detect_time_column import detect_time_column
 from .extract_timeseries_raw import extract_timeseries_raw
 from .build_eda_render_ctx import build_eda_render_ctx
@@ -82,6 +83,7 @@ __all__ = [
     "resample_timeseries",
     "render_automatic_eda_pdf",
     "render_automatic_eda_pptx",
+    "render_automatic_eda_markdown",
     "decode_qr_image",
     "adf_kpss_stationarity",
     "acf_pacf",

python/functions/datascience/automatic_eda/__init__.py

@@ -36,6 +36,7 @@ from .model import (  # noqa: F401
 from .chapters_registry import CHAPTER_ORDER, build_chapter, build_document  # noqa: F401
 from .render_pdf_impl import render_pdf  # noqa: F401
 from .render_pptx_impl import render_pptx  # noqa: F401
+from .render_md_impl import render_md  # noqa: F401
 
 __all__ = [
     "ENGINE_NAME",
@@ -60,4 +61,5 @@ __all__ = [
     "build_document",
     "render_pdf",
     "render_pptx",
+    "render_md",
 ]

python/functions/datascience/automatic_eda/chapters/cat_distr.py

@@ -1,19 +1,25 @@
 """Categorical distributions chapter (CAT DISTR).
 
-Third reference chapter for AutomaticEDA. For every categorical column it shows,
-fulfilling the user's request:
+Third reference chapter for AutomaticEDA. Each categorical column gets **its own
+page (PDF) / slide (PPTX)**: every column is wrapped in a keep-together
+``model.Group`` with ``page_break_before=True`` (except the first, which may share
+the intro's page), so its chart sits next to its tables and no column is split.
 
-1. A short opening explanation of **Shannon entropy** (what it measures, its 0
-   and log2(k) bounds, the normalized 0–1 version) and the dataset row total used
-   as a comparison baseline.
-2. Per column, a cardinality key/value table: distinct values, ``% distinct``
-   (distinct / total rows), total dataset rows, singleton values (frequency 1),
-   entropy with its theoretical maximum and the normalized ratio, mode, imbalance
-   and string-length stats.
-3. A short note flagging problematic cardinality (id-like ≈100% distinct, or a
+A short intro names the clickable **[[term:entropia]]entropía[[/term]]** term —
+the full definition lives in the GLOSARIO chapter, so it is NOT repeated inline
+here (one click jumps to the glossary entry). The intro also carries the dataset
+row total used as a comparison baseline.
+
+Per column the Group contains, in order:
+
+1. A cardinality key/value table: distinct values, ``% distinct`` (distinct /
+   total rows), total dataset rows, singleton values (frequency 1), entropy with
+   its theoretical maximum and the normalized ratio, mode, imbalance and
+   string-length stats.
+2. A short note flagging problematic cardinality (id-like ≈100% distinct, or a
    single dominating category).
-4. A ``top-k`` table (value / count / %).
-5. A **donut pie chart** of the most common categories (top-k + an "Otros"
+3. A ``top-k`` table (value / count / %).
+4. A **donut pie chart** of the most common categories (top-k + an "Otros"
    bucket), drawn lazily so the renderers scale it to fit entirely.
 
 Data comes from the ``eda`` group: each ``columns[i]['categorical']`` is the
@@ -33,7 +39,7 @@ import math
 
 from .. import model
 
-CHAPTER_VERSION = "1.1.0"
+CHAPTER_VERSION = "1.2.0"
 CHAPTER_ID = "cat_distr"
 CHAPTER_TITLE = "Distribuciones categóricas"
 
@@ -53,11 +59,17 @@ _TERM_ENTROPIA_DEF = (
 # Cap the number of categorical columns rendered to keep the document bounded;
 # the rest are summarized in a closing note (no silent truncation).
 MAX_COLS = 40
-# Rows shown in each top-k table and explicit slices in the pie.
-TOP_TABLE_ROWS = 15
+# Rows shown in each top-k table and explicit slices in the pie. Kept moderate so
+# the whole column — cardinality table + top-k table + donut — fits on ONE
+# page/slide with the chart next to its tables; the table note still reports
+# "top N of M" so nothing is silently hidden. For id-like columns (≈100%
+# distinct) the top-k table is dropped entirely (it would be a list of unique
+# values — pure noise), which also frees the room the donut needs (see build).
+TOP_TABLE_ROWS = 8
 PIE_TOP_K = 6
-# Truncate very long category labels in tables (the renderer also wraps).
-LABEL_MAX = 48
+# Truncate very long category labels in tables (the renderer also wraps). Kept
+# tight so a column with long id-like values (names, tickets) still fits its page.
+LABEL_MAX = 28
 
 
 def _fmt_int(value) -> str:
@@ -267,45 +279,55 @@ def _normalize_card(card: dict) -> dict:
 
 
 def _cardinality_block(card: dict):
-    """KVTable with the cardinality / entropy metrics for one column."""
+    """KVTable with the cardinality / entropy metrics for one column.
+
+    Related metrics are grouped onto a single row each (distinct/%/unique;
+    entropy bits/max/normalized; length min/mean/max) so the whole column —
+    table + chart — fits one page/slide without dropping any datum; the short
+    16:9 PPTX slide does not fit one metric per row plus a chart otherwise."""
     n_singletons = card.get("n_singletons")
     if n_singletons is not None and card.get("n_singletons_partial"):
-        singletons = f"≥{_fmt_int(n_singletons)} (en top mostrado)"
+        singletons = f"≥{_fmt_int(n_singletons)}"
     elif n_singletons is not None:
         singletons = _fmt_int(n_singletons)
     else:
         singletons = "—"
 
-    entropy_ref = _fmt_num(card.get("entropy"))
-    emax = card.get("entropy_max")
-    if emax is not None:
-        entropy_ref = f"{entropy_ref} (máx {_fmt_num(emax)})"
+    # Distinct count · % distinct · unique (frequency 1) on one row.
+    distinct_combo = (f"{_fmt_int(card.get('n_distinct'))} · "
+                      f"{_fmt_pct_value(card.get('pct_distinct'))} · "
+                      f"{singletons} únicos")
+
+    # Entropy bits · theoretical max · normalized 0–1 on one row.
+    entropy_combo = (f"{_fmt_num(card.get('entropy'))} bits · "
+                     f"máx {_fmt_num(card.get('entropy_max'))} · "
+                     f"norm {_fmt_num(card.get('entropy_norm'))}")
 
     mode = card.get("mode")
     mode_pct = card.get("mode_pct")
-    mode_str = "—" if mode is None else model._safe_str(mode)
+    mode_str = "—" if mode is None else _truncate(mode, 32)
     if mode is not None and mode_pct is not None:
         mode_str = f"{mode_str} ({_fmt_pct_value(mode_pct)})"
 
     rows = [
-        ("Valores distintos", _fmt_int(card.get("n_distinct"))),
-        ("% distintos", _fmt_pct_value(card.get("pct_distinct"))),
+        ("Distintos · % · únicos", distinct_combo),
         ("Total filas (dataset)", _fmt_int(card.get("n_rows"))),
-        ("Valores únicos (frecuencia 1)", singletons),
-        ("Entropía (bits)", entropy_ref),
-        ("Entropía normalizada (0–1)", _fmt_num(card.get("entropy_norm"))),
+        ("Entropía (bits · máx · norm)", entropy_combo),
         ("Moda", mode_str),
     ]
     imbalance = card.get("imbalance")
-    if imbalance is not None:
-        rows.append(("Desbalance", _fmt_num(imbalance)))
     lm = card.get("len_min")
     lmean = card.get("len_mean")
     lmax = card.get("len_max")
+    # Imbalance and string length (both secondary) share one closing row.
+    extras = []
+    if imbalance is not None:
+        extras.append(f"desbalance {_fmt_num(imbalance)}")
     if any(v is not None for v in (lm, lmean, lmax)):
-        rows.append((
-            "Longitud (mín/media/máx)",
-            f"{_fmt_num(lm)} / {_fmt_num(lmean)} / {_fmt_num(lmax)}"))
+        extras.append(
+            f"long. {_fmt_num(lm)}/{_fmt_num(lmean)}/{_fmt_num(lmax)}")
+    if extras:
+        rows.append(("Desbalance · longitud", " · ".join(extras)))
     return model.KVTable(rows=rows, title="Cardinalidad")
 
 
@@ -315,7 +337,8 @@ def _flag_note(card: dict):
         return model.Note(
             "Casi todos los valores son distintos (≈100% distintos): la columna "
             "se comporta como un identificador y aporta poco para agrupar o "
-            "comparar categorías.")
+            "comparar categorías. No se lista el top de categorías (serían "
+            "valores casi todos únicos).")
     if card.get("dominated"):
         mp = card.get("mode_pct")
         mp_str = _fmt_pct_value(mp) if mp is not None else "muy alta"
@@ -335,7 +358,7 @@ def _topk_table(cat: dict):
         if not isinstance(t, dict):
             continue
         rows.append([
-            model._safe_str(t.get("value")),
+            _truncate(t.get("value")),
             _fmt_int(t.get("count")),
             _pct_from_maybe_fraction(t.get("pct")),
         ])
@@ -353,20 +376,16 @@ def _topk_table(cat: dict):
 def _intro_blocks(n_rows, mark_term: bool = False):
     total = _fmt_int(n_rows)
     # Mark the first appearance of the term as a clickable glossary jump when the
-    # term was registered (mark_term). The visible text is identical either way.
-    entropia = ("[[term:entropia]]**entropía de Shannon**[[/term]]" if mark_term
-                else "**entropía de Shannon**")
+    # term was registered (mark_term). The full definition of entropy lives in the
+    # GLOSARIO chapter, so the intro only names the clickable term here instead of
+    # repeating the long explanation (avoids the redundancy with the glossary).
+    entropia = ("[[term:entropia]]entropía[[/term]]" if mark_term
+                else "entropía")
     text = (
-        f"La {entropia} mide cómo de repartidos están los valores de "
-        "una columna categórica, en bits. Vale 0 cuando una sola categoría "
-        "concentra todas las filas (máxima previsibilidad) y alcanza su máximo, "
-        "log2(k) para k categorías distintas, cuando todas aparecen por igual "
-        "(máxima diversidad). La **entropía normalizada** (entropía dividida por "
-        "su máximo) la lleva al rango 0–1 para comparar columnas con distinto "
-        "número de categorías. Para cada columna se muestran los valores "
-        "distintos, el porcentaje que representan sobre el total de filas, los "
-        "valores únicos (que aparecen una sola vez), la tabla de las categorías "
-        "más frecuentes y un gráfico de tarta (donut) de las más comunes."
+        f"Cada columna categórica ocupa su propia página: sus métricas de "
+        f"cardinalidad —incluida la {entropia}—, una nota que señala cardinalidad "
+        "problemática, la tabla de las categorías más frecuentes y un gráfico de "
+        "tarta (donut) de las más comunes, todo junto."
     )
     if n_rows is not None:
         text += f" El dataset tiene {total} filas en total como referencia."
@@ -398,24 +417,37 @@ def build_cat_distr(profile: dict, ctx: dict):
     blocks = list(_intro_blocks(n_rows, mark_term=mark_term))
 
     rendered = cat_cols[:MAX_COLS]
-    for col in rendered:
+    for idx, col in enumerate(rendered):
         name = col.get("name") or "(columna)"
         cat = col.get("categorical") or {}
         card = _normalize_card(_cardinality(cat, n_rows))
 
-        blocks.append(model.Heading(text=str(name), level=2))
-        blocks.append(_cardinality_block(card))
+        # One Group per categorical column: heading + cardinality table + flag
+        # note + top-k table + donut figure are kept together and the renderer
+        # starts each on a fresh page/slide (page_break_before) so every column
+        # gets its own page with its chart next to its tables. The first column
+        # may share the intro's page (no forced break) to avoid a near-empty page.
+        col_blocks = [
+            model.Heading(text=str(name), level=2),
+            _cardinality_block(card),
+        ]
         note = _flag_note(card)
         if note is not None:
-            blocks.append(note)
-        topk = _topk_table(cat)
-        if topk is not None:
-            blocks.append(topk)
-        blocks.append(model.Figure(
+            col_blocks.append(note)
+        # For id-like columns (≈100% distinct) the top-k is a list of unique
+        # values — pure noise; skip it (the flag note already explains why) and
+        # let the donut take that room so the whole column fits one page/slide.
+        if not card.get("id_like"):
+            topk = _topk_table(cat)
+            if topk is not None:
+                col_blocks.append(topk)
+        col_blocks.append(model.Figure(
             make=_pie_make(cat.get("top") or [], card.get("n_distinct"),
                            str(name), n_rows),
             caption=(f"Categorías más comunes de «{_truncate(name, 32)}» "
                      "(donut: top-k + «Otros»)")))
+        blocks.append(model.Group(blocks=col_blocks,
+                                  page_break_before=(idx > 0)))
 
     if len(cat_cols) > len(rendered):
         omitted = len(cat_cols) - len(rendered)

python/functions/datascience/automatic_eda/chapters/cat_distr_test.py

@@ -2,11 +2,14 @@
 
 Self-contained: builds synthetic TableProfiles (no DuckDB) so the suite is fast
 and deterministic. Verifies that ``build_cat_distr`` emits the blocks the user
-asked for (entropy intro, distinct/total/%-distinct/unique metrics, top-k table
-and a donut figure), that the chapter renders inside the full document to both
-PDF and PPTX showing that content, that a profile with no categorical columns
-yields ``None`` without raising, and that long labels / many columns are never
-cut in either output.
+asked for (distinct/total/%-distinct/unique metrics, top-k table and a donut
+figure), that EACH categorical column is wrapped in its own keep-together
+``Group`` that starts on a fresh page/slide (one column per page, chart next to
+its tables), that the long entropy explanation is NOT repeated inline (it lives
+in the glossary — only the clickable term is kept), that the chapter renders
+inside the full document to both PDF and PPTX showing that content, that a
+profile with no categorical columns yields ``None`` without raising, and that
+long labels / many columns are never cut in either output.
 """
 
 import os
@@ -17,7 +20,8 @@ from pypdf import PdfReader
 from pptx import Presentation
 
 from datascience.automatic_eda.model import (
-    DataTable, Figure, Heading, KVTable, Note,
+    DataTable, Figure, GlossaryCollector, Group, Heading, KVTable, Markdown,
+    Note,
 )
 from datascience.automatic_eda.chapters.cat_distr import (
     CHAPTER_ID, CHAPTER_VERSION, build_cat_distr,
@@ -81,8 +85,20 @@ def _pptx_text(path: str) -> str:
     return re.sub(r"\s+", " ", " ".join(parts))
 
 
-def _kinds(chapter):
-    return [b.kind for b in chapter.blocks]
+def _flatten(blocks):
+    """Expand keep-together Groups so the per-column heading/table/figure are
+    inspectable as a flat block list (the chapter wraps each column in a Group)."""
+    out = []
+    for b in blocks:
+        if getattr(b, "kind", "") == "group":
+            out.extend(_flatten(getattr(b, "blocks", []) or []))
+        else:
+            out.append(b)
+    return out
+
+
+def _column_groups(chapter):
+    return [b for b in chapter.blocks if isinstance(b, Group)]
 
 
 def test_golden_build_cat_distr_emite_bloques_pedidos():
@@ -90,36 +106,101 @@ def test_golden_build_cat_distr_emite_bloques_pedidos():
     assert ch is not None
     assert ch.id == CHAPTER_ID
     assert ch.version == CHAPTER_VERSION
-    kinds = _kinds(ch)
-    # Entropy intro present.
+
+    # Entropy intro present, but the long explanation is gone (it lives in the
+    # glossary now): only the term is named, no log2/normalizada walkthrough.
     headings = [b.text for b in ch.blocks if isinstance(b, Heading)]
     assert any("Entrop" in h for h in headings)
-    md = next(b for b in ch.blocks if b.kind == "markdown")
-    assert "entropía" in md.text.lower() and "log2" in md.text
-    # Cardinality metrics: distinct, total rows, %-distinct, unique values.
-    kv = next(b for b in ch.blocks if isinstance(b, KVTable))
+    md = next(b for b in ch.blocks if isinstance(b, Markdown))
+    assert "entropía" in md.text.lower()
+    assert "log2" not in md.text          # redundant explanation removed.
+    assert "máxima diversidad" not in md.text
+
+    # Per-column blocks are wrapped in keep-together Groups: flatten to inspect.
+    flat = _flatten(ch.blocks)
+    kv = next(b for b in flat if isinstance(b, KVTable))
     labels = [r[0] for r in kv.rows]
-    assert "Valores distintos" in labels
-    assert "% distintos" in labels
+    values = " ".join(str(r[1]) for r in kv.rows)
+    # Cardinality metrics: distinct count, %-distinct, unique values and total
+    # rows are present (grouped onto compact rows so the chart fits the page).
+    assert "Distintos · % · únicos" in labels
     assert "Total filas (dataset)" in labels
-    assert "Valores únicos (frecuencia 1)" in labels
     assert any("Entropía" in lbl for lbl in labels)
+    assert "únicos" in values and "%" in values
+    assert "bits" in values and "norm" in values   # entropy + max + normalized.
     # Top-k table + pie figure.
-    dt = next(b for b in ch.blocks if isinstance(b, DataTable))
+    dt = next(b for b in flat if isinstance(b, DataTable))
     assert dt.header == ["Valor", "Conteo", "%"]
     assert any("neumaticos" in str(cell) for row in dt.rows for cell in row)
-    assert any(isinstance(b, Figure) for b in ch.blocks)
-    # id-like column flagged with a Note.
-    assert any(isinstance(b, Note) and "identificador" in b.text
-               for b in ch.blocks)
+    assert any(isinstance(b, Figure) for b in flat)
+    # id-like column flagged with a Note that also explains the top-k is dropped.
+    idnote = next((b for b in flat
+                   if isinstance(b, Note) and "identificador" in b.text), None)
+    assert idnote is not None
+    assert "No se lista el top" in idnote.text
 
 
-def test_golden_render_pdf_muestra_categoricas():
+def test_golden_idlike_omite_topk_y_conserva_donut():
+    # The id-like column (uuid, 100% distinct) must NOT carry a top-k DataTable
+    # (it would be a list of unique values), but must still keep its donut Figure
+    # and its cardinality table so it stays a full per-column page.
+    ch = build_cat_distr(_profile(), {})
+    groups = _column_groups(ch)
+    uuid_group = next(g for g in groups
+                      if any(getattr(b, "text", "") == "uuid" for b in g.blocks))
+    kinds = [b.kind for b in uuid_group.blocks]
+    assert "data_table" not in kinds      # top-k of unique values dropped.
+    assert "kv_table" in kinds            # cardinality kept.
+    assert "figure" in kinds              # donut kept (chart per column).
+    # A non-id-like column keeps its top-k table.
+    cat_group = next(g for g in groups
+                     if any(getattr(b, "text", "") == "categoria"
+                            for b in g.blocks))
+    assert "data_table" in [b.kind for b in cat_group.blocks]
+
+
+def test_golden_una_pagina_por_columna_groups():
+    ch = build_cat_distr(_profile(), {})
+    groups = _column_groups(ch)
+    # Two categorical columns -> two column Groups (numeric column excluded).
+    assert len(groups) == 2
+    # Each Group carries one column: a heading + its cardinality table + figure.
+    for g in groups:
+        kinds = [b.kind for b in g.blocks]
+        assert kinds[0] == "heading"
+        assert "kv_table" in kinds
+        assert "figure" in kinds
+    # The first column may share the intro page (no forced break); every later
+    # column starts on a fresh page/slide so each column gets its own page.
+    assert groups[0].page_break_before is False
+    assert all(g.page_break_before is True for g in groups[1:])
+
+
+def test_golden_entropia_clicable_y_definicion_en_glosario():
+    # With a glossary collector the intro marks the clickable term and the FULL
+    # definition (the long explanation removed from the intro) lands in the
+    # glossary, not inline — no data lost, just relocated.
+    gc = GlossaryCollector()
+    ch = build_cat_distr(_profile(), {"glossary": gc})
+    md = next(b for b in ch.blocks if isinstance(b, Markdown))
+    assert "[[term:entropia]]entropía[[/term]]" in md.text
+    assert gc.has("entropia")
+    entry = gc.get("entropia")
+    assert entry is not None
+    # The definition kept in the glossary still carries the detail removed inline.
+    assert "log2" in entry["definition"]
+    assert "normalizada" in entry["definition"].lower()
+
+
+def test_golden_render_pdf_una_pagina_por_columna():
     with tempfile.TemporaryDirectory() as d:
         out = os.path.join(d, "eda.pdf")
         res = render_automatic_eda_pdf(_profile(), out, {"title": "EDA"})
         assert res["path"] == out and os.path.exists(out)
-        assert CHAPTER_ID in [c["id"] for c in res["chapters"]]
+        cat_meta = next(c for c in res["chapters"] if c["id"] == CHAPTER_ID)
+        # Two categorical columns, each on its own page -> >= 2 pages for the
+        # chapter (intro shares the first column's page).
+        assert cat_meta["n_pages"] >= 2
         txt = _pdf_text(out)
         assert "Entrop" in txt
         assert "distintos" in txt
@@ -133,13 +214,91 @@ def test_golden_render_pptx_muestra_categoricas():
         out = os.path.join(d, "eda.pptx")
         res = render_automatic_eda_pptx(_profile(), out, {"title": "EDA"})
         assert res["path"] == out and os.path.exists(out)
-        assert CHAPTER_ID in [c["id"] for c in res["chapters"]]
+        cat_meta = next(c for c in res["chapters"] if c["id"] == CHAPTER_ID)
+        assert cat_meta["n_slides"] >= 2  # one slide per categorical column.
         txt = _pptx_text(out)
         assert "Entrop" in txt
         assert "categoria" in txt and "neumaticos" in txt
         assert "distintos" in txt
 
 
+def _profile_high_card() -> dict:
+    """Profile with a high-cardinality NON-id-like categorical column whose top-k
+    of long values would split from its donut on a short 16:9 slide unless the
+    renderer trims the table — the exact case the adversarial check flagged
+    (Ticket / Cabin)."""
+    long_vals = [f"Valor largo de categoria numero {i:02d} con texto extra"
+                 for i in range(40)]
+    top = [{"value": v, "count": 60 - i, "pct": (60 - i) / 5000.0}
+           for i, v in enumerate(long_vals)]
+    return {
+        "table": "t", "source": "t.csv", "n_rows": 5000, "n_cols": 3,
+        "quality_score": 80.0,
+        "columns": [
+            {"name": "precio", "inferred_type": "numeric", "null_pct": 0.0,
+             "numeric": {"mean": 1.0, "median": 1.0, "min": 0.0, "max": 2.0,
+                         "std": 0.5}},
+            # 40 distinct over 5000 rows = 0.8% distinct -> NOT id-like, keeps
+            # its (long) top-k table; the tall table must not push the donut off.
+            {"name": "alta_card_col", "inferred_type": "categorical",
+             "null_pct": 0.0, "distinct_count": 40,
+             "categorical": {"top": top, "mode": long_vals[0], "n_distinct": 40,
+                             "entropy": 5.2, "imbalance": 1.2, "len_min": 40,
+                             "len_mean": 45, "len_max": 50}},
+            {"name": "baja_card_col", "inferred_type": "categorical",
+             "null_pct": 0.0, "distinct_count": 4,
+             "categorical": {
+                 "top": [{"value": "norte", "count": 2000, "pct": 0.4},
+                         {"value": "sur", "count": 1500, "pct": 0.3},
+                         {"value": "este", "count": 1000, "pct": 0.2},
+                         {"value": "oeste", "count": 500, "pct": 0.1}],
+                 "mode": "norte", "n_distinct": 4, "entropy": 1.8}},
+        ],
+    }
+
+
+def test_golden_pptx_una_slide_por_columna_con_su_grafico():
+    """Each categorical column occupies EXACTLY ONE cat_distr slide that carries
+    BOTH its cardinality table and its donut figure (picture) — i.e. the chart is
+    never separated from its table, even for a high-cardinality column."""
+    from pptx.enum.shapes import MSO_SHAPE_TYPE
+
+    prof = _profile_high_card()
+    cat_names = ["alta_card_col", "baja_card_col"]
+    with tempfile.TemporaryDirectory() as d:
+        out = os.path.join(d, "eda.pptx")
+        res = render_automatic_eda_pptx(prof, out, {"title": "EDA"})
+        assert res["path"] == out and os.path.exists(out)
+        prs = Presentation(out)
+
+        # Per column: the cat_distr slides whose text mentions it, and whether the
+        # owning slide also has the donut caption + an actual picture shape.
+        slides_with_col = {n: [] for n in cat_names}
+        owner_has_chart = {n: False for n in cat_names}
+        for i, sl in enumerate(prs.slides):
+            texts, has_pic = [], False
+            for sh in sl.shapes:
+                if sh.has_text_frame:
+                    texts.append(sh.text_frame.text)
+                if sh.shape_type == MSO_SHAPE_TYPE.PICTURE:
+                    has_pic = True
+            txt = re.sub(r"\s+", " ", " ".join(texts))
+            if "Distribuciones categ" not in txt:   # footer stamp of the chapter.
+                continue
+            for n in cat_names:
+                if n in txt:
+                    slides_with_col[n].append(i)
+                    has_table = "Cardinalidad" in txt or "distintos" in txt
+                    if has_pic and "donut" in txt and has_table:
+                        owner_has_chart[n] = True
+
+        for n in cat_names:
+            # Exactly one slide carries the column (not split across slides).
+            assert len(slides_with_col[n]) == 1, (n, slides_with_col[n])
+            # That single slide also holds its table AND its donut picture.
+            assert owner_has_chart[n], (n, "tabla y donut no están en el mismo slide")
+
+
 def test_edge_sin_categoricas_devuelve_none():
     only_numeric = {
         "n_rows": 10, "columns": [
@@ -170,11 +329,15 @@ def test_anti_corte_label_largo_y_muchas_columnas():
 
     ch = build_cat_distr(profile, {})
     assert ch is not None
+    # One Group per column, each forcing its own page (except the first).
+    groups = _column_groups(ch)
+    assert len(groups) == 30
+    assert sum(1 for g in groups if g.page_break_before) == 29
     with tempfile.TemporaryDirectory() as d:
         pdf = os.path.join(d, "anti.pdf")
         res = render_automatic_eda_pdf(profile, pdf, {"write_manifest": False})
         assert res["path"] == pdf
-        assert res["n_pages"] > 1       # many columns spilled across pages, OK.
+        assert res["n_pages"] > 1       # one page per column, OK.
         txt = _pdf_text(pdf)
         # Long label wrapped (not truncated): every word survives.
         for word in ("Lorem", "incididunt", "reprehenderit", "voluptate"):

python/functions/datascience/automatic_eda/chapters/missingness.py

@@ -0,0 +1,594 @@
+"""Missingness chapter (MISSINGNESS) — patterns of missing data.
+
+Complements the CALIDAD chapter: where CALIDAD reports *how much* is missing per
+column (the null percentage that lowers the completeness score), this chapter
+reports the **pattern** of the missing data — whether columns tend to be missing
+*together* (co-occurrence of absences) or independently. That distinction is what
+separates data that is missing completely at random ([[term:mcar]]MCAR[[/term]])
+from data missing as a function of another variable ([[term:mar]]MAR[[/term]]),
+which is the key question to settle before imputing or modelling.
+
+The chapter activates only when the table actually has missing data (at least one
+column with a null in the aggregated profile); otherwise it returns ``None`` and
+disappears from the document.
+
+Sections, in order:
+
+1. **Resumen global** — % of missing cells in the dataset, number of columns with
+   nulls, and complete rows (no missing) vs incomplete rows (≥1 missing).
+2. **Ranking por columna** — columns sorted by their null percentage, with a
+   horizontal bar figure.
+3. **Co-ocurrencia de ausencias** — the correlation of the binary is-null masks
+   between columns (which columns tend to be missing together): a heatmap plus a
+   table of the top column pairs that co-miss.
+4. **Patrones de fila** — the most frequent "which columns are missing together"
+   row patterns, in the style of missingno's pattern matrix.
+5. **Lectura MCAR/MAR** — an interpretive, *exploratory* note (not a confirmatory
+   test such as Little's) reading the absence correlations as a hint of MCAR
+   (independent absences) vs MAR (co-occurring absences).
+
+The aggregate per-column null counts come from the ``eda`` group ``TableProfile``
+(``columns[i]['null_count'] / 'null_pct'`` and the table-level ``null_cell_pct``).
+The per-row is-null mask needed for co-occurrence is built from raw data: a single
+DuckDB push-down over ``ctx['db_path'] / ctx['table']`` (same pattern as the
+AGREGACION chapter) covering ALL columns, with a fallback to the numeric-only
+``ctx['raw_numeric']`` when no database is reachable. All the heavy lifting is
+delegated to pure registry functions (``missingness_overview``,
+``missingness_correlation``, ``missingness_row_patterns``) and two figure helpers
+(``missingness_rank_bar_figure``, ``missingness_corr_heatmap_figure``); every one
+is imported lazily and degrades to an honest note so this chapter never raises.
+
+Contract: build_<id>(profile, ctx) -> Chapter | None ; CHAPTER_VERSION = "x.y.z".
+"""
+
+from __future__ import annotations
+
+from .. import model
+
+CHAPTER_VERSION = "1.0.0"
+CHAPTER_ID = "missingness"
+CHAPTER_TITLE = "Datos faltantes"
+
+# Sample cap for the per-row is-null mask push-down. Co-occurrence and row
+# patterns are computed on this sample; the global % of missing cells and the
+# per-column ranking come from the (exact) aggregated profile instead.
+MASK_SAMPLE = 5000
+# Thresholds for the MCAR/MAR heuristic note. A pair counts as a *strong*
+# co-occurrence when the absence correlation alone is high; as a *partial*
+# co-occurrence when the absences overlap materially (high Jaccard) even if the
+# Pearson correlation is modest — the usual case when one column is missing far
+# more often than the other (e.g. Cabin 77% vs Age 20% in Titanic), which dilutes
+# the correlation while the rows still co-miss in absolute terms.
+_CORR_STRONG = 0.30
+_JACCARD_NOTABLE = 0.20
+# Rows shown in the top-pairs and row-patterns tables (bounded, never silently
+# truncated: the table note reports the full count).
+_TOP_PAIRS = 12
+_TOP_PATTERNS = 12
+# Truncate long column names in tables (the renderer also wraps).
+_LABEL_MAX = 28
+
+# Glossary terms this chapter explains (contract §11.1). Registered in the shared
+# collector and marked clickable on their first appearance.
+_TERMS = {
+    "missingness": (
+        "Patrón de datos faltantes (missingness)",
+        "El patrón con el que faltan los datos: cuánto falta, en qué columnas y "
+        "si las ausencias de unas columnas coinciden (co-ocurren) con las de "
+        "otras. Analizarlo —no solo contar nulos— distingue datos que faltan al "
+        "azar (MCAR) de los que faltan en función de otra variable (MAR), lo que "
+        "decide cómo imputar o si descartar filas sin sesgar el análisis.",
+    ),
+    "mcar": (
+        "MCAR (Missing Completely At Random)",
+        "Los valores faltan de forma independiente de cualquier dato, observado o "
+        "no: las ausencias de unas columnas no se relacionan entre sí ni con los "
+        "valores. Es el caso más benigno —descartar filas o imputar la media no "
+        "introduce sesgo—, pero rara vez se cumple del todo en datos reales.",
+    ),
+    "mar": (
+        "MAR (Missing At Random)",
+        "La probabilidad de que un valor falte depende de OTRAS variables "
+        "observadas (p. ej. una medición que falta más en cierto grupo). Las "
+        "ausencias co-ocurren entre columnas o se relacionan con los valores de "
+        "otras; imputar exige condicionar en esas variables para no sesgar. La "
+        "co-ocurrencia fuerte de ausencias es un indicio (exploratorio) de MAR.",
+    ),
+}
+
+
+# --------------------------------------------------------------------------- #
+# Small defensive formatters (own copy: the chapter never imports siblings).
+# --------------------------------------------------------------------------- #
+def _fmt_int(value) -> str:
+    if value is None:
+        return "—"
+    try:
+        return f"{int(round(float(value))):,}".replace(",", ".")
+    except (TypeError, ValueError):
+        return model._safe_str(value)
+
+
+def _fmt_pct(value, decimals: int = 1) -> str:
+    """Format an already-0-100 value as a percentage. None -> placeholder."""
+    if value is None:
+        return "—"
+    try:
+        return f"{float(value):.{decimals}f}%"
+    except (TypeError, ValueError):
+        return model._safe_str(value)
+
+
+def _fmt_num(value, decimals: int = 3) -> str:
+    if value is None:
+        return "—"
+    try:
+        f = float(value)
+    except (TypeError, ValueError):
+        return model._safe_str(value)
+    if f != f:  # NaN
+        return "—"
+    text = f"{f:.{decimals}f}".rstrip("0").rstrip(".")
+    return text if text else "0"
+
+
+def _truncate(text, limit: int = _LABEL_MAX) -> str:
+    s = model._safe_str(text)
+    if len(s) <= limit:
+        return s
+    return s[: max(1, limit - 1)].rstrip() + "…"
+
+
+def _term(key: str, label: str, mark: bool) -> str:
+    if mark:
+        return f"[[term:{key}]]**{label}**[[/term]]"
+    return f"**{label}**"
+
+
+# --------------------------------------------------------------------------- #
+# Profile reads (exact, all rows).
+# --------------------------------------------------------------------------- #
+def _null_count_of(col: dict):
+    """Best-effort null count of a column: ``null_count`` or null_pct*n_rows."""
+    nc = col.get("null_count")
+    if isinstance(nc, (int, float)) and not isinstance(nc, bool):
+        return int(nc)
+    np_ = col.get("null_pct")
+    nr = col.get("n_rows")
+    if isinstance(np_, (int, float)) and isinstance(nr, (int, float)):
+        return int(round(float(np_) * float(nr)))
+    return 0
+
+
+def _columns_with_nulls(profile: dict):
+    """Return ``[(name, null_count, null_pct_0_100)]`` for columns with nulls,
+    sorted by null percentage descending. Reads the aggregated profile (exact)."""
+    cols = profile.get("columns") or []
+    out = []
+    for c in cols:
+        if not isinstance(c, dict):
+            continue
+        nc = _null_count_of(c)
+        if nc <= 0:
+            continue
+        np_ = c.get("null_pct")
+        nr = c.get("n_rows") or profile.get("n_rows")
+        if isinstance(np_, (int, float)) and not isinstance(np_, bool):
+            pct = float(np_) * 100.0 if np_ <= 1.0 else float(np_)
+        elif nr:
+            pct = nc / float(nr) * 100.0
+        else:
+            pct = None
+        out.append((c.get("name") or "(col)", nc, pct))
+    out.sort(key=lambda t: (t[2] if t[2] is not None else -1.0), reverse=True)
+    return out
+
+
+def _global_missing_pct(profile: dict):
+    """Table-level % of missing cells (0-100), exact, from the profile."""
+    v = profile.get("null_cell_pct")
+    if isinstance(v, (int, float)) and not isinstance(v, bool):
+        return float(v) * 100.0 if v <= 1.0 else float(v)
+    return None
+
+
+# --------------------------------------------------------------------------- #
+# Per-row is-null mask (sample): DuckDB push-down, fallback to raw_numeric.
+# --------------------------------------------------------------------------- #
+def _build_query_fn(ctx: dict):
+    """Return ``(query_fn, table)`` for a DuckDB-backed ctx, or ``(None, None)``.
+
+    Mirrors build_eda_render_ctx: a read-only closure over the registry wrapper.
+    Only DuckDB is supported here; any other backend degrades to raw_numeric."""
+    db_path = ctx.get("db_path")
+    table = ctx.get("table")
+    if not db_path or not table:
+        return None, None
+    try:
+        from infra import duckdb_query_readonly
+    except Exception:  # noqa: BLE001 — wrapper unavailable -> degrade.
+        return None, None
+
+    def query_fn(sql):
+        return duckdb_query_readonly(db_path, sql)
+
+    return query_fn, table
+
+
+def _null_mask(profile: dict, ctx: dict):
+    """Build the per-row is-null mask ``{col: [0/1, ...]}``.
+
+    Tries a single DuckDB push-down over ALL columns first (so categorical
+    columns like Cabin are covered, not only numeric ones); falls back to the
+    numeric-only ``ctx['raw_numeric']`` (None -> missing); returns ``(None, 0,
+    None)`` when neither is reachable. Never raises.
+    Returns ``(mask, n_sampled, source)`` with source in {"db","raw_numeric"}.
+    """
+    cols = profile.get("columns") or []
+    names = [c.get("name") for c in cols
+             if isinstance(c, dict) and c.get("name")]
+    # 1) DuckDB push-down over every column (covers categoricals too).
+    query_fn, table = _build_query_fn(ctx)
+    if query_fn is not None and names:
+        try:
+            from datascience.extract_null_mask import extract_null_mask
+
+            res = extract_null_mask(query_fn, table, names, max_rows=MASK_SAMPLE)
+            if isinstance(res, dict) and res.get("status") == "ok":
+                mask = res.get("mask") or {}
+                if mask:
+                    return mask, int(res.get("n") or 0), "db"
+        except Exception:  # noqa: BLE001 — degrade to raw_numeric.
+            pass
+    # 2) Fallback: numeric-only mask derived from raw_numeric (None -> missing).
+    rn = ctx.get("raw_numeric")
+    if isinstance(rn, dict) and rn:
+        mask = {}
+        for col, vals in rn.items():
+            if isinstance(vals, (list, tuple)):
+                mask[col] = [1 if v is None else 0 for v in vals]
+        if mask:
+            n = max((len(v) for v in mask.values()), default=0)
+            return mask, n, "raw_numeric"
+    return None, 0, None
+
+
+# --------------------------------------------------------------------------- #
+# Lazy registry delegations (each degrades to None on any failure).
+# --------------------------------------------------------------------------- #
+def _overview(mask: dict):
+    try:
+        from datascience.missingness_overview import missingness_overview
+
+        out = missingness_overview(mask)
+        return out if isinstance(out, dict) else None
+    except Exception:  # noqa: BLE001
+        return None
+
+
+def _correlation(mask: dict, top_k: int):
+    try:
+        from datascience.missingness_correlation import missingness_correlation
+
+        out = missingness_correlation(mask, top_k=top_k)
+        return out if isinstance(out, dict) else None
+    except Exception:  # noqa: BLE001
+        return None
+
+
+def _row_patterns(mask: dict, top_n: int):
+    try:
+        from datascience.missingness_row_patterns import missingness_row_patterns
+
+        out = missingness_row_patterns(mask, top_n=top_n)
+        return out if isinstance(out, dict) else None
+    except Exception:  # noqa: BLE001
+        return None
+
+
+def _rank_bar_make(names, pcts, title):
+    def make():
+        try:
+            from datascience.missingness_rank_bar_figure import (
+                missingness_rank_bar_figure,
+            )
+
+            return missingness_rank_bar_figure(names, pcts, title=title)
+        except Exception:  # noqa: BLE001 — minimal fallback figure.
+            return _fallback_fig("ranking de nulos no disponible")
+
+    return make
+
+
+def _heatmap_make(matrix, labels, title):
+    def make():
+        try:
+            from datascience.missingness_corr_heatmap_figure import (
+                missingness_corr_heatmap_figure,
+            )
+
+            return missingness_corr_heatmap_figure(matrix, labels, title=title)
+        except Exception:  # noqa: BLE001 — minimal fallback figure.
+            return _fallback_fig("heatmap de co-ocurrencia no disponible")
+
+    return make
+
+
+def _fallback_fig(message: str):
+    import matplotlib
+
+    matplotlib.use("Agg")
+    from matplotlib.figure import Figure
+
+    fig = Figure(figsize=(5.0, 2.2))
+    ax = fig.add_subplot(111)
+    ax.text(0.5, 0.5, message, ha="center", va="center")
+    ax.axis("off")
+    return fig
+
+
+# --------------------------------------------------------------------------- #
+# Block builders.
+# --------------------------------------------------------------------------- #
+def _summary_block(profile: dict, with_nulls: list, overview, sampled, n_total):
+    rows = []
+    gpct = _global_missing_pct(profile)
+    rows.append(("Celdas faltantes (global)", _fmt_pct(gpct)))
+    rows.append(("Columnas con faltantes", str(len(with_nulls))))
+    all_null = profile.get("all_null_cols")
+    if isinstance(all_null, (list, tuple)) and all_null:
+        rows.append(("Columnas 100% faltantes", str(len(all_null))))
+    if isinstance(overview, dict):
+        cr = overview.get("complete_rows")
+        ir = overview.get("incomplete_rows")
+        suffix = ""
+        if (isinstance(sampled, int) and isinstance(n_total, (int, float))
+                and sampled and n_total and sampled < n_total):
+            suffix = f" (sobre muestra de {_fmt_int(sampled)} filas)"
+        if cr is not None:
+            rows.append(("Filas completas (sin faltantes)",
+                         f"{_fmt_int(cr)} ({_fmt_pct(overview.get('complete_pct'))})"
+                         + suffix))
+        if ir is not None:
+            rows.append(("Filas con ≥1 faltante",
+                         f"{_fmt_int(ir)} "
+                         f"({_fmt_pct(overview.get('incomplete_pct'))})" + suffix))
+    return model.KVTable(rows=rows, title="Resumen de datos faltantes")
+
+
+def _ranking_block(with_nulls: list):
+    header = ["Columna", "Faltantes", "% faltante"]
+    rows = [[_truncate(n), _fmt_int(c), _fmt_pct(p)] for (n, c, p) in with_nulls]
+    if not rows:
+        return None
+    return model.DataTable(
+        header=header, rows=rows, title="Faltantes por columna",
+        note="ordenado de más a menos faltante")
+
+
+def _ranking_figure(with_nulls: list):
+    names = [n for (n, _, p) in with_nulls if p is not None]
+    pcts = [p for (_, _, p) in with_nulls if p is not None]
+    if not names:
+        return None
+    return model.Figure(
+        make=_rank_bar_make(names, pcts, "% de valores faltantes por columna"),
+        caption="Porcentaje de valores faltantes por columna (barras).")
+
+
+def _pairs_block(corr: dict):
+    """Top column pairs whose absences co-occur, as a table, or None."""
+    pairs = (corr or {}).get("pairs") or []
+    header = ["Columna A", "Columna B", "Corr. ausencia", "Co-faltan", "Jaccard"]
+    rows = []
+    for p in pairs[:_TOP_PAIRS]:
+        if not isinstance(p, dict):
+            continue
+        rows.append([
+            _truncate(p.get("a")),
+            _truncate(p.get("b")),
+            _fmt_num(p.get("corr")),
+            _fmt_int(p.get("co_missing")),
+            _fmt_num(p.get("jaccard")),
+        ])
+    if not rows:
+        return None
+    shown = len(rows)
+    total = len(pairs)
+    note = ("correlación de las máscaras is-null entre columnas; "
+            "«Co-faltan» = nº de filas en que ambas faltan a la vez")
+    if total > shown:
+        note += f" — top {shown} de {total} pares"
+    return model.DataTable(header=header, rows=rows,
+                           title="Pares de columnas que co-faltan", note=note)
+
+
+def _heatmap_block(corr: dict):
+    cols = (corr or {}).get("columns") or []
+    matrix = (corr or {}).get("matrix") or []
+    if len(cols) < 2 or not matrix:
+        return None
+    labels = [_truncate(c, 16) for c in cols]
+    return model.Figure(
+        make=_heatmap_make(matrix, labels, "Co-ocurrencia de ausencias"),
+        caption=("Correlación de las ausencias entre columnas (azul = faltan "
+                 "juntas; rojo = cuando una falta la otra tiende a estar)."))
+
+
+def _patterns_block(patterns_res: dict):
+    patterns = (patterns_res or {}).get("patterns") or []
+    header = ["Columnas que faltan juntas", "Filas", "%"]
+    rows = []
+    for p in patterns[:_TOP_PATTERNS]:
+        if not isinstance(p, dict):
+            continue
+        cols = p.get("missing_cols") or []
+        if cols:
+            label = ", ".join(_truncate(c, 18) for c in cols)
+        else:
+            label = "(fila completa — sin faltantes)"
+        rows.append([label, _fmt_int(p.get("n_rows")), _fmt_pct(p.get("pct"))])
+    if not rows:
+        return None
+    total = (patterns_res or {}).get("n_patterns")
+    shown = len(rows)
+    note = "cada fila es un patrón de «qué columnas faltan juntas»"
+    if isinstance(total, int) and total > shown:
+        note += f" — top {shown} de {total} patrones distintos"
+    return model.DataTable(header=header, rows=rows,
+                           title="Patrones de fila más comunes", note=note)
+
+
+def _mcar_mar_note(corr: dict, mark: bool):
+    """Interpretive, exploratory MCAR/MAR note from the absence correlations.
+
+    Reads the absence correlations at two levels so the verdict never contradicts
+    the visible evidence: a *strong* correlation flags a clear non-random (MAR)
+    pattern; a *partial* overlap (many rows co-miss — high Jaccard — even if the
+    correlation is diluted by one column being missing far more often) flags a
+    localized possible-MAR and cites the concrete co-missing pair; only when
+    neither holds does it read the absences as compatible with MCAR."""
+
+    def _pairs_with(attr_ok):
+        out = []
+        for p in (corr or {}).get("pairs") or []:
+            if isinstance(p, dict) and attr_ok(p):
+                out.append(p)
+        return out
+
+    def _cf(v):
+        try:
+            return float(v)
+        except (TypeError, ValueError):
+            return 0.0
+
+    strong = _pairs_with(lambda p: abs(_cf(p.get("corr"))) >= _CORR_STRONG)
+    partial = _pairs_with(
+        lambda p: _cf(p.get("corr")) > 0 and _cf(p.get("jaccard")) >= _JACCARD_NOTABLE)
+    mcar = _term("mcar", "MCAR", mark)
+    mar = _term("mar", "MAR", mark)
+    head = (
+        "**Lectura exploratoria MCAR/MAR.** Esta es una heurística basada en la "
+        "correlación de las ausencias entre columnas, NO un test confirmatorio "
+        "(como el de Little); orienta, no demuestra. ")
+    if strong:
+        top = strong[0]
+        ev = (f"«{model._safe_str(top.get('a'))}» y "
+              f"«{model._safe_str(top.get('b'))}» "
+              f"(corr {_fmt_num(top.get('corr'))})")
+        body = (
+            f"Hay ausencias que co-ocurren con fuerza —{ev}—: las columnas no "
+            f"faltan de forma independiente, lo que es un indicio de un patrón no "
+            f"aleatorio ({mar}). Antes de imputar o descartar filas conviene "
+            f"comprobar si la ausencia depende de otra variable observada; en ese "
+            f"caso la imputación debería condicionar en ella para no sesgar.")
+    elif partial:
+        top = max(partial, key=lambda p: _cf(p.get("jaccard")))
+        ev = (f"«{model._safe_str(top.get('a'))}» y "
+              f"«{model._safe_str(top.get('b'))}» faltan a la vez en "
+              f"{_fmt_int(top.get('co_missing'))} filas "
+              f"(Jaccard {_fmt_num(top.get('jaccard'))})")
+        body = (
+            f"Hay co-ocurrencia parcial de ausencias —{ev}—: algunas columnas "
+            f"tienden a faltar juntas aunque la correlación global sea modesta "
+            f"(habitual cuando una columna falta mucho más que la otra). Es un "
+            f"indicio de un posible patrón localizado no aleatorio ({mar}); "
+            f"conviene revisar si esa ausencia depende de otra variable observada "
+            f"antes de imputar, en lugar de asumir que faltan al azar.")
+    else:
+        body = (
+            f"Las ausencias entre columnas no muestran correlación ni solape "
+            f"relevante: parecen independientes, lo que es compatible con que "
+            f"falten al azar ({mcar}). Aun así, la ausencia podría depender de "
+            f"variables no observadas (la heurística no lo descarta).")
+    return model.Markdown(text=head + body)
+
+
+def _intro_block(mark: bool, source):
+    missingness = _term("missingness", "missingness", mark)
+    text = (
+        f"Este capítulo analiza el {missingness} de la tabla: no solo cuánto "
+        "falta (eso lo cubre la calidad), sino DÓNDE falta y si las columnas "
+        "faltan juntas. La co-ocurrencia de ausencias se calcula sobre la matriz "
+        "binaria «is-null» por fila.")
+    if source == "raw_numeric":
+        text += (" Nota: no se pudo leer la tabla cruda completa, así que la "
+                 "co-ocurrencia se limita a las columnas numéricas disponibles.")
+    return model.Markdown(text=text)
+
+
+# --------------------------------------------------------------------------- #
+# Entry point.
+# --------------------------------------------------------------------------- #
+def build_missingness(profile: dict, ctx: dict):
+    """Build the missingness Chapter, or None if the table has no missing data."""
+    if not isinstance(profile, dict):
+        profile = {}
+    ctx = ctx or {}
+
+    with_nulls = _columns_with_nulls(profile)
+    if not with_nulls:
+        return None  # no missing data anywhere -> chapter does not apply.
+
+    # Register glossary terms (if a collector is present) and mark them clickable.
+    glossary = ctx.get("glossary")
+    mark = False
+    if isinstance(glossary, model.GlossaryCollector):
+        for key, (label, definition) in _TERMS.items():
+            glossary.add(key, label, definition)
+        mark = True
+
+    # Per-row is-null mask (sample) for co-occurrence and row patterns.
+    mask, sampled, source = _null_mask(profile, ctx)
+    overview = _overview(mask) if mask else None
+    n_total = profile.get("n_rows")
+
+    blocks = [
+        model.Heading(text="Cuánto y dónde faltan datos", level=2),
+        _intro_block(mark, source),
+        _summary_block(profile, with_nulls, overview, sampled, n_total),
+        model.Heading(text="Faltantes por columna", level=2),
+    ]
+    ranking = _ranking_block(with_nulls)
+    if ranking is not None:
+        blocks.append(ranking)
+    rank_fig = _ranking_figure(with_nulls)
+    if rank_fig is not None:
+        blocks.append(rank_fig)
+
+    # Co-occurrence + row patterns need the per-row mask. Without it, say so.
+    if not mask:
+        blocks.append(model.Note(
+            "No se pudo construir la matriz «is-null» por fila (sin acceso a los "
+            "datos crudos), así que no se analiza la co-ocurrencia de ausencias "
+            "ni los patrones de fila en este informe."))
+        return model.Chapter(id=CHAPTER_ID, title=CHAPTER_TITLE,
+                             version=CHAPTER_VERSION, blocks=blocks)
+
+    corr = _correlation(mask, _TOP_PAIRS) or {}
+    co_blocks = [model.Heading(text="Co-ocurrencia de ausencias", level=2)]
+    heatmap = _heatmap_block(corr)
+    if heatmap is not None:
+        co_blocks.append(heatmap)
+    pairs = _pairs_block(corr)
+    if pairs is not None:
+        co_blocks.append(pairs)
+    if heatmap is None and pairs is None:
+        co_blocks.append(model.Note(
+            "Ninguna pareja de columnas comparte ausencias con variación "
+            "suficiente para correlacionarlas (p. ej. una sola columna con "
+            "faltantes), así que no hay co-ocurrencia que mostrar."))
+    # Keep the co-occurrence heading next to its heatmap and table.
+    blocks.append(model.Group(blocks=co_blocks))
+
+    patterns_res = _row_patterns(mask, _TOP_PATTERNS) or {}
+    patterns = _patterns_block(patterns_res)
+    if patterns is not None:
+        blocks.append(model.Heading(text="Patrones de fila", level=2))
+        blocks.append(patterns)
+
+    blocks.append(model.Heading(text="Lectura MCAR / MAR", level=2))
+    blocks.append(_mcar_mar_note(corr, mark))
+
+    return model.Chapter(id=CHAPTER_ID, title=CHAPTER_TITLE,
+                         version=CHAPTER_VERSION, blocks=blocks)

python/functions/datascience/automatic_eda/chapters/missingness_test.py

@@ -0,0 +1,162 @@
+"""Tests for the MISSINGNESS chapter.
+
+Covers the Definition of Done for this chapter:
+  * Activates (non-None Chapter with the expected sections) when the profile has
+    missing data, building the co-occurrence from the per-row is-null mask.
+  * Returns None when the table has no missing data at all (edge case).
+  * Registers the MCAR/MAR/missingness glossary terms.
+  * The DuckDB push-down path covers categorical columns (not only numeric),
+    so a categorical column that co-misses with a numeric one is detected.
+"""
+
+import os
+import sys
+
+_HERE = os.path.dirname(os.path.abspath(__file__))
+_FUNCTIONS = os.path.abspath(os.path.join(_HERE, "..", "..", ".."))  # python/functions
+if _FUNCTIONS not in sys.path:
+    sys.path.insert(0, _FUNCTIONS)
+
+from datascience.automatic_eda import model  # noqa: E402
+from datascience.automatic_eda.chapters.missingness import (  # noqa: E402
+    build_missingness,
+)
+
+
+def _titles(chapter):
+    """Collect heading texts and table/figure titles for assertions."""
+    out = []
+    for b in chapter.blocks:
+        kind = getattr(b, "kind", None)
+        if kind == "heading":
+            out.append(("heading", getattr(b, "text", "")))
+        elif kind in ("data_table", "kv_table"):
+            out.append((kind, getattr(b, "title", "")))
+        elif kind == "group":
+            for inner in getattr(b, "blocks", []):
+                ik = getattr(inner, "kind", None)
+                if ik == "heading":
+                    out.append(("heading", getattr(inner, "text", "")))
+                elif ik in ("data_table", "kv_table"):
+                    out.append((ik, getattr(inner, "title", "")))
+                elif ik == "figure":
+                    out.append(("figure", getattr(inner, "caption", "")))
+        elif kind == "figure":
+            out.append(("figure", getattr(b, "caption", "")))
+    return out
+
+
+def _all_text(chapter):
+    parts = []
+    def walk(blocks):
+        for b in blocks:
+            for attr in ("text", "title", "note", "caption"):
+                v = getattr(b, attr, None)
+                if v:
+                    parts.append(str(v))
+            if getattr(b, "kind", None) == "group":
+                walk(getattr(b, "blocks", []))
+    walk(chapter.blocks)
+    return "\n".join(parts)
+
+
+def test_returns_none_when_no_missing_data():
+    profile = {
+        "n_rows": 4,
+        "null_cell_pct": 0.0,
+        "columns": [
+            {"name": "a", "null_count": 0, "null_pct": 0.0, "n_rows": 4},
+            {"name": "b", "null_count": 0, "null_pct": 0.0, "n_rows": 4},
+        ],
+    }
+    assert build_missingness(profile, {}) is None
+
+
+def test_activates_with_cooccurrence_via_raw_numeric():
+    # a and b are missing in EXACTLY the same rows (0,1,2) -> perfect absence
+    # correlation. c has no nulls. No db_path -> the chapter falls back to the
+    # numeric raw_numeric mask.
+    profile = {
+        "n_rows": 6,
+        "null_cell_pct": (0.5 + 0.5 + 0.0) / 3.0,
+        "columns": [
+            {"name": "a", "null_count": 3, "null_pct": 0.5, "n_rows": 6},
+            {"name": "b", "null_count": 3, "null_pct": 0.5, "n_rows": 6},
+            {"name": "c", "null_count": 0, "null_pct": 0.0, "n_rows": 6},
+        ],
+    }
+    glossary = model.GlossaryCollector()
+    ctx = {
+        "raw_numeric": {
+            "a": [None, None, None, 1.0, 2.0, 3.0],
+            "b": [None, None, None, 4.0, 5.0, 6.0],
+        },
+        "glossary": glossary,
+    }
+    ch = build_missingness(profile, ctx)
+    assert ch is not None
+    assert ch.id == "missingness"
+    assert ch.blocks
+
+    titles = _titles(ch)
+    headings = {t for (k, t) in titles if k == "heading"}
+    # Core sections present.
+    assert any("Cuánto y dónde" in h for h in headings)
+    assert any("Faltantes por columna" in h for h in headings)
+    assert any("Co-ocurrencia" in h for h in headings)
+    assert any("MCAR" in h for h in headings)
+    # A summary KVTable, a ranking DataTable, a co-occurrence figure and the
+    # pairs table all exist.
+    kinds = {k for (k, _) in titles}
+    assert "kv_table" in kinds
+    assert "data_table" in kinds
+    assert "figure" in kinds
+
+    # Glossary terms registered.
+    keys = {t["key"] for t in glossary.terms()}
+    assert {"missingness", "mcar", "mar"} <= keys
+
+    # The MCAR/MAR note reads the co-occurrence; with a perfect overlap it must
+    # flag the non-random (MAR) reading.
+    text = _all_text(ch)
+    assert "MAR" in text
+
+
+def test_db_pushdown_covers_categorical_column(tmp_path):
+    """The is-null mask push-down must cover a categorical column, so a
+    categorical that co-misses with a numeric one shows up in the pairs."""
+    import duckdb
+
+    db = str(tmp_path / "miss.duckdb")
+    con = duckdb.connect(db)
+    con.execute("CREATE TABLE t (num1 DOUBLE, num2 DOUBLE, cat VARCHAR)")
+    # num1 and cat are NULL together in the first 4 of 10 rows; num2 never null.
+    rows = []
+    for i in range(10):
+        if i < 4:
+            rows.append((None, float(i), None))
+        else:
+            rows.append((float(i), float(i), f"c{i}"))
+    con.executemany("INSERT INTO t VALUES (?,?,?)", rows)
+    con.close()
+
+    profile = {
+        "n_rows": 10,
+        "null_cell_pct": (0.4 + 0.0 + 0.4) / 3.0,
+        "columns": [
+            {"name": "num1", "null_count": 4, "null_pct": 0.4, "n_rows": 10},
+            {"name": "num2", "null_count": 0, "null_pct": 0.0, "n_rows": 10},
+            {"name": "cat", "null_count": 4, "null_pct": 0.4, "n_rows": 10},
+        ],
+    }
+    ctx = {"db_path": db, "table": "t", "glossary": model.GlossaryCollector()}
+    ch = build_missingness(profile, ctx)
+    assert ch is not None
+
+    # The pairs table must mention both num1 and cat (they co-miss perfectly),
+    # which is only possible if the mask covered the categorical column.
+    text = _all_text(ch)
+    assert "num1" in text and "cat" in text
+    # Co-occurrence section + a pairs data table exist.
+    titles = _titles(ch)
+    assert any("co-faltan" in (t or "").lower() for (k, t) in titles)

python/functions/datascience/automatic_eda/chapters_registry.py

@@ -32,6 +32,7 @@ CHAPTER_ORDER = [
     "num_distr",     # numeric distributions
     "cat_distr",     # categorical distributions
     "calidad",       # data quality
+    "missingness",   # missing-data patterns (co-occurrence of absences; MCAR/MAR)
     "correlacion",   # correlations / associations
     "relaciones",    # key relations: declared/candidate PK + FK (inter/intra-table)
     "modelos",       # cheap models (PCA/KMeans/outliers)

python/functions/datascience/automatic_eda/model.py

@@ -139,10 +139,17 @@ class Group:
     it starts on a fresh page and flows (honest degradation, never cut). Use it to
     bind ``Heading`` + ``Markdown`` + ``Figure`` of one idea together (see the
     DISTR NUM / AGREGACION chapters).
+
+    When ``page_break_before`` is True the renderer additionally forces the group
+    to *start* on a fresh page/slide (unless the current one is already empty), so
+    a chapter can give each unit its own page — e.g. one categorical column per
+    page (see CAT DISTR). It is purely additive: the default False keeps the plain
+    keep-together behaviour for every existing chapter.
     """
 
     blocks: list = field(default_factory=list)
     title: Optional[str] = None
+    page_break_before: bool = False
     kind: str = field(default="group", init=False)
 
 
@@ -228,7 +235,9 @@ def as_block(obj: Any):
                 return Note(text=_safe_str(obj.get("text")))
             if cls is Group:
                 return Group(blocks=as_blocks(obj.get("blocks")),
-                             title=obj.get("title"))
+                             title=obj.get("title"),
+                             page_break_before=bool(
+                                 obj.get("page_break_before", False)))
             if cls is GlossaryEntry:
                 return GlossaryEntry(key=_safe_str(obj.get("key")),
                                      label=_safe_str(obj.get("label")),

python/functions/datascience/automatic_eda/render_md_impl.py

@@ -0,0 +1,458 @@
+"""AutomaticEDA Markdown serializer — one self-contained file to paste to an LLM.
+
+Same document model as the PDF/PPTX renderers (an ordered list of
+:class:`Chapter`, each a list of format-independent blocks) but emitted as plain
+**Markdown** instead of a binary. The goal is different from the other two
+renderers: a Markdown EDA is meant to be *pasted into an LLM*, so it prioritises
+TEXT and DATA over visuals. Tables become Markdown tables (every row dumped, no
+pagination — nothing is cut because there are no pages); a ``Figure`` becomes its
+caption plus, when possible, the underlying bar/histogram data as a Markdown
+table (an LLM cannot see the image); glossary term markers are stripped while
+``**bold**`` is kept (it is valid Markdown).
+
+dict-no-throw (the ``eda`` group style): :func:`render_md` never raises. On a
+fatal error it returns ``{path: None, ...}`` with a ``note`` explaining why; a
+malformed block degrades to a readable note rather than crashing the document.
+"""
+
+from __future__ import annotations
+
+import os
+import re
+
+from . import model
+
+# Glossary span markers (kept text, dropped markers). We intentionally do NOT use
+# ``text_layout.strip_inline_md`` for Markdown blocks because that also removes
+# ``**bold**`` — valid Markdown we want to preserve when pasting to an LLM.
+_TERM_OPEN_RE = re.compile(r"\[\[term:[A-Za-z0-9_]+\]\]")
+_MAX_BAR_ROWS = 100
+
+
+# --------------------------------------------------------------------------- #
+# Small helpers.
+# --------------------------------------------------------------------------- #
+def _clean_terms(s) -> str:
+    """Drop glossary term markers, keeping the visible text (and any **bold**)."""
+    s = model._safe_str(s)
+    s = _TERM_OPEN_RE.sub("", s)
+    return s.replace("[[/term]]", "")
+
+
+def _cell(v) -> str:
+    """Render a value as a safe Markdown table cell.
+
+    Escapes pipes (``|`` -> ``\\|``) so they do not break the column layout and
+    folds newlines to ``<br>`` so a multi-line value stays inside one cell. None
+    becomes an empty string.
+    """
+    s = model._safe_str(v)
+    s = s.replace("|", "\\|")
+    s = s.replace("\r\n", "\n").replace("\r", "\n").replace("\n", "<br>")
+    return s
+
+
+def _slug(text: str) -> str:
+    """GitHub-style heading anchor: lowercase, spaces->'-', drop other symbols."""
+    s = model._safe_str(text).strip().lower()
+    out = []
+    for ch in s:
+        if ch.isalnum():
+            out.append(ch)
+        elif ch in " -":
+            out.append("-")
+        # any other symbol is dropped.
+    slug = "".join(out)
+    while "--" in slug:
+        slug = slug.replace("--", "-")
+    return slug.strip("-")
+
+
+def _fmt_num(v) -> str:
+    """Compact number for the figure data tables (ints as ints, else 4 sig figs)."""
+    try:
+        f = float(v)
+    except Exception:  # noqa: BLE001
+        return model._safe_str(v)
+    if f != f:  # NaN
+        return "NaN"
+    if f == int(f) and abs(f) < 1e15:
+        return str(int(f))
+    return f"{f:.4g}"
+
+
+def _fmt_int(v) -> str:
+    try:
+        return str(int(v))
+    except Exception:  # noqa: BLE001
+        return model._safe_str(v)
+
+
+def _now_iso() -> str:
+    from datetime import datetime, timezone
+    return datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M:%S UTC")
+
+
+# --------------------------------------------------------------------------- #
+# Document header (title + metadata blockquote + numbered index).
+# --------------------------------------------------------------------------- #
+def _meta_block(meta: dict) -> list:
+    """Build the metadata lines for the header blockquote (omitting absentees)."""
+    ctx = meta.get("ctx") if isinstance(meta.get("ctx"), dict) else {}
+    lines: list = []
+
+    def add(label, value) -> None:
+        if value is None:
+            return
+        s = model._safe_str(value).strip()
+        if s and s.lower() != "none":
+            lines.append(f"**{label}:** {s}")
+
+    add("Dataset", ctx.get("dataset_name") or meta.get("dataset_name"))
+    add("Fuente", ctx.get("source_origin") or meta.get("source_origin"))
+    add("Almacenamiento", ctx.get("storage") or meta.get("storage"))
+    n_rows = ctx.get("n_rows", meta.get("n_rows"))
+    n_cols = ctx.get("n_cols", meta.get("n_cols"))
+    if n_rows is not None and n_cols is not None:
+        lines.append(
+            f"**Dimensiones:** {_fmt_int(n_rows)} filas × {_fmt_int(n_cols)} columnas")
+    add("Generado", meta.get("generated_at") or _now_iso())
+    lines.append(f"**Motor:** {model.ENGINE_NAME} v{model.ENGINE_VERSION}")
+    return lines
+
+
+# --------------------------------------------------------------------------- #
+# Per-block serializers. Each returns a Markdown string (no surrounding blanks;
+# the caller separates blocks with a blank line).
+# --------------------------------------------------------------------------- #
+def _md_heading(block) -> str:
+    level = int(getattr(block, "level", 1) or 1)
+    hashes = "#" * min(level + 2, 6)  # level1 -> ###; '#'/'##' reserved for doc/chapter.
+    text = _clean_terms(getattr(block, "text", "")).strip()
+    return f"{hashes} {text}"
+
+
+def _md_markdown(block) -> str:
+    # Keep the text verbatim, dropping only glossary markers (keep **bold**).
+    return _clean_terms(getattr(block, "text", "")).rstrip("\n")
+
+
+def _md_kv_table(block) -> str:
+    lines: list = []
+    title = getattr(block, "title", None)
+    if title:
+        lines.append(f"**{_clean_terms(title).strip()}**")
+        lines.append("")
+    lines.append("| Campo | Valor |")
+    lines.append("| --- | --- |")
+    for row in (getattr(block, "rows", []) or []):
+        try:
+            label, value = row[0], row[1]
+        except Exception:  # noqa: BLE001
+            label, value = row, ""
+        lines.append(f"| {_cell(label)} | {_cell(value)} |")
+    return "\n".join(lines)
+
+
+def _md_data_table(block) -> str:
+    lines: list = []
+    title = getattr(block, "title", None)
+    if title:
+        lines.append(f"**{_clean_terms(title).strip()}**")
+        lines.append("")
+    header = list(getattr(block, "header", []) or [])
+    rows = list(getattr(block, "rows", []) or [])
+    if not header:
+        ncol = max((len(r) for r in rows), default=1)
+        header = [f"col{i + 1}" for i in range(ncol)]
+    ncol = len(header)
+    lines.append("| " + " | ".join(_cell(h) for h in header) + " |")
+    lines.append("| " + " | ".join(["---"] * ncol) + " |")
+    for r in rows:  # dump every row — no pagination, nothing cut.
+        cells = [_cell(r[c]) if c < len(r) else "" for c in range(ncol)]
+        lines.append("| " + " | ".join(cells) + " |")
+    note = getattr(block, "note", None)
+    if note:
+        lines.append("")
+        lines.append(f"*{_clean_terms(note).strip()}*")
+    return "\n".join(lines)
+
+
+def _bars_table(bars: list) -> str:
+    """Render extracted bar/histogram data as a Markdown table (Desde/Hasta/Frec)."""
+    lines = ["| Desde | Hasta | Frecuencia |", "| --- | --- | --- |"]
+    shown = bars[:_MAX_BAR_ROWS]
+    for x0, x1, h in shown:
+        lines.append(f"| {_fmt_num(x0)} | {_fmt_num(x1)} | {_fmt_num(h)} |")
+    out = "\n".join(lines)
+    extra = len(bars) - len(shown)
+    if extra > 0:
+        out += f"\n\n*… ({extra} filas más)*"
+    return out
+
+
+def _extract_bars(fig) -> list:
+    """Collect (x_from, x_to, height) of the rectangular bars of a matplotlib fig.
+
+    Histogram / bar-chart bars are ``matplotlib.patches.Rectangle`` with positive
+    width and height; spines, legends and zero-area artists are skipped. Never
+    raises — returns ``[]`` on any problem.
+    """
+    bars: list = []
+    try:
+        for ax in fig.get_axes():
+            # Collect this axes' positive-area rectangles, then keep only the ones
+            # that look like actual histogram/bar bins. Reference shapes that
+            # matplotlib also stores in ``ax.patches`` — most notably the ``±1σ``
+            # band drawn by ``axvspan`` (a single rectangle far wider than a bin)
+            # and a lone Tukey boxplot box — would otherwise show up as fake
+            # "bins". A histogram axes has several near-equal-width bars, so we
+            # drop any rectangle whose width is more than twice the median width
+            # of that axes' rectangles (the σ-band spans many bins; uniform bins
+            # all sit at the median width and stay).
+            ax_bars: list = []
+            for patch in list(getattr(ax, "patches", []) or []):
+                try:
+                    w = patch.get_width()
+                    h = patch.get_height()
+                    x = patch.get_x()
+                except Exception:  # noqa: BLE001 — not a Rectangle-like patch.
+                    continue
+                if w and w > 0 and h and h > 0:
+                    ax_bars.append((x, x + w, h))
+            if len(ax_bars) >= 3:
+                widths = sorted(b[1] - b[0] for b in ax_bars)
+                median_w = widths[len(widths) // 2]
+                if median_w > 0:
+                    ax_bars = [b for b in ax_bars
+                               if (b[1] - b[0]) <= 2.0 * median_w]
+            bars.extend(ax_bars)
+    except Exception:  # noqa: BLE001
+        return []
+    return bars
+
+
+def _md_figure(block, meta: dict, out_path: str, counter: list) -> str:
+    """Serialize a Figure prioritising TEXT + DATA (an LLM cannot see the image).
+
+    Emits the caption, then — if the matplotlib figure has bars — a Markdown table
+    of the underlying (Desde, Hasta, Frecuencia) values. Optionally (when
+    ``meta['embed_figures']`` is True) also exports a PNG beside the .md and adds
+    an image link; off by default so the Markdown stays self-contained.
+    """
+    caption = model._safe_str(getattr(block, "caption", "")).strip()
+    parts = [f"*Figura: {caption}*" if caption else "*Figura*"]
+    fig = None
+    try:
+        import matplotlib
+        matplotlib.use("Agg")  # defensive: headless rasterization backend.
+        fig = getattr(block, "fig", None)
+        make = getattr(block, "make", None)
+        if fig is None and callable(make):
+            fig = make()
+        if fig is not None:
+            bars = _extract_bars(fig)
+            if bars:
+                parts.append(_bars_table(bars))
+            if meta.get("embed_figures"):
+                png = _embed_png(fig, out_path, counter)
+                if png:
+                    parts.append(f"![{caption}]({png})")
+    except Exception:  # noqa: BLE001 — a bad figure degrades to just its caption.
+        pass
+    finally:
+        if fig is not None:
+            try:
+                import matplotlib.pyplot as plt
+                plt.close(fig)
+            except Exception:  # noqa: BLE001
+                pass
+    return "\n\n".join(parts)
+
+
+def _embed_png(fig, out_path: str, counter: list) -> str:
+    """Export the figure to ``<basename>_figN.png`` beside the .md; return its name."""
+    try:
+        counter[0] += 1
+        base = os.path.splitext(os.path.basename(out_path))[0] or "figura"
+        name = f"{base}_fig{counter[0]}.png"
+        path = os.path.join(os.path.dirname(os.path.abspath(out_path)), name)
+        fig.savefig(path, format="png", dpi=120, bbox_inches="tight")
+        return name
+    except Exception:  # noqa: BLE001
+        return ""
+
+
+def _md_image(block) -> str:
+    path = model._safe_str(getattr(block, "path", ""))
+    caption = model._safe_str(getattr(block, "caption", "")).strip()
+    out = f"![{caption}]({path})"
+    if caption:
+        out += f"\n\n*{caption}*"
+    return out
+
+
+def _md_caption(block) -> str:
+    return f"*{_clean_terms(getattr(block, 'text', '')).strip()}*"
+
+
+def _md_note(block) -> str:
+    text = _clean_terms(getattr(block, "text", "")).strip()
+    lines = text.split("\n")
+    return "\n".join((f"> {ln}" if ln.strip() else ">") for ln in lines)
+
+
+def _md_group(block, meta: dict, out_path: str, counter: list) -> str:
+    parts: list = []
+    title = getattr(block, "title", None)
+    if title:
+        parts.append(f"### {_clean_terms(title).strip()}")
+    for b in (getattr(block, "blocks", []) or []):
+        try:
+            seg = _serialize_block(b, meta, out_path, counter)
+        except Exception:  # noqa: BLE001
+            seg = ""
+        if seg:
+            parts.append(seg)
+    return "\n\n".join(parts)
+
+
+def _md_glossary_entry(block) -> str:
+    label = (model._safe_str(getattr(block, "label", "")).strip()
+             or model._safe_str(getattr(block, "key", "")).strip())
+    definition = _clean_terms(getattr(block, "definition", "")).strip()
+    out = f"### {label}"
+    if definition:
+        out += f"\n\n{definition}"
+    return out
+
+
+def _serialize_block(block, meta: dict, out_path: str, counter: list) -> str:
+    """Dispatch a single block to its Markdown serializer. Unknown -> note."""
+    kind = getattr(block, "kind", "")
+    if kind == "heading":
+        return _md_heading(block)
+    if kind == "markdown":
+        return _md_markdown(block)
+    if kind == "kv_table":
+        return _md_kv_table(block)
+    if kind == "data_table":
+        return _md_data_table(block)
+    if kind == "figure":
+        return _md_figure(block, meta, out_path, counter)
+    if kind == "image":
+        return _md_image(block)
+    if kind == "caption":
+        return _md_caption(block)
+    if kind == "note":
+        return _md_note(block)
+    if kind == "group":
+        return _md_group(block, meta, out_path, counter)
+    if kind == "glossary_entry":
+        return _md_glossary_entry(block)
+    # Unknown content -> readable note (mirrors the model's defensive coercion).
+    return _md_note(model.Note(text=model._safe_str(block)))
+
+
+# --------------------------------------------------------------------------- #
+# Entry point.
+# --------------------------------------------------------------------------- #
+def render_md(chapters: list, out_path: str, meta: dict = None) -> dict:
+    """Serialize a list of Chapters into a single self-contained Markdown file.
+
+    The output leads with ``# <title>``, a metadata blockquote and a numbered
+    ``## Índice`` linking each chapter, then one ``## N. <title>`` section per
+    chapter with its blocks. Tables become Markdown tables (every row dumped),
+    figures become caption + underlying data table, glossary markers are stripped
+    while ``**bold**`` is kept. Designed to be pasted into an LLM.
+
+    Args:
+        chapters: a list of ``Chapter`` (dataclasses or dicts); normalized
+            defensively with ``model.as_chapters``.
+        out_path: filesystem path for the ``.md`` (parent dirs are created).
+        meta: optional dict. Recognised keys: ``title``, ``ctx`` (dict with
+            ``dataset_name``/``source_origin``/``storage``/``n_rows``/``n_cols``),
+            ``generated_at``, ``embed_figures`` (export PNGs beside the .md,
+            default False).
+
+    Returns:
+        dict (never raises): ``{path: str|None, n_chars: int,
+        chapters: list[{id, version}], note: str}``. On a fatal error ``path`` is
+        None and ``note`` explains why.
+    """
+    meta = meta or {}
+    chapters = model.as_chapters(chapters)
+    title = model._safe_str(meta.get("title")) or model.ENGINE_NAME
+
+    # Edge: nothing to render -> a minimal but valid Markdown document.
+    if not chapters:
+        content = (f"# {title}\n\n"
+                   "*(documento vacío — sin capítulos aplicables)*\n")
+        return _write(out_path, content, [], "documento vacío")
+
+    counter = [0]  # document-wide figure counter for unique PNG names.
+    notes: list = []
+    segments: list = [f"# {title}"]
+
+    meta_lines = _meta_block(meta)
+    if meta_lines:
+        segments.append("\n".join(f"> {ln}" for ln in meta_lines))
+
+    # Numbered index. The anchor matches the chapter heading emitted below
+    # (``## N. <title>``) in GitHub slug style.
+    chap_heads = []
+    idx_lines = ["## Índice"]
+    for i, ch in enumerate(chapters, 1):
+        head_text = f"{i}. {model._safe_str(ch.title)}"
+        anchor = _slug(head_text)
+        chap_heads.append((head_text, anchor))
+        idx_lines.append(f"{i}. [{model._safe_str(ch.title)}](#{anchor})")
+    segments.append("\n".join(idx_lines))
+
+    chapters_meta = []
+    for i, ch in enumerate(chapters, 1):
+        segments.append("---")
+        head_text, _anchor = chap_heads[i - 1]
+        segments.append(f"## {head_text}")
+
+        blocks = list(ch.blocks or [])
+        # Omit a leading level-1 Heading that just repeats the chapter title.
+        if blocks:
+            b0 = blocks[0]
+            if (getattr(b0, "kind", "") == "heading"
+                    and int(getattr(b0, "level", 1) or 1) == 1
+                    and _clean_terms(getattr(b0, "text", "")).strip()
+                    == model._safe_str(ch.title).strip()):
+                blocks = blocks[1:]
+
+        for block in blocks:
+            try:
+                seg = _serialize_block(block, meta, out_path, counter)
+            except Exception as e:  # noqa: BLE001
+                seg = _md_note(model.Note(text=model._safe_str(block)))
+                notes.append(
+                    f"bloque '{getattr(block, 'kind', '?')}' del capítulo "
+                    f"'{ch.id}' degradado: {e}")
+            if seg:
+                segments.append(seg)
+        chapters_meta.append({"id": ch.id, "version": ch.version})
+
+    content = "\n\n".join(segments) + "\n"
+    note = f"{len(content)} caracteres"
+    if notes:
+        note += " · " + "; ".join(notes)
+    return _write(out_path, content, chapters_meta, note)
+
+
+def _write(out_path: str, content: str, chapters_meta: list, note: str) -> dict:
+    """Write the Markdown to disk (creating parents). dict-no-throw."""
+    try:
+        parent = os.path.dirname(os.path.abspath(out_path))
+        os.makedirs(parent, exist_ok=True)
+        with open(out_path, "w", encoding="utf-8") as fh:
+            fh.write(content)
+    except Exception as e:  # noqa: BLE001 — never raise from the writer.
+        return {"path": None, "n_chars": 0, "chapters": [],
+                "note": f"no se pudo escribir el Markdown: {e}"}
+    return {"path": out_path, "n_chars": len(content),
+            "chapters": chapters_meta, "note": note}

python/functions/datascience/automatic_eda/render_pdf_impl.py

@@ -675,6 +675,61 @@ def _measure_figure_like(block) -> float:
     return target_h + 0.04 + cap_h + _GAP
 
 
+def _measure_kv_table(block) -> float:
+    """Faithful height of a KVTable — matches ``_place_kv_table``.
+
+    Counts the optional title heading and, per row, the wrapped VALUE column
+    (the label column never wraps in the placer). The previous estimate assumed
+    one line per row and ignored the title, so a column's keep-together Group
+    under-budgeted the figure and the chart spilled to the next page. Keep this in
+    sync with ``_place_kv_table``."""
+    h = 0.0
+    title = getattr(block, "title", None)
+    if title:
+        h += _measure_heading_text(title, 2)
+    rows = getattr(block, "rows", []) or []
+    key_w = 1.9
+    val_chars = tl.chars_per_line(_USABLE_W - key_w - 0.1, _FS_BODY)
+    lh = tl.line_height_in(_FS_BODY)
+    for row in rows:
+        try:
+            value = row[1]
+        except Exception:  # noqa: BLE001
+            value = ""
+        v_lines = tl.wrap(model._safe_str(value), val_chars)
+        h += lh * len(v_lines) + _ROW_VPAD
+    return h + _GAP
+
+
+def _measure_data_table(block) -> float:
+    """Faithful height of a DataTable — matches ``_place_data_table``.
+
+    Counts the optional title heading, the wrapped header row, every wrapped data
+    row (per-column wrap via the same ``_col_widths``/``_wrap_row`` the placer
+    uses) and the optional note. Keep this in sync with ``_place_data_table``."""
+    h = 0.0
+    title = getattr(block, "title", None)
+    if title:
+        h += _measure_heading_text(title, 2)
+    header = list(getattr(block, "header", []) or [])
+    rows = list(getattr(block, "rows", []) or [])
+    fs = _FS_CELL
+    widths = _col_widths(header, rows, fs)
+    lh = tl.line_height_in(fs)
+    if header:
+        header_lines = _wrap_row(header, widths, fs)
+        h += lh * max((len(c) for c in header_lines), default=1) + _ROW_VPAD * 2
+    for r in rows:
+        cells_lines = _wrap_row(r, widths, fs)
+        h += lh * max((len(c) for c in cells_lines), default=1) + _ROW_VPAD * 2
+    note = getattr(block, "note", None)
+    if note:
+        nlines = tl.wrap(model._safe_str(note),
+                         tl.chars_per_line(_USABLE_W, _FS_NOTE))
+        h += tl.line_height_in(_FS_NOTE) * len(nlines)
+    return h + _GAP
+
+
 def _measure_block(st: _PdfState, block) -> float:
     kind = getattr(block, "kind", "")
     try:
@@ -690,13 +745,9 @@ def _measure_block(st: _PdfState, block) -> float:
                             tl.chars_per_line(_USABLE_W, _FS_NOTE))
             return tl.line_height_in(_FS_NOTE) * len(lines) + _GAP
         if kind == "kv_table":
-            rows = getattr(block, "rows", []) or []
-            return (tl.line_height_in(_FS_BODY) + _ROW_VPAD) * (len(rows) + 1) \
-                + _GAP
+            return _measure_kv_table(block)
         if kind == "data_table":
-            rows = getattr(block, "rows", []) or []
-            return (tl.line_height_in(_FS_CELL) + _ROW_VPAD * 2) \
-                * (len(rows) + 1) + _GAP
+            return _measure_data_table(block)
         if kind == "group":
             return sum(_measure_block(st, b)
                        for b in (getattr(block, "blocks", []) or []))
@@ -735,6 +786,10 @@ def _place_group(st: _PdfState, block) -> None:
     blocks = getattr(block, "blocks", []) or []
     if not blocks:
         return
+    # Opt-in page break: start this group on a fresh page unless the current one
+    # is still empty (so a chapter can give each unit its own page).
+    if getattr(block, "page_break_before", False) and st.y > _CONTENT_TOP + 1e-6:
+        _new_page(st)
     avail_full = _CONTENT_BOTTOM - _CONTENT_TOP
     _shrink_group_figures(st, blocks, avail_full)
     total = sum(_measure_block(st, b) for b in blocks)

python/functions/datascience/automatic_eda/render_pptx_impl.py

@@ -625,6 +625,55 @@ def _measure_figure_like(block) -> float:
     return target_h + 0.05 + cap_h + _GAP
 
 
+def _measure_kv_table(block) -> float:
+    """Faithful KVTable height — matches ``_place_kv_table`` (rendered as a
+    Campo/Valor data table with wrapped cells). The previous estimate assumed one
+    line per row and ignored the title, so a keep-together Group under-budgeted
+    the figure and the chart spilled to the next slide. Keep in sync."""
+    h = 0.0
+    title = getattr(block, "title", None)
+    if title:
+        h += _measure_heading_text(title, 2)
+    rows = getattr(block, "rows", []) or []
+    data_rows = []
+    for row in rows:
+        try:
+            label, value = row[0], row[1]
+        except Exception:  # noqa: BLE001
+            label, value = str(row), ""
+        data_rows.append([model._safe_str(label), model._safe_str(value)])
+    header = ["Campo", "Valor"]
+    widths = _col_widths(header, data_rows)
+    fs = _FS_CELL
+    h += _row_height_in(header, widths, fs)
+    for r in data_rows:
+        h += _row_height_in(r, widths, fs)
+    return h + _GAP
+
+
+def _measure_data_table(block) -> float:
+    """Faithful DataTable height — matches ``_place_data_table`` (title heading +
+    wrapped header + every wrapped row + optional note). Keep in sync."""
+    h = 0.0
+    title = getattr(block, "title", None)
+    if title:
+        h += _measure_heading_text(title, 2)
+    header = list(getattr(block, "header", []) or [])
+    rows = list(getattr(block, "rows", []) or [])
+    fs = _FS_CELL
+    widths = _col_widths(header, rows)
+    if header:
+        h += _row_height_in(header, widths, fs)
+    for r in rows:
+        h += _row_height_in(r, widths, fs)
+    note = getattr(block, "note", None)
+    if note:
+        nlines = tl.wrap(model._safe_str(note),
+                         tl.chars_per_line(_USABLE_W, _FS_NOTE))
+        h += tl.line_height_in(_FS_NOTE) * len(nlines) + 0.05
+    return h + _GAP
+
+
 def _measure_block(st: _PptxState, block) -> float:
     kind = getattr(block, "kind", "")
     try:
@@ -639,9 +688,10 @@ def _measure_block(st: _PptxState, block) -> float:
             lines = tl.wrap(getattr(block, "text", ""),
                             tl.chars_per_line(_USABLE_W, _FS_NOTE))
             return tl.line_height_in(_FS_NOTE) * len(lines) + 0.05 + _GAP
-        if kind in ("kv_table", "data_table"):
-            rows = getattr(block, "rows", []) or []
-            return (tl.line_height_in(_FS_CELL) + 0.10) * (len(rows) + 1) + _GAP
+        if kind == "kv_table":
+            return _measure_kv_table(block)
+        if kind == "data_table":
+            return _measure_data_table(block)
         if kind == "group":
             return sum(_measure_block(st, b)
                        for b in (getattr(block, "blocks", []) or []))
@@ -664,10 +714,14 @@ def _shrink_group_figures(st: _PptxState, blocks: list, avail_full: float) -> No
                    if getattr(b, "kind", "") not in ("figure", "image"))
     fig_overhead = tl.line_height_in(_FS_NOTE) + 0.05 + 0.05 + _GAP
     budget = avail_full - nonfig_h - 0.10 * len(fig_blocks)
-    if budget <= 1.0:
+    # Low thresholds: a 16:9 slide is short, so a content-heavy column (cardinality
+    # table + top-k + chart) only fits if the chart is allowed to shrink small.
+    # Prefer a small-but-present chart on the SAME slide over splitting the column
+    # across slides (matches the PDF renderer's keep-together philosophy).
+    if budget <= 0.6:
         return  # not enough room to keep together; let it flow (degrade).
     per = budget / len(fig_blocks) - fig_overhead
-    if per <= 0.8:
+    if per <= 0.35:
         return
     for fb in fig_blocks:
         cur = getattr(fb, "height_in", None)
@@ -675,12 +729,90 @@ def _shrink_group_figures(st: _PptxState, blocks: list, avail_full: float) -> No
                         if isinstance(cur, (int, float)) and cur > 0 else per)
 
 
+# Minimum height (inches) reserved for a figure inside a keep-together group on
+# the short 16:9 slide. When a high-cardinality column's table(s) would otherwise
+# leave no room, the data table is trimmed (with an honest note) so the chart
+# stays on the SAME slide next to its table instead of spilling to the next one.
+_GROUP_MIN_FIG_H = 1.3
+
+
+def _trim_data_table_to_budget(block, budget: float):
+    """Return a copy of a DataTable whose rows fit within ``budget`` inches.
+
+    Keeps the title, header, as many leading rows as fit (at least one) and an
+    honest note reporting how many of the original rows are shown. NEVER mutates
+    the original block — the same Chapter blocks are rendered by the PDF renderer,
+    which keeps the full table (an A5 page fits it)."""
+    header = list(getattr(block, "header", []) or [])
+    rows = list(getattr(block, "rows", []) or [])
+    title = getattr(block, "title", None)
+    fs = _FS_CELL
+    widths = _col_widths(header, rows)
+    fixed = 0.0
+    if title:
+        fixed += _measure_heading_text(title, 2)
+    if header:
+        fixed += _row_height_in(header, widths, fs)
+    note_h = tl.line_height_in(_FS_NOTE) + 0.05
+    avail_rows = budget - fixed - note_h - _GAP
+    kept = []
+    used = 0.0
+    for r in rows:
+        rh = _row_height_in(r, widths, fs)
+        if used + rh > avail_rows and kept:
+            break
+        kept.append(r)
+        used += rh
+    if len(kept) >= len(rows):
+        return block  # already fits; keep the original (with its own note).
+    note = (f"top {len(kept)} de {len(rows)} categorías mostradas "
+            "(recortado para caber en el slide; el PDF muestra más)")
+    return model.DataTable(header=header, rows=kept, title=title, note=note)
+
+
+def _fit_group_blocks(st: _PptxState, blocks: list, avail_full: float) -> list:
+    """Return a slide-fitting copy of a keep-together group's blocks.
+
+    On the short 16:9 slide a high-cardinality column's top-k table plus its
+    chart can overflow. Reserve ``_GROUP_MIN_FIG_H`` for the (later shrunk) figure
+    and trim the data table(s) to what is left, so every column keeps its chart
+    next to its table on ONE slide. No-op when the group has no figure+table pair
+    (e.g. id-like columns already drop the top-k upstream, or it already fits)."""
+    has_fig = any(getattr(b, "kind", "") in ("figure", "image") for b in blocks)
+    tbls = [b for b in blocks if getattr(b, "kind", "") == "data_table"]
+    if not (has_fig and tbls):
+        return blocks
+    fixed_h = sum(_measure_block(st, b) for b in blocks
+                  if getattr(b, "kind", "") not in ("figure", "image",
+                                                    "data_table"))
+    tables_h = sum(_measure_block(st, b) for b in tbls)
+    budget_tables = avail_full - fixed_h - _GROUP_MIN_FIG_H
+    if tables_h <= budget_tables:
+        return blocks  # already fits next to a min-height figure; leave intact.
+    out = []
+    for b in blocks:
+        if getattr(b, "kind", "") != "data_table":
+            out.append(b)
+            continue
+        trimmed = _trim_data_table_to_budget(b, max(budget_tables, 0.8))
+        out.append(trimmed)
+        budget_tables -= _measure_data_table(trimmed)
+    return out
+
+
 def _place_group(st: _PptxState, block) -> None:
     """Render a keep-together Group: move it whole to the next slide if needed."""
     blocks = getattr(block, "blocks", []) or []
     if not blocks:
         return
+    # Opt-in slide break: start this group on a fresh slide unless the current one
+    # is still empty (so a chapter can give each unit its own slide).
+    if getattr(block, "page_break_before", False) and st.y > _CONTENT_TOP + 1e-6:
+        _new_slide(st, cont=True)
     avail_full = _CONTENT_BOTTOM - _CONTENT_TOP
+    # Trim oversized tables first (keeps the chart on the same slide), then shrink
+    # the figure to share the remaining room.
+    blocks = _fit_group_blocks(st, blocks, avail_full)
     _shrink_group_figures(st, blocks, avail_full)
     total = sum(_measure_block(st, b) for b in blocks)
     if total <= avail_full:

python/functions/datascience/extract_null_mask.md

@@ -0,0 +1,97 @@
+---
+name: extract_null_mask
+kind: function
+lang: py
+domain: datascience
+version: "1.0.0"
+purity: impure
+signature: "def extract_null_mask(query_fn, table: str, columns: list, max_rows: int = 5000) -> dict"
+description: "Extrae la mascara de nulos (1=falta / 0=presente) de una muestra de filas de una tabla, una lista 0/1 por columna alineada por fila, para alimentar el capitulo de calidad / patron de nulos de AutomaticEDA sin que el capitulo toque la base de datos. Recibe un lector read-only inyectado `query_fn(sql) -> dict` (mismo contrato que duckdb_query_readonly / pg_query / el `_q` de profile_table) y NO abre ninguna conexion por su cuenta. Construye UNA sola query que proyecta por cada columna `CASE WHEN \"col\" IS NULL THEN 1 ELSE 0 END` con identificadores escapados y LIMIT. Devuelve dict dict-no-throw: columns (efectivamente leidas, en orden), mask (lista int 0/1 por columna, misma longitud todas) y n. Una celda None se cuenta defensivamente como 1 (falta)."
+tags: [eda, nulls, missing, datascience, automatic-eda, extraction, read-only, duckdb, postgres, python]
+uses_functions: []
+uses_types: []
+returns: []
+returns_optional: false
+error_type: "error_go_core"
+imports: []
+params:
+  - name: query_fn
+    desc: "callable lector read-only del backend activo. Recibe un string SQL y devuelve un dict {'status':'ok','rows':[{col:val,...},...]} (mismo contrato que duckdb_query_readonly o el `_q` de profile_table). NO se abre ninguna conexion dentro de la funcion: toda la lectura pasa por query_fn. Si es None -> error."
+  - name: table
+    desc: "nombre de la tabla de la que muestrear la mascara de nulos. Se escapa con comillas dobles en la query. Vacio o None -> status error."
+  - name: columns
+    desc: "lista de nombres de columna a evaluar. Cada una produce una entrada en `mask` con una lista 0/1 paralela por fila (1=IS NULL, 0=presente). Cada nombre se escapa con comillas dobles. Vacia o None -> status error."
+  - name: max_rows
+    desc: "limite de filas a muestrear (clausula LIMIT). Default 5000. Protege frente a tablas enormes; con LIMIT obtienes el primer tramo, no un muestreo uniforme."
+output: "dict (nunca lanza). En exito: {'status':'ok','table':str,'columns':[str,...] (en orden),'mask':{col:[int 0/1,...],...} (1=falta/IS NULL, 0=presente; todas las listas con misma longitud = n),'n':int}. En error (sin lanzar): {'status':'error','error':str,'table':str,'columns':[],'mask':{},'n':0}. Errores: query_fn None, table vacia, columns vacia, o query_fn devuelve status!='ok' (se propaga su error)."
+tested: true
+tests: ["test_golden_mask_alineada", "test_celda_none_cuenta_como_falta", "test_columns_vacia_status_error", "test_query_fn_status_error_propaga", "test_query_fn_none_da_error_sin_reventar", "test_sql_contiene_case_y_limit"]
+test_file_path: "python/functions/datascience/extract_null_mask_test.py"
+file_path: "python/functions/datascience/extract_null_mask.py"
+---
+
+## Ejemplo
+
+```python
+import sys, os
+sys.path.insert(0, os.path.join("python", "functions"))
+from datascience.extract_null_mask import extract_null_mask
+from infra import duckdb_query_readonly
+
+# El lector read-only se inyecta como closure (igual que el `_q` de profile_table).
+db = "data/clientes.duckdb"
+def _q(sql):
+    return duckdb_query_readonly(db, sql)
+
+res = extract_null_mask(_q, "clientes", ["email", "telefono", "edad"])
+# res == {
+#   "status": "ok",
+#   "table": "clientes",
+#   "columns": ["email", "telefono", "edad"],
+#   "mask": {
+#     "email":    [0, 0, 1, 0, ...],   # fila 2 sin email
+#     "telefono": [1, 0, 1, 0, ...],
+#     "edad":     [0, 0, 0, 1, ...],
+#   },
+#   "n": 5000,
+# }
+
+# % de nulos por columna a partir de la muestra:
+pct = {c: 100 * sum(bits) / max(res["n"], 1) for c, bits in res["mask"].items()}
+
+# Se entrega al capitulo de calidad sin que este toque la BD:
+ctx = {"null_mask": res}
+```
+
+## Cuando usarla
+
+Cuando el capitulo de calidad / patron de nulos de AutomaticEDA necesita saber
+DONDE faltan los valores (no solo cuantos) y NO debe abrir la base de datos por
+su cuenta: extraes aqui la mascara 0/1 por columna alineada por fila y se la pasas
+en `ctx['null_mask']`. Usala siempre que quieras detectar co-ocurrencia de nulos
+(filas que fallan en varias columnas a la vez), calcular el % de nulos sobre una
+muestra, o pintar un heatmap de missingness reutilizando un unico lector read-only
+inyectado, en vez de hacer N `COUNT(*) WHERE col IS NULL` por separado.
+
+## Gotchas
+
+- **Impura**: lee de la base de datos a traves de `query_fn`. No abre conexiones
+  por su cuenta — depende por completo del lector inyectado. Sigue el estilo
+  dict-no-throw del grupo `eda`: nunca lanza; ante cualquier fallo devuelve
+  `{"status":"error","error":...}` con `columns=[]`, `mask={}`, `n=0`.
+- **`error_type` en el frontmatter es `error_go_core` por convencion del registry**
+  (toda funcion impura debe declararlo y el indexer lo exige), pero el codigo
+  NO lanza esa excepcion: degrada al dict de error. Es metadata, no comportamiento.
+- **Muestra, no censo**: con `LIMIT max_rows` obtienes el primer tramo de filas que
+  devuelva el backend, no un muestreo uniforme ni la tabla entera. El % de nulos
+  derivado es una estimacion sobre esa muestra; para el conteo exacto usa un
+  agregado `COUNT(*)`/`COUNT(col)` aparte.
+- **Alineacion por fila**: `mask[col][i]` corresponde a la misma fila `i` que
+  `mask[otra_col][i]`. Todas las listas tienen longitud `n`, asi que puedes cruzar
+  columnas por indice (co-ocurrencia de nulos) sin re-alinear.
+- **Defensa None -> 1**: el SQL ya devuelve 0/1, pero si una celda llega como `None`
+  (CASE no aplicado, columna ausente en la fila, backend que nulifica) se cuenta
+  como 1 (falta). Un valor inesperado no convertible a int se trata como presente (0).
+- **No loguear los datos crudos**: aunque `mask` es solo 0/1, los nombres de columna
+  pueden revelar el esquema. En trazas usa `n` y el numero de columnas, no el dict
+  completo.

python/functions/datascience/extract_null_mask.py

@@ -0,0 +1,101 @@
+"""extract_null_mask — extrae la mascara de nulos (1=falta / 0=presente) de una tabla.
+
+Lector read-only inyectado: recibe `query_fn(sql) -> dict` con el mismo contrato
+que duckdb_query_readonly / pg_query (y que el `_q` de profile_table):
+`{"status": "ok", "rows": [{col: val, ...}, ...]}`. Esta funcion NO abre ninguna
+conexion por su cuenta — solo usa `query_fn`. Construye UNA sola query que, por
+cada columna pedida, evalua `CASE WHEN "col" IS NULL THEN 1 ELSE 0 END` y devuelve
+una muestra de filas con esos bits. El resultado es un dict `mask` con una lista
+0/1 por columna, alineada por fila (1 = el valor falta / IS NULL, 0 = presente),
+listo para alimentar el capitulo de calidad / patron de nulos de AutomaticEDA sin
+que el capitulo toque la base de datos.
+
+Estilo dict-no-throw del grupo `eda`: nunca lanza; captura cualquier excepcion y
+degrada a `{"status": "error", "error": str, ...}`.
+"""
+
+
+def _to_bit(value):
+    """Coacciona el valor 0/1 del CASE a int de forma defensiva.
+
+    El SQL ya devuelve 0 (presente) o 1 (falta). Por si una celda llega como None
+    (el CASE no se aplico o el backend la nulifico), se cuenta como 1 (falta). El
+    resto se reduce a int: un entero distinto de 0 cuenta como 1 (falta), 0 como
+    presente. Un valor no convertible se trata como presente (0) — nunca lanza.
+    """
+    if value is None:
+        return 1
+    try:
+        return 1 if int(value) != 0 else 0
+    except (TypeError, ValueError):
+        return 0
+
+
+def extract_null_mask(query_fn, table, columns, max_rows=5000):
+    """Extrae la mascara de nulos (1=falta / 0=presente) de una muestra de la tabla.
+
+    Args:
+        query_fn: callable lector read-only del backend activo. Recibe un string
+            SQL y devuelve un dict {"status": "ok", "rows": [{col: val, ...}]}
+            (mismo contrato que duckdb_query_readonly / el `_q` de profile_table).
+            No se abre ninguna conexion aqui: toda la lectura pasa por query_fn.
+        table: nombre de la tabla. Se escapa con comillas dobles en la query.
+        columns: lista de nombres de columna a evaluar. Cada una produce una
+            entrada en `mask` con una lista 0/1 paralela por fila. Vacia o None ->
+            status error.
+        max_rows: limite de filas a muestrear (clausula LIMIT). Default 5000.
+
+    Returns:
+        dict (nunca lanza):
+            {
+              "status": "ok" | "error",
+              "error": str,                 # solo si status == "error"
+              "table": str,
+              "columns": [str, ...],        # columnas efectivamente leidas, en orden
+              "mask": {col: [int 0/1, ...], ...},  # alineada por fila, 1=falta, 0=presente
+              "n": int                      # nº de filas muestreadas
+            }
+        Todas las listas de `mask` tienen la misma longitud (= n).
+    """
+    base = {"status": "ok", "table": table, "columns": [], "mask": {}, "n": 0}
+    try:
+        if query_fn is None:
+            return {**base, "status": "error", "error": "query_fn es None"}
+        if not table:
+            return {**base, "status": "error", "error": "table es obligatorio"}
+        if not columns:
+            return {**base, "status": "error", "error": "columns vacío"}
+
+        # Identificadores escapados con comillas dobles (como hace profile_table)
+        # para tolerar nombres con mayusculas/espacios/palabras reservadas. Cada
+        # columna se proyecta como su propio bit IS NULL conservando el alias.
+        select_sql = ", ".join(
+            f'(CASE WHEN "{c}" IS NULL THEN 1 ELSE 0 END) AS "{c}"' for c in columns
+        )
+        sql = f'SELECT {select_sql} FROM "{table}" LIMIT {int(max_rows)}'
+
+        q = query_fn(sql)
+        if not isinstance(q, dict) or q.get("status") != "ok":
+            err = (
+                q.get("error", "query_fn fallo")
+                if isinstance(q, dict)
+                else "query_fn no devolvio un dict"
+            )
+            return {**base, "status": "error", "error": err}
+
+        rows = q.get("rows", []) or []
+        mask = {c: [] for c in columns}
+        for row in rows:
+            for c in columns:
+                # row.get tolera filas que no traigan la columna (None -> falta).
+                mask[c].append(_to_bit(row.get(c) if isinstance(row, dict) else None))
+
+        return {
+            "status": "ok",
+            "table": table,
+            "columns": list(columns),
+            "mask": mask,
+            "n": len(rows),
+        }
+    except Exception as e:  # noqa: BLE001 - dict-no-throw: degradar, nunca lanzar
+        return {**base, "status": "error", "error": str(e)}

python/functions/datascience/extract_null_mask_test.py

@@ -0,0 +1,116 @@
+"""Tests para extract_null_mask.
+
+No usa DuckDB real: inyecta un query_fn FAKE (closure) que devuelve filas
+predefinidas (simulando el SELECT de bits 0/1) y, opcionalmente, captura el SQL
+recibido para verificar la query generada (CASE WHEN ... IS NULL + LIMIT). Asi el
+test es autocontenido y no depende de ningun backend.
+"""
+
+import os
+import sys
+
+sys.path.insert(0, os.path.dirname(__file__))
+
+from extract_null_mask import extract_null_mask
+
+
+def _fake_query(rows, captured=None, status="ok", error=None):
+    """Crea un query_fn FAKE.
+
+    `captured` (lista opcional) recibe el SQL ejecutado para poder inspeccionarlo.
+    `status`/`error` permiten simular un fallo del backend.
+    """
+
+    def _q(sql):
+        if captured is not None:
+            captured.append(sql)
+        if status != "ok":
+            return {"status": "error", "error": error or "boom"}
+        return {"status": "ok", "rows": rows}
+
+    return _q
+
+
+def test_golden_mask_alineada():
+    """Golden: mask 0/1 por columna alineada por fila, n correcto, status ok."""
+    # Cada fila simula el SELECT (CASE WHEN col IS NULL THEN 1 ELSE 0 END) AS col.
+    rows = [
+        {"email": 0, "telefono": 1, "edad": 0},
+        {"email": 0, "telefono": 0, "edad": 1},
+        {"email": 1, "telefono": 1, "edad": 0},
+    ]
+    res = extract_null_mask(_fake_query(rows), "clientes", ["email", "telefono", "edad"])
+    assert res["status"] == "ok"
+    assert res["table"] == "clientes"
+    assert res["columns"] == ["email", "telefono", "edad"]
+    assert res["n"] == 3
+    assert res["mask"]["email"] == [0, 0, 1]
+    assert res["mask"]["telefono"] == [1, 0, 1]
+    assert res["mask"]["edad"] == [0, 1, 0]
+    # Todas las listas con la misma longitud.
+    assert all(len(v) == res["n"] for v in res["mask"].values())
+
+
+def test_celda_none_cuenta_como_falta():
+    """Una celda None se cuenta defensivamente como 1 (falta)."""
+    rows = [
+        {"email": 0, "telefono": None},
+        {"email": None, "telefono": 1},
+        {"email": 1, "telefono": 0},
+    ]
+    res = extract_null_mask(_fake_query(rows), "clientes", ["email", "telefono"])
+    assert res["status"] == "ok"
+    assert res["mask"]["email"] == [0, 1, 1]
+    assert res["mask"]["telefono"] == [1, 1, 0]
+    assert res["n"] == 3
+
+
+def test_columns_vacia_status_error():
+    """columns vacia -> status error con columns/mask/n vacios."""
+    res = extract_null_mask(_fake_query([]), "clientes", [])
+    assert res["status"] == "error"
+    assert "columns" in res["error"]
+    assert res["table"] == "clientes"
+    assert res["columns"] == []
+    assert res["mask"] == {}
+    assert res["n"] == 0
+
+
+def test_query_fn_status_error_propaga():
+    """query_fn que devuelve status != ok -> se propaga como error, mask {}."""
+    res = extract_null_mask(
+        _fake_query([], status="error", error="db locked"),
+        "clientes",
+        ["email"],
+    )
+    assert res["status"] == "error"
+    assert "db locked" in res["error"]
+    assert res["mask"] == {}
+    assert res["n"] == 0
+
+
+def test_query_fn_none_da_error_sin_reventar():
+    """query_fn None -> error degradado, sin excepcion."""
+    res = extract_null_mask(None, "clientes", ["email"])
+    assert res["status"] == "error"
+    assert res["columns"] == []
+    assert res["mask"] == {}
+    assert res["n"] == 0
+
+
+def test_sql_contiene_case_y_limit():
+    """La query genera un CASE WHEN IS NULL por columna escapada + LIMIT sobre la tabla."""
+    captured = []
+    rows = [{"email": 0}]
+    extract_null_mask(
+        _fake_query(rows, captured),
+        "clientes_tbl",
+        ["email"],
+        max_rows=123,
+    )
+    assert len(captured) == 1
+    sql = captured[0]
+    assert 'CASE WHEN "email" IS NULL THEN 1 ELSE 0 END' in sql
+    assert 'AS "email"' in sql
+    assert 'FROM "clientes_tbl"' in sql
+    assert "LIMIT 123" in sql

python/functions/datascience/missingness_corr_heatmap_figure.md

@@ -0,0 +1,103 @@
+---
+id: missingness_corr_heatmap_figure_py_datascience
+name: missingness_corr_heatmap_figure
+kind: function
+lang: py
+domain: datascience
+version: "1.0.0"
+purity: impure
+signature: "def missingness_corr_heatmap_figure(matrix, labels, title=\"Co-ocurrencia de ausencias\") -> \"matplotlib.figure.Figure\""
+description: "Construye una figura matplotlib (heatmap) de la matriz NxN de correlación de ausencias entre columnas: +1 = dos columnas suelen ser nulas a la vez, -1 = cuando una falta la otra está presente, 0 = ausencias independientes. Usa ax.imshow con coolwarm fijado a [-1,1], ticks con los labels truncados (X rotados 45º), colorbar y anota el valor de cada celda si N<=12. Devuelve un matplotlib.figure.Figure listo para rasterizar por el renderer del informe EDA (capítulo de datos faltantes). Backend Agg sin pyplot global; defensivo ante matrix/labels vacíos o celdas no numéricas (nunca lanza)."
+tags: [eda, missing, missingness, correlation, heatmap, matplotlib, figure, visualization, datascience, impure]
+uses_functions: []
+uses_types: []
+returns: []
+returns_optional: false
+error_type: "error_go_core"
+imports: [matplotlib]
+example: |
+  from datascience.missingness_corr_heatmap_figure import missingness_corr_heatmap_figure
+  matrix = [
+      [1.0, 0.82, -0.10],
+      [0.82, 1.0, 0.05],
+      [-0.10, 0.05, 1.0],
+  ]
+  labels = ["telefono", "movil", "email"]
+  fig = missingness_corr_heatmap_figure(matrix, labels, title="Co-ocurrencia de ausencias")
+tested: true
+tests:
+  - "test_returns_figure_with_axes"
+  - "test_empty_matrix_does_not_raise_and_returns_figure"
+  - "test_empty_labels_returns_message_figure"
+  - "test_large_matrix_omits_annotations"
+  - "test_ragged_and_non_numeric_cells_are_handled"
+test_file_path: "python/functions/datascience/missingness_corr_heatmap_figure_test.py"
+file_path: "python/functions/datascience/missingness_corr_heatmap_figure.py"
+params:
+  - name: matrix
+    desc: "Lista de listas (NxN) de floats en [-1,1]: la correlación de ausencias por pares de columnas. Puede venir vacía. Filas de longitud desigual se toleran (se rellenan/recortan a N); celdas None, NaN o no numéricas se coercen a 0.0. No se muta el original."
+  - name: labels
+    desc: "Lista de N nombres de columna, paralela a matrix. Puede venir vacía (devuelve figura \"sin columnas con ausencia variable\"). Se truncan a ~14 chars con elipsis para los ticks; los originales no se mutan."
+  - name: title
+    desc: "Título de la figura. Se trunca a ~60 chars con elipsis si es muy largo. Default \"Co-ocurrencia de ausencias\"."
+output: "Un matplotlib.figure.Figure (figsize 6.4x5.2, dpi 150) con un Axes heatmap (imshow vmin=-1, vmax=1, cmap coolwarm) más una colorbar etiquetada \"correlación de ausencias\". Ticks en ambos ejes con los labels truncados (X rotados 45º). Si N<=12 cada celda lleva su valor numérico anotado (texto blanco sobre celdas saturadas, oscuro sobre pálidas); con N grande se omiten las anotaciones para no saturar. Si matrix o labels vienen vacíos devuelve una Figure con texto centrado \"sin columnas con ausencia variable\"; cualquier error inesperado se captura y devuelve una Figure con el mensaje de error (nunca lanza). El caller rasteriza/cierra la figura; la función no la muestra ni la guarda."
+---
+
+## Ejemplo
+
+```python
+from datascience.missingness_corr_heatmap_figure import missingness_corr_heatmap_figure
+
+# Correlación de ausencias entre 3 columnas de contacto:
+# telefono y movil tienden a faltar juntos (0.82); email es casi independiente.
+matrix = [
+    [1.00, 0.82, -0.10],
+    [0.82, 1.00,  0.05],
+    [-0.10, 0.05, 1.00],
+]
+labels = ["telefono", "movil", "email"]
+
+fig = missingness_corr_heatmap_figure(
+    matrix,
+    labels,
+    title="Co-ocurrencia de ausencias",
+)
+
+# El renderer del informe lo rasteriza; aquí solo persistimos para inspección.
+fig.savefig("/tmp/missingness_heatmap.png")
+```
+
+## Cuando usarla
+
+Úsala en el capítulo de datos faltantes de un informe EDA cuando quieras ver de
+un vistazo qué columnas faltan juntas (mismo formulario sin rellenar, mismo
+proceso roto) frente a columnas cuyas ausencias son independientes. Pásale la
+matriz de correlación de ausencias (calculada sobre la máscara de nulos, p. ej.
+`df.isnull().corr()`) restringida a las columnas que de verdad tienen ausencia
+variable, junto con sus nombres. Es la pareja "estructura" del ranking de % de
+nulos: las barras dicen *cuánto* falta cada columna, este heatmap dice *si las
+ausencias están relacionadas* entre columnas.
+
+## Gotchas
+
+- **Impura por matplotlib.** Toca la maquinaria de render. Usa el backend `Agg`
+  y la API orientada a objetos `Figure`/`add_subplot` — NUNCA `pyplot.*` aquí,
+  para no tocar el estado global ni filtrar figuras entre llamadas. `pyplot` NO
+  es thread-safe; esta función evita ese riesgo construyendo el `Figure`
+  directamente, así que es segura de llamar en bucle desde el renderer.
+- **El caller cierra la figura.** Devuelve el `Figure` pero no lo muestra ni lo
+  guarda. Quien la consume debe rasterizarla y luego liberarla
+  (`matplotlib.pyplot.close(fig)`) para no acumular memoria en lotes grandes.
+- **Escala de color fija en [-1, 1].** `vmin=-1`, `vmax=1` están fijados a
+  propósito para que el color sea comparable entre informes y entre columnas. No
+  se autoescala al rango real de la matriz; valores fuera de `[-1, 1]` se
+  saturan al extremo del colormap.
+- **Anotaciones solo con N<=12.** Por encima de 12 columnas el grid de números
+  se vuelve ilegible y se omite; queda solo el color + la colorbar. Filtra a las
+  columnas con ausencia variable antes de llamar para no llegar a matrices
+  enormes.
+- **Defensiva, nunca lanza.** `matrix=[]`, `labels=[]`, filas cortas, celdas
+  `None`/`NaN`/no numéricas o cualquier error inesperado se manejan sin propagar:
+  en el peor caso devuelve una `Figure` con "sin columnas con ausencia variable"
+  o con el texto del error. No envuelvas la llamada en try/except por miedo a un
+  raise — no lo hay.

python/functions/datascience/missingness_corr_heatmap_figure.py

@@ -0,0 +1,158 @@
+"""Impure EDA helper: heatmap of missingness co-occurrence (`eda` group).
+
+Builds a matplotlib heatmap of the pairwise missingness correlation matrix of a
+dataset: a value near ``+1`` means two columns tend to be null together, near
+``-1`` means when one is null the other tends to be present, and ``0`` means
+their absences are independent. Returns a ready-to-rasterize
+``matplotlib.figure.Figure``; it never shows nor saves it.
+
+Impure because it touches matplotlib's rendering machinery. It uses the headless
+Agg backend and the object-oriented ``Figure`` API (no ``pyplot``) so it leaks no
+global state and is safe to call repeatedly from a report renderer.
+"""
+
+import matplotlib
+
+matplotlib.use("Agg")
+
+from matplotlib.figure import Figure  # noqa: E402
+
+# Muted gray for secondary text (no-data / fallback messages).
+_MUTED_TEXT = "#5f6b7a"
+# Soft red for the error fallback message (kept readable, not alarming).
+_ERROR_TEXT = "#b00020"
+
+
+def _truncate(text, width: int = 14) -> str:
+    """Truncate ``text`` to ``width`` chars, appending an ellipsis if cut."""
+    s = "" if text is None else str(text)
+    if len(s) <= width:
+        return s
+    if width <= 1:
+        return s[:width]
+    return s[: width - 1] + "…"
+
+
+def _message_figure(message: str, color: str = _MUTED_TEXT) -> "Figure":
+    """Return a fallback ``Figure`` carrying a single centered message."""
+    fig = Figure(figsize=(6.4, 4.0), dpi=150)
+    ax = fig.add_subplot(111)
+    ax.axis("off")
+    ax.text(
+        0.5,
+        0.5,
+        message,
+        ha="center",
+        va="center",
+        fontsize=12,
+        color=color,
+        wrap=True,
+        transform=ax.transAxes,
+    )
+    fig.tight_layout()
+    return fig
+
+
+def missingness_corr_heatmap_figure(
+    matrix,
+    labels,
+    title: str = "Co-ocurrencia de ausencias",
+) -> "matplotlib.figure.Figure":
+    """Build a heatmap figure of a missingness correlation matrix.
+
+    Renders an ``NxN`` matrix of missingness correlations in ``[-1, 1]`` with a
+    diverging ``coolwarm`` colormap (fixed ``vmin=-1``, ``vmax=1`` so the color
+    scale is comparable across reports). Both axes are tick-labelled with the
+    column names (truncated to ~14 chars; the X labels rotated 45°). A colorbar
+    is attached. When the matrix is small (``N <= 12``) each cell is annotated
+    with its numeric value; for larger matrices the annotations are omitted to
+    avoid an unreadable grid.
+
+    The function is fully defensive: empty/ragged/non-numeric input never raises.
+    When there is nothing valid to draw it returns a ``Figure`` carrying a
+    centered "sin columnas con ausencia variable" message, and any unexpected
+    error is caught and turned into a fallback ``Figure`` carrying the error text.
+
+    Args:
+        matrix: List of lists (``NxN``) of floats in ``[-1, 1]`` — the pairwise
+            missingness correlation. May be empty; rows of unequal length are
+            tolerated by treating the matrix as invalid only when it is empty or
+            its label count does not match. Non-numeric/``None`` cells are
+            coerced to ``0.0``.
+        labels: List of ``N`` column names, parallel to ``matrix``. May be empty.
+            Truncated for display; the originals are not mutated.
+        title: Figure title. Default "Co-ocurrencia de ausencias".
+
+    Returns:
+        A ``matplotlib.figure.Figure`` with a single heatmap Axes plus a
+        colorbar. The caller is responsible for rasterizing/closing it.
+    """
+    try:
+        # --- Validate shape: need a non-empty square-ish matrix with labels.
+        if (
+            not isinstance(matrix, (list, tuple))
+            or not isinstance(labels, (list, tuple))
+            or len(matrix) == 0
+            or len(labels) == 0
+        ):
+            return _message_figure("sin columnas con ausencia variable")
+
+        n = len(labels)
+        # Build a clean NxN grid: coerce each cell to float, default 0.0, pad/clip
+        # rows so a ragged input never crashes imshow.
+        grid = []
+        for i in range(n):
+            row_src = matrix[i] if i < len(matrix) else []
+            if not isinstance(row_src, (list, tuple)):
+                row_src = []
+            row = []
+            for j in range(n):
+                cell = row_src[j] if j < len(row_src) else 0.0
+                try:
+                    val = float(cell)
+                except (TypeError, ValueError):
+                    val = 0.0
+                if val != val:  # NaN guard.
+                    val = 0.0
+                row.append(val)
+            grid.append(row)
+
+        fig = Figure(figsize=(6.4, 5.2), dpi=150)
+        ax = fig.add_subplot(111)
+
+        im = ax.imshow(grid, vmin=-1, vmax=1, cmap="coolwarm", aspect="equal")
+
+        short = [_truncate(lab, 14) for lab in labels]
+        ax.set_xticks(range(n))
+        ax.set_yticks(range(n))
+        ax.set_xticklabels(short, rotation=45, ha="right", fontsize=8)
+        ax.set_yticklabels(short, fontsize=8)
+
+        # Annotate each cell only when the grid is small enough to stay legible.
+        if n <= 12:
+            for i in range(n):
+                for j in range(n):
+                    val = grid[i][j]
+                    # White text over saturated (dark) cells, dark over pale.
+                    txt_color = "white" if abs(val) >= 0.55 else "#202020"
+                    ax.text(
+                        j,
+                        i,
+                        f"{val:.2f}",
+                        ha="center",
+                        va="center",
+                        fontsize=7,
+                        color=txt_color,
+                    )
+
+        cbar = fig.colorbar(im, ax=ax, fraction=0.046, pad=0.04)
+        cbar.ax.tick_params(labelsize=8)
+        cbar.set_label("correlación de ausencias", fontsize=8)
+
+        if title:
+            ax.set_title(_truncate(title, 60), fontsize=12, loc="center", pad=10)
+
+        fig.tight_layout()
+        return fig
+    except Exception as exc:  # noqa: BLE001 — never raise from a figure builder.
+        return _message_figure(f"error al dibujar heatmap: {exc}", color=_ERROR_TEXT)

python/functions/datascience/missingness_corr_heatmap_figure_test.py

@@ -0,0 +1,62 @@
+"""Tests para missingness_corr_heatmap_figure (heatmap de ausencias, grupo eda).
+
+Usa el backend Agg sin pyplot; no muestra ni guarda figuras. Cada test cierra
+explícitamente la Figure construida (matplotlib.pyplot.close) para no acumular
+estado entre tests.
+"""
+
+import matplotlib
+
+matplotlib.use("Agg")
+
+import matplotlib.pyplot as plt  # noqa: E402
+from matplotlib.figure import Figure  # noqa: E402
+
+from missingness_corr_heatmap_figure import missingness_corr_heatmap_figure
+
+
+def _identity_matrix(n):
+    """Matriz NxN con diagonal 1.0 y resto 0.0 (correlación de ausencias)."""
+    return [[1.0 if i == j else 0.0 for j in range(n)] for i in range(n)]
+
+
+def test_returns_figure_with_axes():
+    matrix = [[1.0, 0.3, -0.2], [0.3, 1.0, 0.5], [-0.2, 0.5, 1.0]]
+    labels = ["edad", "ingresos", "ciudad"]
+    fig = missingness_corr_heatmap_figure(matrix, labels, title="ausencias")
+    assert isinstance(fig, Figure)
+    # Heatmap (>=1 axes) + colorbar añade su propio Axes -> al menos 1.
+    assert len(fig.axes) >= 1
+    plt.close(fig)
+
+
+def test_empty_matrix_does_not_raise_and_returns_figure():
+    fig = missingness_corr_heatmap_figure([], [], title="vacía")
+    assert isinstance(fig, Figure)
+    assert len(fig.axes) >= 1
+    plt.close(fig)
+
+
+def test_empty_labels_returns_message_figure():
+    fig = missingness_corr_heatmap_figure([[1.0]], [], title="sin labels")
+    assert isinstance(fig, Figure)
+    plt.close(fig)
+
+
+def test_large_matrix_omits_annotations():
+    n = 16
+    fig = missingness_corr_heatmap_figure(
+        _identity_matrix(n), [f"col_{i}" for i in range(n)]
+    )
+    assert isinstance(fig, Figure)
+    assert len(fig.axes) >= 1
+    plt.close(fig)
+
+
+def test_ragged_and_non_numeric_cells_are_handled():
+    # Fila corta + celda None + celda string -> se rellenan/coercen sin lanzar.
+    matrix = [[1.0, None], ["x", 1.0, 0.5]]
+    labels = ["a", "b"]
+    fig = missingness_corr_heatmap_figure(matrix, labels)
+    assert isinstance(fig, Figure)
+    plt.close(fig)

python/functions/datascience/missingness_correlation.md

@@ -0,0 +1,68 @@
+---
+name: missingness_correlation
+kind: function
+lang: py
+domain: datascience
+version: "1.0.0"
+purity: pure
+signature: "def missingness_correlation(null_mask: dict, top_k: int = 20) -> dict"
+description: "Co-ocurrencia de ausencias: nucleo del capitulo de missingness del grupo eda. Recibe la mascara binaria de nulos de una tabla (1 = falta, 0 = presente, alineada por fila) y mide hasta que punto las columnas faltan juntas. Calcula la matriz de correlacion de Pearson entre los vectores binarios de ausencia de las columnas con varianza (al menos un 1 y un 0), mas las cifras de solapamiento de conjuntos por par (co-missing, either-missing, Jaccard). Excluye las columnas constantes en su ausencia (correlacion indefinida) y reporta cuantas. Compone la funcion atomica pearson del registry; no la reimplementa. Lectura defensiva; NUNCA lanza."
+tags: [eda, missingness, correlation, pearson, co-occurrence, jaccard, datascience]
+params:
+  - name: null_mask
+    desc: "dict {col: [int 0/1, ...]} con la mascara de ausencias de la tabla, alineada por fila: 1 = el valor falta en esa fila, 0 = presente. Todas las listas se asumen de la misma longitud (numero de filas). Valores truthy distintos de 0 se tratan como ausencia; entradas no-lista se ignoran sin romper."
+  - name: top_k
+    desc: "Numero maximo de pares a devolver en `pairs`, ordenados por valor absoluto de correlacion descendente. Default 20. Solo limita la lista de pares; la matriz cubre siempre todas las columnas con varianza."
+output: "dict con: columns (columnas con varianza en la ausencia, en orden de entrada); matrix (len(columns) x len(columns) de correlacion de Pearson entre las mascaras binarias, diagonal 1.0); pairs (hasta top_k pares i<j ordenados por |corr| desc, cada uno {a, b, corr, co_missing, either_missing, jaccard} donde co_missing = filas en que ambas faltan, either_missing = filas en que al menos una falta, jaccard = co_missing/either_missing o 0.0 si either_missing=0); n_excluded (nº de columnas con algun nulo pero sin varianza, constantes en la ausencia); excluded_cols (esas columnas en orden de entrada). Si hay <2 columnas con varianza, columns/matrix/pairs van vacios pero n_excluded/excluded_cols se rellenan. NUNCA lanza."
+uses_functions: [pearson_py_datascience]
+uses_types: []
+returns: []
+returns_optional: false
+error_type: ""
+imports: []
+tested: true
+tests: ["test_co_ocurrencia_fuerte_corr_uno_jaccard_uno", "test_ausencias_disjuntas_corr_negativa_jaccard_cero", "test_columna_sin_varianza_se_excluye", "test_menos_de_dos_columnas_con_varianza_vacio_pero_cuenta_excluidas", "test_mask_vacio_todo_vacio", "test_top_k_limita_pares", "test_no_lanza_con_entradas_raras"]
+test_file_path: "python/functions/datascience/missingness_correlation_test.py"
+file_path: "python/functions/datascience/missingness_correlation.py"
+---
+
+## Ejemplo
+
+```python
+import sys, os
+sys.path.insert(0, os.path.join("python", "functions"))
+from datascience.missingness_correlation import missingness_correlation
+
+# Mascara de ausencias de 6 filas. 1 = falta, 0 = presente.
+mask = {
+    "ingresos":  [1, 0, 1, 0, 1, 0],   # falta junto a "deducciones"
+    "deducciones": [1, 0, 1, 0, 1, 0], # mismas filas que "ingresos"
+    "telefono":  [0, 0, 0, 1, 0, 0],   # casi siempre presente
+    "verificado": [1, 1, 1, 1, 1, 1],  # siempre ausente -> constante, excluida
+}
+out = missingness_correlation(mask, top_k=10)
+
+print(out["columns"])        # ['ingresos', 'deducciones', 'telefono']
+print(out["n_excluded"])     # 1
+print(out["excluded_cols"])  # ['verificado']
+
+# El par mas fuerte: ingresos y deducciones faltan siempre juntas.
+top = out["pairs"][0]
+print(top["a"], top["b"], round(top["corr"], 3))  # ingresos deducciones 1.0
+print(top["co_missing"], top["either_missing"], top["jaccard"])  # 3 3 1.0
+```
+
+## Cuando usarla
+
+- Usala en el capitulo de **missingness** de `AutomaticEDA` cuando ya tengas la mascara binaria de nulos por columna y quieras detectar **patrones de ausencia conjunta**: que columnas faltan siempre juntas (posible misma fuente/proceso roto) y cuales faltan de forma independiente.
+- Cuando necesites ordenar los pares de columnas por fuerza de co-ocurrencia (|corr|) para priorizar que bloques de ausencia investigar o imputar juntos.
+- Cuando quieras la cifra de solapamiento de conjuntos (Jaccard, co-missing) ademas de la correlacion lineal, para distinguir "faltan juntas" de "estan presentes juntas".
+- Antes de elegir una estrategia de imputacion: dos columnas con corr de ausencia ~1.0 no aportan informacion independiente sobre por que falta la otra.
+
+## Gotchas
+
+- Funcion pura, sin I/O y determinista. Lectura defensiva: entradas no-dict, columnas no-lista o vacias se ignoran sin lanzar.
+- Solo entran al calculo las columnas con **varianza en la ausencia** (al menos un 1 y al menos un 0). Una columna siempre-presente (todo 0) no aporta ausencia y **no** se cuenta como excluida; una columna siempre-ausente o constante con nulos (todo 1) tiene correlacion indefinida y se excluye, sumando a `n_excluded` / `excluded_cols`.
+- Con menos de 2 columnas con varianza, `columns`/`matrix`/`pairs` quedan vacios pero `n_excluded`/`excluded_cols` se rellenan igual — el caller debe contemplar el caso "sin pares".
+- La correlacion es la de Pearson sobre vectores binarios (equivale al coeficiente phi). El signo importa: corr negativa = las ausencias tienden a ser **complementarias** (cuando una falta, la otra suele estar presente).
+- Asume todas las listas alineadas por fila y de la misma longitud. Si vienen de longitudes distintas, `pearson` opera sobre el solapamiento que permita `zip` y degrada a 0.0 cuando no hay varianza efectiva; alinea la mascara antes de llamar.

python/functions/datascience/missingness_correlation.py

@@ -0,0 +1,120 @@
+"""Co-ocurrencia de ausencias: matriz de correlacion de Pearson entre mascaras de nulos.
+
+Funcion pura del grupo eda, nucleo del capitulo de missingness. Recibe la mascara
+binaria de ausencias de una tabla (1 = falta, 0 = presente, alineada por fila) y
+mide hasta que punto las columnas faltan juntas. Para cada par de columnas con
+varianza en su ausencia calcula la correlacion de Pearson entre los vectores
+binarios, mas las cifras de solapamiento de conjuntos (co-missing, either-missing,
+Jaccard). Compone la funcion atomica `pearson` del registry; no reimplementa la
+correlacion. Lectura defensiva; NUNCA lanza.
+"""
+
+from datascience import pearson
+
+
+def missingness_correlation(null_mask, top_k=20) -> dict:
+    """Correlacion de co-ocurrencia de ausencias entre columnas.
+
+    Args:
+        null_mask: dict {col: [int 0/1, ...]} alineado por fila (1 = el valor
+            falta en esa fila). Todas las listas se asumen de la misma longitud.
+        top_k: numero maximo de pares a devolver, ordenados por |corr| desc.
+
+    Returns:
+        dict con:
+          - columns: columnas con varianza en la ausencia (al menos un 1 y al
+            menos un 0), en orden de entrada.
+          - matrix: matriz len(columns) x len(columns) de correlacion de Pearson
+            entre las mascaras binarias, diagonal 1.0.
+          - pairs: lista de hasta top_k pares (i<j) ordenados por |corr| desc.
+            Cada par: {a, b, corr, co_missing, either_missing, jaccard}.
+          - n_excluded: numero de columnas con algun nulo pero sin varianza
+            (constantes en la ausencia: siempre presentes o siempre ausentes).
+          - excluded_cols: lista de esas columnas (en orden de entrada).
+
+        Si hay menos de 2 columnas con varianza, columns/matrix/pairs van vacios
+        pero n_excluded/excluded_cols se rellenan igualmente. NUNCA lanza.
+    """
+    # Salida base, defensiva ante entradas no-dict.
+    result = {
+        "columns": [],
+        "matrix": [],
+        "pairs": [],
+        "n_excluded": 0,
+        "excluded_cols": [],
+    }
+
+    if not isinstance(null_mask, dict) or not null_mask:
+        return result
+
+    varying = []          # columnas con varianza en la ausencia
+    varying_vecs = []     # sus vectores binarios saneados (floats 0.0/1.0)
+    excluded_cols = []    # columnas con nulos pero sin varianza (constantes)
+
+    for col, raw in null_mask.items():
+        if not isinstance(raw, (list, tuple)):
+            continue
+        # Sanea a 0/1: cualquier valor truthy distinto de 0 cuenta como ausencia.
+        vec = [1 if bool(v) else 0 for v in raw]
+        if not vec:
+            continue
+        ones = sum(vec)
+        zeros = len(vec) - ones
+        if ones > 0 and zeros > 0:
+            varying.append(col)
+            varying_vecs.append([float(v) for v in vec])
+        elif ones > 0:
+            # Tiene nulos pero todos (constante en la ausencia): sin varianza.
+            excluded_cols.append(col)
+        # ones == 0 -> columna siempre presente, sin nulos: no se cuenta como
+        # excluida (no aporta ausencia al analisis de co-ocurrencia).
+
+    result["n_excluded"] = len(excluded_cols)
+    result["excluded_cols"] = excluded_cols
+
+    n = len(varying)
+    if n < 2:
+        return result
+
+    result["columns"] = list(varying)
+
+    # Matriz de correlacion de Pearson, diagonal 1.0.
+    matrix = [[0.0] * n for _ in range(n)]
+    for i in range(n):
+        matrix[i][i] = 1.0
+    for i in range(n):
+        for j in range(i + 1, n):
+            r = pearson(varying_vecs[i], varying_vecs[j])
+            matrix[i][j] = r
+            matrix[j][i] = r
+    result["matrix"] = matrix
+
+    # Pares con cifras de solapamiento de conjuntos.
+    pairs = []
+    for i in range(n):
+        vi = varying_vecs[i]
+        for j in range(i + 1, n):
+            vj = varying_vecs[j]
+            co_missing = 0
+            either_missing = 0
+            for a, b in zip(vi, vj):
+                a_miss = a != 0.0
+                b_miss = b != 0.0
+                if a_miss and b_miss:
+                    co_missing += 1
+                if a_miss or b_miss:
+                    either_missing += 1
+            jaccard = co_missing / either_missing if either_missing > 0 else 0.0
+            pairs.append({
+                "a": varying[i],
+                "b": varying[j],
+                "corr": matrix[i][j],
+                "co_missing": co_missing,
+                "either_missing": either_missing,
+                "jaccard": jaccard,
+            })
+
+    pairs.sort(key=lambda p: abs(p["corr"]), reverse=True)
+    result["pairs"] = pairs[:top_k] if top_k is not None and top_k >= 0 else pairs
+
+    return result

python/functions/datascience/missingness_correlation_test.py

@@ -0,0 +1,115 @@
+"""Tests para missingness_correlation."""
+
+from datascience.missingness_correlation import missingness_correlation
+
+
+def test_co_ocurrencia_fuerte_corr_uno_jaccard_uno():
+    # a y b faltan EXACTAMENTE en las mismas filas -> corr 1.0, jaccard 1.0.
+    mask = {
+        "a": [1, 0, 1, 0, 1, 0],
+        "b": [1, 0, 1, 0, 1, 0],
+    }
+    out = missingness_correlation(mask)
+    assert out["columns"] == ["a", "b"]
+    assert out["n_excluded"] == 0
+    # Diagonal 1.0, off-diagonal ~1.0.
+    assert out["matrix"][0][0] == 1.0
+    assert out["matrix"][1][1] == 1.0
+    assert abs(out["matrix"][0][1] - 1.0) < 1e-9
+    assert len(out["pairs"]) == 1
+    pair = out["pairs"][0]
+    assert {pair["a"], pair["b"]} == {"a", "b"}
+    assert abs(pair["corr"] - 1.0) < 1e-9
+    assert pair["co_missing"] == 3       # filas 0,2,4
+    assert pair["either_missing"] == 3   # mismas filas
+    assert abs(pair["jaccard"] - 1.0) < 1e-9
+
+
+def test_ausencias_disjuntas_corr_negativa_jaccard_cero():
+    # a y b nunca faltan en la misma fila -> co_missing 0, jaccard 0, corr <= 0.
+    mask = {
+        "a": [1, 1, 0, 0],
+        "b": [0, 0, 1, 1],
+    }
+    out = missingness_correlation(mask)
+    assert out["columns"] == ["a", "b"]
+    pair = out["pairs"][0]
+    assert pair["co_missing"] == 0
+    assert pair["either_missing"] == 4
+    assert pair["jaccard"] == 0.0
+    # Solapamiento nulo + ausencias complementarias -> correlacion negativa.
+    assert pair["corr"] < 0.0
+    assert abs(pair["corr"] - out["matrix"][0][1]) < 1e-12
+
+
+def test_columna_sin_varianza_se_excluye():
+    # c esta siempre presente (todo 0): no aporta ausencia -> no entra ni como
+    # excluida. d esta siempre ausente (todo 1): tiene nulos pero sin varianza
+    # -> excluida y n_excluded incrementa. a y b tienen varianza.
+    mask = {
+        "a": [1, 0, 1, 0],
+        "b": [1, 0, 0, 0],
+        "c": [0, 0, 0, 0],   # siempre presente
+        "d": [1, 1, 1, 1],   # siempre ausente, constante
+    }
+    out = missingness_correlation(mask)
+    assert out["columns"] == ["a", "b"]
+    assert "d" in out["excluded_cols"]
+    assert "c" not in out["excluded_cols"]
+    assert out["n_excluded"] == 1
+    # Matriz solo de las columnas con varianza.
+    assert len(out["matrix"]) == 2
+    assert len(out["matrix"][0]) == 2
+
+
+def test_menos_de_dos_columnas_con_varianza_vacio_pero_cuenta_excluidas():
+    # Solo una columna con varianza (a) + una constante-ausente (d).
+    mask = {
+        "a": [1, 0, 1, 0],
+        "d": [1, 1, 1, 1],
+    }
+    out = missingness_correlation(mask)
+    assert out["columns"] == []
+    assert out["matrix"] == []
+    assert out["pairs"] == []
+    assert out["n_excluded"] == 1
+    assert out["excluded_cols"] == ["d"]
+
+
+def test_mask_vacio_todo_vacio():
+    out = missingness_correlation({})
+    assert out == {
+        "columns": [],
+        "matrix": [],
+        "pairs": [],
+        "n_excluded": 0,
+        "excluded_cols": [],
+    }
+
+
+def test_top_k_limita_pares():
+    # 4 columnas con varianza -> 6 pares; top_k=2 deja 2.
+    mask = {
+        "a": [1, 0, 1, 0, 0],
+        "b": [1, 0, 0, 1, 0],
+        "c": [0, 1, 1, 0, 1],
+        "d": [1, 1, 0, 0, 1],
+    }
+    out = missingness_correlation(mask, top_k=2)
+    assert len(out["columns"]) == 4
+    assert len(out["pairs"]) == 2
+    # Ordenados por |corr| desc.
+    assert abs(out["pairs"][0]["corr"]) >= abs(out["pairs"][1]["corr"])
+
+
+def test_no_lanza_con_entradas_raras():
+    # Valores no-lista y no-dict no deben romper.
+    assert missingness_correlation(None)["columns"] == []
+    mask = {
+        "a": [1, 0, 1, 0],
+        "b": [1, 0, 1, 0],
+        "bad": "not a list",
+        "empty": [],
+    }
+    out = missingness_correlation(mask)
+    assert out["columns"] == ["a", "b"]

python/functions/datascience/missingness_overview.md

@@ -0,0 +1,99 @@
+---
+id: missingness_overview_py_datascience
+name: missingness_overview
+kind: function
+lang: py
+domain: datascience
+version: "1.0.0"
+purity: pure
+signature: "def missingness_overview(null_mask) -> dict"
+description: "Resumen de ausencias a nivel de dataset a partir de una máscara de nulos 0/1 por columna ({col: [1=falta, 0=presente]} alineada por fila). Calcula celdas y porcentaje de datos faltantes, cuántas columnas tienen algún nulo y cuántas filas son completas vs. incompletas. Estilo dict-no-throw del grupo eda: nunca lanza. Lectura defensiva — no-dict o dict vacío devuelve todo a 0; columnas no-lista se tratan como vacías; listas de longitud distinta se alinean a la longitud máxima rellenando la cola corta como presente (0); valores None/no-int cuentan como presente; sin ZeroDivisionError."
+tags: [eda, missing, missingness, nulls, profiling, datascience, pure]
+uses_functions: []
+uses_types: []
+returns: []
+returns_optional: false
+error_type: ""
+imports: []
+example: |
+  from datascience.missingness_overview import missingness_overview
+  mask = {
+      "a": [1, 0, 0, 0, 1],
+      "b": [1, 0, 1, 0, 0],
+      "c": [0, 0, 0, 0, 1],
+  }
+  missingness_overview(mask)
+  # n_missing_cells=5, missing_cell_pct≈33.33, complete_rows=2, incomplete_rows=3
+tested: true
+tests:
+  - "test_cooccurrence_three_cols_exact"
+  - "test_empty_dict_all_zero"
+  - "test_output_keys_contract"
+  - "test_not_a_dict_returns_zero"
+  - "test_no_nulls_all_complete"
+  - "test_none_values_treated_as_present"
+  - "test_unequal_lengths_pad_with_max"
+  - "test_columns_present_but_no_rows"
+  - "test_never_raises_on_garbage"
+test_file_path: "python/functions/datascience/missingness_overview_test.py"
+file_path: "python/functions/datascience/missingness_overview.py"
+params:
+  - name: null_mask
+    desc: "Dict {col_name: [int 0/1, ...]} con la máscara de nulos por columna, alineada por fila (1 = el valor falta, 0 = el valor está presente). Normalmente todas las listas tienen la misma longitud = nº de filas. Lectura defensiva: si no es dict o está vacío se devuelve todo a 0; columnas cuyo valor no es lista/tupla se tratan como vacías; listas de longitud distinta se alinean a la longitud máxima (las posiciones inexistentes de las columnas más cortas cuentan como presentes, 0); valores None o no enteros cuentan como presentes."
+output: "Dict con exactamente 9 claves, todas siempre presentes (la función nunca lanza): n_rows (longitud de fila = longitud máxima entre columnas, 0 si vacío), n_cols (nº de columnas), n_cols_with_null (columnas con >=1 falta), n_missing_cells (suma total de 1s), missing_cell_pct (0-100 = n_missing_cells / (n_rows*n_cols) * 100), complete_rows (filas sin ninguna falta), incomplete_rows (filas con >=1 falta), complete_pct (0-100), incomplete_pct (0-100). Los porcentajes son 0.0 cuando el denominador es 0 (sin ZeroDivisionError)."
+---
+
+## Ejemplo
+
+```python
+from datascience.missingness_overview import missingness_overview
+
+# Máscara de nulos por columna: 1 = falta, 0 = presente, alineada por fila.
+mask = {
+    "a": [1, 0, 0, 0, 1],
+    "b": [1, 0, 1, 0, 0],
+    "c": [0, 0, 0, 0, 1],
+}
+
+missingness_overview(mask)
+# {
+#   "n_rows": 5,
+#   "n_cols": 3,
+#   "n_cols_with_null": 3,      # a, b y c tienen al menos una falta
+#   "n_missing_cells": 5,       # 2 (a) + 2 (b) + 1 (c)
+#   "missing_cell_pct": 33.33,  # 5 / (5*3) * 100
+#   "complete_rows": 2,         # filas 1 y 3 sin ninguna falta
+#   "incomplete_rows": 3,       # filas 0 (a&b), 2 (b), 4 (a&c)
+#   "complete_pct": 40.0,       # 2 / 5 * 100
+#   "incomplete_pct": 60.0,     # 3 / 5 * 100
+# }
+
+missingness_overview({})
+# Todo a 0: {"n_rows": 0, "n_cols": 0, "n_cols_with_null": 0,
+#            "n_missing_cells": 0, "missing_cell_pct": 0.0,
+#            "complete_rows": 0, "incomplete_rows": 0,
+#            "complete_pct": 0.0, "incomplete_pct": 0.0}
+```
+
+## Cuando usarla
+
+Úsala al perfilar un dataset cuando ya tienes una máscara de nulos 0/1 por
+columna (p. ej. derivada del paso de carga/perfilado del EDA) y quieres la foto
+global de ausencias en una llamada: cuánta proporción de celdas falta, cuántas
+columnas están afectadas y, sobre todo, cuántas filas quedan completas vs.
+incompletas. Es el bloque resumen del capítulo de calidad/missingness de un EDA,
+y la base para decidir estrategias de imputación o de borrado de filas. Como es
+pura y dict-no-throw, puedes alimentarla con la máscara tal cual sin validarla
+antes: entradas malformadas degradan a ceros en vez de romper el pipeline.
+
+## Gotchas
+
+- **`n_rows` es la longitud máxima entre columnas.** Con listas de longitud
+  desigual, las posiciones que faltan en las columnas más cortas se cuentan como
+  presentes (`0`); no se descartan filas. En el caso normal (todas las listas de
+  igual longitud) `n_rows` es simplemente esa longitud.
+- **Solo el valor exacto `1` cuenta como falta.** `None`, `0`, cadenas y
+  cualquier otro valor se tratan como presentes. `True` (== 1) también cuenta
+  como falta por la igualdad.
+- **Porcentajes en escala 0-100**, no fracciones. División por cero protegida:
+  con `n_rows*n_cols == 0` los porcentajes salen `0.0`.

python/functions/datascience/missingness_overview.py

@@ -0,0 +1,116 @@
+"""Pure EDA helper: dataset-level missingness overview from a 0/1 null mask.
+
+Part of the `eda` capability group. Consumes a per-column null mask
+(``{col_name: [int 0/1, ...]}`` aligned by row, ``1`` = value is missing,
+``0`` = value is present) and derives dataset-wide missingness metrics: cell
+count and percentage of missing data, how many columns carry any null, and how
+many rows are complete vs. incomplete.
+
+Dict-no-throw style of the `eda` group: it NEVER raises. A non-dict, an empty
+dict, malformed columns, ragged lists or non-int cell values all degrade
+gracefully to the zero/contract output. Stdlib only.
+
+Ragged-length policy: columns are allowed to have different lengths. ``n_rows``
+is the **maximum** column length; positions that don't exist in a shorter
+column are treated as present (``0``). This keeps the ``n_rows * n_cols`` cell
+grid well defined without dropping rows.
+"""
+
+
+def _is_missing(value) -> int:
+    """Return ``1`` iff ``value`` denotes a missing cell, else ``0``.
+
+    Only an exact equality to ``1`` (covers ``int`` ``1`` and ``float`` ``1.0``)
+    counts as missing. ``None``, ``0``, strings and any other value are treated
+    as present. The comparison cannot raise for standard inputs.
+    """
+    try:
+        return 1 if value == 1 else 0
+    except Exception:
+        return 0
+
+
+def missingness_overview(null_mask) -> dict:
+    """Summarize dataset-level missingness from a 0/1 null mask.
+
+    Args:
+        null_mask: Dict ``{col_name: [int 0/1, ...]}`` where each list is aligned
+            by row (``1`` = missing, ``0`` = present). Lists are normally all the
+            same length (= number of rows). Defensive: a non-dict or empty dict
+            returns the all-zero contract; non-list columns are treated as empty;
+            ragged lists are aligned to the maximum length, padding the missing
+            tail of shorter columns as present (``0``); ``None`` / non-int cells
+            count as present.
+
+    Returns:
+        Dict with exactly these keys, all always present (the function never
+        raises): ``n_rows``, ``n_cols``, ``n_cols_with_null``,
+        ``n_missing_cells``, ``missing_cell_pct`` (0-100), ``complete_rows``,
+        ``incomplete_rows``, ``complete_pct`` (0-100), ``incomplete_pct``
+        (0-100). Percentages are ``0.0`` when the denominator is zero (no
+        ``ZeroDivisionError``).
+    """
+    zero = {
+        "n_rows": 0,
+        "n_cols": 0,
+        "n_cols_with_null": 0,
+        "n_missing_cells": 0,
+        "missing_cell_pct": 0.0,
+        "complete_rows": 0,
+        "incomplete_rows": 0,
+        "complete_pct": 0.0,
+        "incomplete_pct": 0.0,
+    }
+
+    if not isinstance(null_mask, dict) or not null_mask:
+        return dict(zero)
+
+    # Normalize every column to a list; non-list columns become empty.
+    cols = {}
+    for name, seq in null_mask.items():
+        cols[name] = seq if isinstance(seq, (list, tuple)) else []
+
+    n_cols = len(cols)
+    lengths = [len(seq) for seq in cols.values()]
+    n_rows = max(lengths) if lengths else 0
+
+    if n_rows == 0:
+        # Columns exist but carry no rows: everything zero except n_cols.
+        out = dict(zero)
+        out["n_cols"] = n_cols
+        return out
+
+    n_missing_cells = 0
+    n_cols_with_null = 0
+    row_has_missing = [False] * n_rows
+
+    for seq in cols.values():
+        col_len = len(seq)
+        col_has_null = False
+        for r in range(n_rows):
+            if r < col_len and _is_missing(seq[r]):
+                n_missing_cells += 1
+                row_has_missing[r] = True
+                col_has_null = True
+        if col_has_null:
+            n_cols_with_null += 1
+
+    incomplete_rows = sum(1 for flag in row_has_missing if flag)
+    complete_rows = n_rows - incomplete_rows
+
+    total_cells = n_rows * n_cols
+    missing_cell_pct = (n_missing_cells / total_cells * 100.0) if total_cells else 0.0
+    complete_pct = complete_rows / n_rows * 100.0
+    incomplete_pct = incomplete_rows / n_rows * 100.0
+
+    return {
+        "n_rows": n_rows,
+        "n_cols": n_cols,
+        "n_cols_with_null": n_cols_with_null,
+        "n_missing_cells": n_missing_cells,
+        "missing_cell_pct": missing_cell_pct,
+        "complete_rows": complete_rows,
+        "incomplete_rows": incomplete_rows,
+        "complete_pct": complete_pct,
+        "incomplete_pct": incomplete_pct,
+    }

python/functions/datascience/missingness_overview_test.py

@@ -0,0 +1,146 @@
+"""Tests para missingness_overview."""
+
+import sys
+import os
+
+import pytest
+
+sys.path.insert(0, os.path.dirname(__file__))
+
+from missingness_overview import missingness_overview
+
+
+# Output contract: every call returns exactly these 9 keys.
+EXPECTED_KEYS = {
+    "n_rows",
+    "n_cols",
+    "n_cols_with_null",
+    "n_missing_cells",
+    "missing_cell_pct",
+    "complete_rows",
+    "incomplete_rows",
+    "complete_pct",
+    "incomplete_pct",
+}
+
+
+def test_cooccurrence_three_cols_exact():
+    # 3 columns, 5 rows. Hand-computed expectations:
+    #   col a missing at rows 0, 4      -> 2
+    #   col b missing at rows 0, 2      -> 2
+    #   col c missing at row  4         -> 1
+    #   n_missing_cells = 5, total_cells = 5*3 = 15 -> 33.333...%
+    #   row 0 (a&b co-occur)  -> incomplete
+    #   row 1 (all present)   -> complete
+    #   row 2 (b only)        -> incomplete
+    #   row 3 (all present)   -> complete
+    #   row 4 (a&c co-occur)  -> incomplete
+    mask = {
+        "a": [1, 0, 0, 0, 1],
+        "b": [1, 0, 1, 0, 0],
+        "c": [0, 0, 0, 0, 1],
+    }
+    out = missingness_overview(mask)
+    assert out["n_rows"] == 5
+    assert out["n_cols"] == 3
+    assert out["n_cols_with_null"] == 3
+    assert out["n_missing_cells"] == 5
+    assert out["missing_cell_pct"] == pytest.approx(33.33333333, abs=1e-6)
+    assert out["complete_rows"] == 2
+    assert out["incomplete_rows"] == 3
+    assert out["complete_pct"] == pytest.approx(40.0)
+    assert out["incomplete_pct"] == pytest.approx(60.0)
+
+
+def test_empty_dict_all_zero():
+    out = missingness_overview({})
+    assert out == {
+        "n_rows": 0,
+        "n_cols": 0,
+        "n_cols_with_null": 0,
+        "n_missing_cells": 0,
+        "missing_cell_pct": 0.0,
+        "complete_rows": 0,
+        "incomplete_rows": 0,
+        "complete_pct": 0.0,
+        "incomplete_pct": 0.0,
+    }
+
+
+def test_output_keys_contract():
+    # The 9-key contract holds even for the garbage/zero path.
+    assert set(missingness_overview({}).keys()) == EXPECTED_KEYS
+    assert set(missingness_overview({"a": [1, 0]}).keys()) == EXPECTED_KEYS
+
+
+def test_not_a_dict_returns_zero():
+    for bad in (None, [1, 0, 1], 42, "nope", 3.14):
+        out = missingness_overview(bad)
+        assert out["n_rows"] == 0
+        assert out["n_cols"] == 0
+        assert out["n_missing_cells"] == 0
+        assert out["missing_cell_pct"] == 0.0
+
+
+def test_no_nulls_all_complete():
+    mask = {"a": [0, 0, 0], "b": [0, 0, 0]}
+    out = missingness_overview(mask)
+    assert out["n_rows"] == 3
+    assert out["n_cols"] == 2
+    assert out["n_cols_with_null"] == 0
+    assert out["n_missing_cells"] == 0
+    assert out["missing_cell_pct"] == 0.0
+    assert out["complete_rows"] == 3
+    assert out["incomplete_rows"] == 0
+    assert out["complete_pct"] == pytest.approx(100.0)
+    assert out["incomplete_pct"] == pytest.approx(0.0)
+
+
+def test_none_values_treated_as_present():
+    # None and other non-1 values count as present (0).
+    mask = {"a": [None, 1, None, "x", 0]}
+    out = missingness_overview(mask)
+    assert out["n_rows"] == 5
+    assert out["n_cols"] == 1
+    assert out["n_missing_cells"] == 1  # only the explicit 1 at row 1
+    assert out["n_cols_with_null"] == 1
+    assert out["complete_rows"] == 4
+    assert out["incomplete_rows"] == 1
+
+
+def test_unequal_lengths_pad_with_max():
+    # Ragged lists: n_rows = max length; shorter column padded as present.
+    #   a = [1, 1] -> missing at rows 0, 1
+    #   b = [0]    -> row 1 padded to present
+    #   n_rows = 2, n_cols = 2, total_cells = 4, n_missing_cells = 2 -> 50%
+    mask = {"a": [1, 1], "b": [0]}
+    out = missingness_overview(mask)
+    assert out["n_rows"] == 2
+    assert out["n_cols"] == 2
+    assert out["n_cols_with_null"] == 1
+    assert out["n_missing_cells"] == 2
+    assert out["missing_cell_pct"] == pytest.approx(50.0)
+    assert out["complete_rows"] == 0
+    assert out["incomplete_rows"] == 2
+    assert out["incomplete_pct"] == pytest.approx(100.0)
+
+
+def test_columns_present_but_no_rows():
+    # Columns exist but all empty -> zero metrics, n_cols preserved.
+    out = missingness_overview({"a": [], "b": []})
+    assert out["n_rows"] == 0
+    assert out["n_cols"] == 2
+    assert out["n_missing_cells"] == 0
+    assert out["missing_cell_pct"] == 0.0
+    assert out["complete_pct"] == 0.0
+
+
+def test_never_raises_on_garbage():
+    # Non-list column values, mixed junk -> must not raise.
+    mask = {"a": "not a list", "b": 123, "c": [1, 0, 1]}
+    out = missingness_overview(mask)
+    assert set(out.keys()) == EXPECTED_KEYS
+    assert out["n_rows"] == 3
+    assert out["n_cols"] == 3
+    assert out["n_missing_cells"] == 2  # only col c contributes
+    assert out["n_cols_with_null"] == 1

python/functions/datascience/missingness_rank_bar_figure.md

@@ -0,0 +1,93 @@
+---
+id: missingness_rank_bar_figure_py_datascience
+name: missingness_rank_bar_figure
+kind: function
+lang: py
+domain: datascience
+version: "1.0.0"
+purity: impure
+signature: "def missingness_rank_bar_figure(names, pcts, title=\"% de valores faltantes por columna\") -> \"matplotlib.figure.Figure\""
+description: "Construye una figura matplotlib de barras horizontales que ordena las columnas de un dataset por su porcentaje de valores faltantes (0-100), la mayor arriba, etiquetando cada barra con su NN.N% al final. Usa ax.barh, eje X fijo 0-100 y labels truncados a ~22 chars. Devuelve un matplotlib.figure.Figure listo para rasterizar por el renderer del informe EDA (capítulo de datos faltantes). Backend Agg sin pyplot global; defensivo ante listas vacías, longitudes desiguales o valores no numéricos (nunca lanza)."
+tags: [eda, missing, missingness, ranking, bar, barh, matplotlib, figure, visualization, datascience, impure]
+uses_functions: []
+uses_types: []
+returns: []
+returns_optional: false
+error_type: "error_go_core"
+imports: [matplotlib]
+example: |
+  from datascience.missingness_rank_bar_figure import missingness_rank_bar_figure
+  names = ["edad", "ingresos", "ciudad", "email"]
+  pcts = [12.5, 40.0, 3.2, 0.0]
+  fig = missingness_rank_bar_figure(names, pcts, title="% de valores faltantes por columna")
+tested: true
+tests:
+  - "test_returns_figure_with_axes"
+  - "test_sorted_descending_largest_on_top"
+  - "test_empty_lists_do_not_raise_and_returns_figure"
+  - "test_xlim_is_zero_to_hundred"
+  - "test_length_mismatch_and_non_numeric_are_handled"
+test_file_path: "python/functions/datascience/missingness_rank_bar_figure_test.py"
+file_path: "python/functions/datascience/missingness_rank_bar_figure.py"
+params:
+  - name: names
+    desc: "Lista de nombres de columna. Puede venir vacía (devuelve figura \"sin datos faltantes\"). Los items se convierten a str y se truncan a ~22 chars con elipsis para las etiquetas del eje Y; los originales no se mutan."
+  - name: pcts
+    desc: "Lista paralela a names con el % de nulos en [0,100]. Valores None, NaN o no numéricos se coercen a 0.0 y los negativos se recortan a 0. Si len(names) != len(pcts) se recorta al menor de ambos para no romper."
+  - name: title
+    desc: "Título de la figura. Se trunca a ~60 chars con elipsis si es muy largo. Default \"% de valores faltantes por columna\"."
+output: "Un matplotlib.figure.Figure (figsize 6.4 x alto adaptativo según nº de barras, dpi 150) con un Axes de barras horizontales (ax.barh) ordenadas por % descendente, la mayor arriba. Eje X fijado a [0,100] con label \"% faltante\", etiquetas del eje Y truncadas a ~22 chars, y cada barra anotada con su NN.N% al final. Si names o pcts vienen vacíos devuelve una Figure con texto centrado \"sin datos faltantes\"; cualquier error inesperado se captura y devuelve una Figure con el mensaje de error (nunca lanza). El caller rasteriza/cierra la figura; la función no la muestra ni la guarda."
+---
+
+## Ejemplo
+
+```python
+from datascience.missingness_rank_bar_figure import missingness_rank_bar_figure
+
+# % de nulos por columna (p. ej. (df.isnull().mean() * 100).
+names = ["edad", "ingresos", "ciudad", "email"]
+pcts = [12.5, 40.0, 3.2, 0.0]
+
+fig = missingness_rank_bar_figure(
+    names,
+    pcts,
+    title="% de valores faltantes por columna",
+)
+
+# ingresos (40.0%) queda arriba; email (0.0%) abajo.
+# El renderer del informe lo rasteriza; aquí solo persistimos para inspección.
+fig.savefig("/tmp/missingness_rank.png")
+```
+
+## Cuando usarla
+
+Úsala al abrir el capítulo de datos faltantes de un informe EDA para responder
+"¿qué columnas están más incompletas?" de un vistazo. Pásale los nombres de
+columna y el % de nulos de cada una (`(df.isnull().mean() * 100).round(1)`); la
+función se encarga de ordenar de mayor a menor y poner la peor arriba. Es la
+pareja "magnitud" del heatmap de co-ocurrencia: las barras dicen *cuánto* falta
+en cada columna, el heatmap dice *si esas ausencias están relacionadas* entre
+columnas.
+
+## Gotchas
+
+- **Impura por matplotlib.** Toca la maquinaria de render. Usa el backend `Agg`
+  y la API orientada a objetos `Figure`/`add_subplot` — NUNCA `pyplot.*` aquí,
+  para no tocar el estado global ni filtrar figuras entre llamadas. `pyplot` NO
+  es thread-safe; esta función evita ese riesgo construyendo el `Figure`
+  directamente, así que es segura de llamar en bucle desde el renderer.
+- **El caller cierra la figura.** Devuelve el `Figure` pero no lo muestra ni lo
+  guarda. Quien la consume debe rasterizarla y luego liberarla
+  (`matplotlib.pyplot.close(fig)`) para no acumular memoria en lotes grandes.
+- **Espera porcentajes 0-100, no fracciones 0-1.** El eje X está fijado a
+  `[0, 100]`. Si pasas fracciones (`0.4` en vez de `40.0`) las barras saldrán
+  pegadas al origen. Multiplica por 100 antes de llamar.
+- **Alto adaptativo.** La altura de la figura crece con el número de barras
+  (hasta un tope) para que reports con muchas columnas sigan legibles; aun así,
+  conviene filtrar a las columnas con algún nulo antes de llamar para no listar
+  decenas de barras a 0%.
+- **Defensiva, nunca lanza.** Listas vacías, longitudes desiguales, valores
+  `None`/`NaN`/no numéricos o cualquier error inesperado se manejan sin propagar:
+  en el peor caso devuelve una `Figure` con "sin datos faltantes" o con el texto
+  del error. No envuelvas la llamada en try/except por miedo a un raise — no lo
+  hay.

python/functions/datascience/missingness_rank_bar_figure.py

@@ -0,0 +1,150 @@
+"""Impure EDA helper: ranked bar figure of missing-value share (`eda` group).
+
+Builds a horizontal bar chart ranking the columns of a dataset by their
+percentage of missing values (0-100), largest at the top, each bar labelled with
+its ``NN.N%`` at the end. Returns a ready-to-rasterize
+``matplotlib.figure.Figure``; it never shows nor saves it.
+
+Impure because it touches matplotlib's rendering machinery. It uses the headless
+Agg backend and the object-oriented ``Figure`` API (no ``pyplot``) so it leaks no
+global state and is safe to call repeatedly from a report renderer.
+"""
+
+import matplotlib
+
+matplotlib.use("Agg")
+
+from matplotlib.figure import Figure  # noqa: E402
+
+# Muted gray for secondary text (no-data / fallback messages).
+_MUTED_TEXT = "#5f6b7a"
+# Soft red for the error fallback message.
+_ERROR_TEXT = "#b00020"
+# Bar fill — a calm blue that reads well on white at report size.
+_BAR_COLOR = "#4C72B0"
+
+
+def _truncate(text, width: int = 22) -> str:
+    """Truncate ``text`` to ``width`` chars, appending an ellipsis if cut."""
+    s = "" if text is None else str(text)
+    if len(s) <= width:
+        return s
+    if width <= 1:
+        return s[:width]
+    return s[: width - 1] + "…"
+
+
+def _message_figure(message: str, color: str = _MUTED_TEXT) -> "Figure":
+    """Return a fallback ``Figure`` carrying a single centered message."""
+    fig = Figure(figsize=(6.4, 4.0), dpi=150)
+    ax = fig.add_subplot(111)
+    ax.axis("off")
+    ax.text(
+        0.5,
+        0.5,
+        message,
+        ha="center",
+        va="center",
+        fontsize=12,
+        color=color,
+        wrap=True,
+        transform=ax.transAxes,
+    )
+    fig.tight_layout()
+    return fig
+
+
+def missingness_rank_bar_figure(
+    names,
+    pcts,
+    title: str = "% de valores faltantes por columna",
+) -> "matplotlib.figure.Figure":
+    """Build a horizontal ranked bar figure of missing-value share per column.
+
+    Pairs each column name with its missing percentage, sorts by percentage
+    descending and draws horizontal bars with the largest at the top. The X axis
+    is pinned to ``[0, 100]`` so bars are comparable across reports, each bar is
+    annotated with its ``NN.N%`` at the end, and the Y tick labels are truncated
+    to ~22 chars.
+
+    The function is fully defensive: empty/mismatched/non-numeric input never
+    raises. When there is nothing valid to draw it returns a ``Figure`` carrying
+    a centered "sin datos faltantes" message, and any unexpected error is caught
+    and turned into a fallback ``Figure`` carrying the error text.
+
+    Args:
+        names: List of column names. May be empty. Items are stringified and
+            truncated for display; the originals are not mutated.
+        pcts: List parallel to ``names`` of missing-value percentages in
+            ``[0, 100]``. Non-numeric/``None`` values are coerced to ``0.0`` and
+            negatives are clamped to ``0``. The list is truncated to
+            ``min(len(names), len(pcts))`` so a length mismatch never crashes.
+        title: Figure title. Default "% de valores faltantes por columna".
+
+    Returns:
+        A ``matplotlib.figure.Figure`` with a single horizontal-bar Axes. The
+        caller is responsible for rasterizing/closing it.
+    """
+    try:
+        if (
+            not isinstance(names, (list, tuple))
+            or not isinstance(pcts, (list, tuple))
+            or len(names) == 0
+            or len(pcts) == 0
+        ):
+            return _message_figure("sin datos faltantes")
+
+        # --- Pair names with coerced percentages, tolerating length mismatch.
+        pairs = []
+        for name, pct in zip(names, pcts):
+            try:
+                val = float(pct)
+            except (TypeError, ValueError):
+                val = 0.0
+            if val != val:  # NaN guard.
+                val = 0.0
+            val = max(0.0, val)
+            pairs.append((name, val))
+
+        if not pairs:
+            return _message_figure("sin datos faltantes")
+
+        # Sort by percentage descending; barh draws bottom-up, so the largest
+        # ends at the top when we reverse the order before plotting.
+        pairs.sort(key=lambda p: p[1], reverse=True)
+        ordered = list(reversed(pairs))  # smallest first -> largest on top.
+
+        labels = [_truncate(name, 22) for name, _ in ordered]
+        values = [val for _, val in ordered]
+        y_pos = range(len(ordered))
+
+        # Height scales with the number of bars so dense reports stay readable.
+        height = max(2.4, min(0.4 * len(ordered) + 1.2, 14.0))
+        fig = Figure(figsize=(6.4, height), dpi=150)
+        ax = fig.add_subplot(111)
+
+        ax.barh(list(y_pos), values, color=_BAR_COLOR, edgecolor="white")
+        ax.set_yticks(list(y_pos))
+        ax.set_yticklabels(labels, fontsize=8)
+        ax.set_xlim(0, 100)
+        ax.set_xlabel("% faltante", fontsize=9)
+
+        # Annotate each bar with its percentage at the end of the bar.
+        for y, val in zip(y_pos, values):
+            ax.text(
+                min(val + 1.5, 99.0),
+                y,
+                f"{val:.1f}%",
+                va="center",
+                ha="left" if val < 90 else "right",
+                fontsize=7,
+                color="#202020",
+            )
+
+        if title:
+            ax.set_title(_truncate(title, 60), fontsize=12, loc="left", pad=10)
+
+        fig.tight_layout()
+        return fig
+    except Exception as exc:  # noqa: BLE001 — never raise from a figure builder.
+        return _message_figure(f"error al dibujar barras: {exc}", color=_ERROR_TEXT)

python/functions/datascience/missingness_rank_bar_figure_test.py

@@ -0,0 +1,64 @@
+"""Tests para missingness_rank_bar_figure (barras de % faltante, grupo eda).
+
+Usa el backend Agg sin pyplot; no muestra ni guarda figuras. Cada test cierra
+explícitamente la Figure construida (matplotlib.pyplot.close) para no acumular
+estado entre tests.
+"""
+
+import matplotlib
+
+matplotlib.use("Agg")
+
+import matplotlib.pyplot as plt  # noqa: E402
+from matplotlib.figure import Figure  # noqa: E402
+
+from missingness_rank_bar_figure import missingness_rank_bar_figure
+
+
+def test_returns_figure_with_axes():
+    names = ["edad", "ingresos", "ciudad"]
+    pcts = [12.5, 40.0, 3.2]
+    fig = missingness_rank_bar_figure(names, pcts, title="faltantes")
+    assert isinstance(fig, Figure)
+    assert len(fig.axes) >= 1
+    plt.close(fig)
+
+
+def test_sorted_descending_largest_on_top():
+    names = ["a", "b", "c"]
+    pcts = [10.0, 50.0, 25.0]
+    fig = missingness_rank_bar_figure(names, pcts)
+    ax = fig.axes[0]
+    # barh dibuja de abajo arriba; la mayor (50, "b") debe quedar arriba (mayor y).
+    bars = ax.patches
+    # El último parche (mayor índice y) corresponde a la barra superior.
+    widths = [b.get_width() for b in bars]
+    assert max(widths) == 50.0
+    # La barra con la mayor anchura es la de mayor coordenada y (arriba).
+    top_bar = max(bars, key=lambda b: b.get_y())
+    assert top_bar.get_width() == 50.0
+    plt.close(fig)
+
+
+def test_empty_lists_do_not_raise_and_returns_figure():
+    fig = missingness_rank_bar_figure([], [], title="vacía")
+    assert isinstance(fig, Figure)
+    assert len(fig.axes) >= 1
+    plt.close(fig)
+
+
+def test_xlim_is_zero_to_hundred():
+    fig = missingness_rank_bar_figure(["a"], [42.0])
+    ax = fig.axes[0]
+    assert ax.get_xlim() == (0.0, 100.0)
+    plt.close(fig)
+
+
+def test_length_mismatch_and_non_numeric_are_handled():
+    # Más names que pcts + un pct None -> zip recorta y None se coacciona a 0.
+    names = ["a", "b", "c"]
+    pcts = [None, 30.0]
+    fig = missingness_rank_bar_figure(names, pcts)
+    assert isinstance(fig, Figure)
+    assert len(fig.axes) >= 1
+    plt.close(fig)

python/functions/datascience/missingness_row_patterns.md

@@ -0,0 +1,65 @@
+---
+name: missingness_row_patterns
+kind: function
+lang: py
+domain: datascience
+version: "1.0.0"
+purity: pure
+signature: "def missingness_row_patterns(null_mask, top_n=10) -> dict"
+description: "Agrupa las filas de un dataset por su patron de ausencias (estilo matriz de missingno): para cada fila, el patron es la tupla ORDENADA de columnas que faltan en esa fila (las que tienen 1 en el null_mask). Cuenta la frecuencia de cada patron distinto, incluido el patron vacio (fila completa). Devuelve el top_n por frecuencia con su pct sobre el total. Pura, lectura defensiva, NUNCA lanza; {} -> n_rows 0."
+tags: [eda, missingness, missingno, patterns, profiling, datascience, data-quality]
+params:
+  - name: null_mask
+    desc: "Dict {col: [0/1, ...]} alineado por fila, donde 1 = la celda falta en esa fila y 0 = presente. Todas las columnas deberian tener la misma longitud (una entrada por fila); si difieren, n_rows es la lista mas larga y las celdas fuera de rango cuentan como presentes. Las claves se ordenan por str(col) para canonizar el patron. {} (o no-dict) -> n_rows 0."
+  - name: top_n
+    desc: "Maximo de patrones devueltos en `patterns`, rankeados por n_rows desc (desempate: menos columnas primero, luego nombres de columna). El recuento total de patrones distintos siempre se reporta en `n_patterns`, no se trunca. Default 10. Valores negativos -> 0; no-int -> 10."
+output: "Dict {n_rows: int (filas totales), n_patterns: int (patrones distintos, incluye el patron vacio = fila completa), complete_rows: int (filas con patron vacio, nada falta), patterns: lista del top_n ordenada por n_rows desc con [{missing_cols: [col,...] (vacio = fila completa), n_rows: int, pct: float 0-100 sobre n_rows total, redondeado a 2 decimales}]}. Para {} devuelve n_rows 0 y patterns []. NUNCA lanza."
+uses_functions: []
+uses_types: []
+returns: []
+returns_optional: false
+error_type: ""
+imports: []
+tested: true
+tests: ["test_patron_dominante_completas_singleton", "test_mask_vacio", "test_top_n_trunca_pero_cuenta_todos"]
+test_file_path: "python/functions/datascience/missingness_row_patterns_test.py"
+file_path: "python/functions/datascience/missingness_row_patterns.py"
+---
+
+## Ejemplo
+
+```python
+import sys, os
+sys.path.insert(0, os.path.join("python", "functions"))
+from datascience.missingness_row_patterns import missingness_row_patterns
+
+# null_mask alineado por fila: 1 = la celda falta en esa fila.
+null_mask = {
+    "A": [1, 1, 1, 1, 0, 0, 0, 0, 0, 0],
+    "B": [1, 1, 1, 1, 0, 0, 0, 0, 0, 0],
+    "C": [0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
+}
+out = missingness_row_patterns(null_mask, top_n=10)
+print(out["n_rows"], out["n_patterns"], out["complete_rows"])  # 10 3 5
+for p in out["patterns"]:
+    label = p["missing_cols"] or "(fila completa)"
+    print(label, p["n_rows"], p["pct"])
+# (fila completa) 5 50.0
+# ['A', 'B'] 4 40.0
+# ['C'] 1 10.0
+```
+
+## Cuando usarla
+
+- Usala en el capitulo de calidad/ausencias de `AutomaticEDA` para mostrar la "matriz de patrones de missingno": en vez de pintar celda a celda, resume que combinaciones de columnas se quedan en blanco juntas y con que frecuencia.
+- Cuando ya tengas el null_mask por columna (1=falta) y quieras detectar co-ausencia estructural ("A y B siempre faltan juntas") antes de decidir una imputacion o un drop conjunto de columnas.
+- Cuando necesites una tabla compacta "patron -> nº filas -> pct" para un report o un grafico de barras de los patrones de ausencia mas comunes, separando ademas cuantas filas estan completas (`complete_rows`).
+
+## Gotchas
+
+- Funcion pura, sin I/O y determinista. Lectura defensiva: `{}` o un no-dict devuelven `n_rows` 0 con `patterns` []. NUNCA lanza.
+- El patron vacio (fila completa, `missing_cols=[]`) SI cuenta como patron: aparece en `n_patterns` y puede aparecer en `patterns`. El consumidor lo etiqueta como "(fila completa)".
+- `pct` es sobre `n_rows` total (0-100), redondeado a 2 decimales. La suma de los `pct` de TODOS los patrones es 100; si `top_n` trunca, los `pct` mostrados sumaran menos.
+- Las columnas se ordenan por `str(col)` para canonizar cada patron, asi `{A,B}` y `{B,A}` colapsan al mismo patron `["A", "B"]`.
+- Una celda cuenta como ausente solo si vale 1 (`int(cell) == 1`); 0, None y valores no numericos se tratan como presentes.
+- Si las listas de columnas tienen longitudes distintas, `n_rows` es la mas larga y las posiciones fuera de rango de una columna corta cuentan como presentes (0).

python/functions/datascience/missingness_row_patterns.py

@@ -0,0 +1,107 @@
+"""missingness_row_patterns — distinct per-row missingness patterns (missingno matrix style).
+
+Pure function: no I/O, deterministic, NEVER raises. Given a per-column null mask
+aligned by row ({col: [0/1, ...]}, 1 = missing), it groups rows by their missing
+"pattern" — the sorted tuple of column names that are missing in that row — and
+counts how often each distinct pattern occurs.
+
+This mirrors the missingno matrix idea: instead of plotting per-cell nullity, it
+collapses each row to the SET of columns it lacks, surfacing co-missing structure
+(e.g. "A and B always go missing together"). The empty pattern (a fully complete
+row) is a first-class pattern and may appear in the result with missing_cols=[];
+the caller labels it "(fila completa)".
+"""
+
+
+def _is_missing(cell) -> bool:
+    """A cell counts as missing when it equals 1 (truthy 0/1 mask).
+
+    None / 0 / non-numeric are treated as present. Defensive: never raises.
+    """
+    try:
+        return int(cell) == 1
+    except (TypeError, ValueError):
+        return bool(cell)
+
+
+def missingness_row_patterns(null_mask, top_n=10) -> dict:
+    """Count distinct per-row missingness patterns from a column null mask.
+
+    For each row, its pattern is the sorted tuple of column names missing in that
+    row (the columns whose value is 1). The frequency of each distinct pattern is
+    counted, including the empty pattern (a complete row with nothing missing).
+
+    Args:
+        null_mask: Dict {col: [0/1, ...]} aligned by row, where 1 means the cell
+            is missing in that row. Read defensively; columns with differing
+            lengths are tolerated (n_rows is the longest list; out-of-range cells
+            count as present). Empty dict -> n_rows 0.
+        top_n: Maximum number of patterns returned in `patterns`, ranked by
+            n_rows desc (tiebreak: fewer columns first, then column names). The
+            full count of distinct patterns is always reported in `n_patterns`.
+
+    Returns:
+        Dict:
+        {
+          "n_rows": int,            # total rows
+          "n_patterns": int,        # distinct patterns (incl. the empty pattern)
+          "complete_rows": int,     # rows with the empty pattern (nothing missing)
+          "patterns": [             # top_n patterns, n_rows desc
+             {"missing_cols": [col, ...], "n_rows": int, "pct": float}  # [] = complete row
+          ],
+        }
+        For {} (or a non-dict) returns n_rows 0 and patterns []. NEVER raises.
+    """
+    empty = {"n_rows": 0, "n_patterns": 0, "complete_rows": 0, "patterns": []}
+    if not isinstance(null_mask, dict) or not null_mask:
+        return empty
+
+    # Stable, canonical column order so each row's pattern tuple is sorted.
+    items = sorted(null_mask.items(), key=lambda kv: str(kv[0]))
+    names = [str(k) for k, _ in items]
+    lists = [v if isinstance(v, (list, tuple)) else [] for _, v in items]
+
+    n_rows = max((len(lst) for lst in lists), default=0)
+    if n_rows == 0:
+        return empty
+
+    # Defensive parsing of top_n.
+    try:
+        limit = int(top_n)
+    except (TypeError, ValueError):
+        limit = 10
+    if limit < 0:
+        limit = 0
+
+    counts: dict = {}
+    n_cols = len(names)
+    for r in range(n_rows):
+        # names is sorted, so iterating in order yields an already-sorted tuple.
+        pattern = tuple(
+            names[c]
+            for c in range(n_cols)
+            if r < len(lists[c]) and _is_missing(lists[c][r])
+        )
+        counts[pattern] = counts.get(pattern, 0) + 1
+
+    complete_rows = counts.get((), 0)
+    n_patterns = len(counts)
+
+    # Rank: n_rows desc, then fewer columns first, then column names (deterministic).
+    ordered = sorted(counts.items(), key=lambda kv: (-kv[1], len(kv[0]), kv[0]))
+
+    patterns = [
+        {
+            "missing_cols": list(pat),
+            "n_rows": cnt,
+            "pct": round(100.0 * cnt / n_rows, 2),
+        }
+        for pat, cnt in ordered[:limit]
+    ]
+
+    return {
+        "n_rows": n_rows,
+        "n_patterns": n_patterns,
+        "complete_rows": complete_rows,
+        "patterns": patterns,
+    }

python/functions/datascience/missingness_row_patterns_test.py

@@ -0,0 +1,87 @@
+"""Tests para missingness_row_patterns."""
+
+import os
+import sys
+
+sys.path.insert(0, os.path.dirname(__file__))
+
+from missingness_row_patterns import missingness_row_patterns
+
+_EXPECTED_KEYS = {"n_rows", "n_patterns", "complete_rows", "patterns"}
+
+
+def test_patron_dominante_completas_singleton():
+    """Golden: {A,B} co-faltan en 4 filas + 5 filas completas + 1 singleton {C}."""
+    # 10 filas. A y B faltan juntas en las filas 0-3; filas 4-8 completas;
+    # la fila 9 solo le falta C.
+    null_mask = {
+        "A": [1, 1, 1, 1, 0, 0, 0, 0, 0, 0],
+        "B": [1, 1, 1, 1, 0, 0, 0, 0, 0, 0],
+        "C": [0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
+    }
+    out = missingness_row_patterns(null_mask)
+
+    assert set(out.keys()) == _EXPECTED_KEYS
+    assert out["n_rows"] == 10
+    # 3 patrones distintos: (A,B), () y (C,).
+    assert out["n_patterns"] == 3
+    # 5 filas completas (filas 4-8).
+    assert out["complete_rows"] == 5
+
+    # Orden: n_rows desc; desempate menos columnas primero.
+    # () tiene 5 filas, (A,B) 4, (C,) 1.
+    pats = out["patterns"]
+    assert len(pats) == 3
+
+    assert pats[0]["missing_cols"] == []
+    assert pats[0]["n_rows"] == 5
+    assert pats[0]["pct"] == 50.0
+
+    assert pats[1]["missing_cols"] == ["A", "B"]
+    assert pats[1]["n_rows"] == 4
+    assert pats[1]["pct"] == 40.0
+
+    assert pats[2]["missing_cols"] == ["C"]
+    assert pats[2]["n_rows"] == 1
+    assert pats[2]["pct"] == 10.0
+
+    # Tipos de salida.
+    assert isinstance(out["n_rows"], int)
+    assert isinstance(pats[0]["pct"], float)
+
+
+def test_mask_vacio():
+    """{} -> n_rows 0, sin patrones, nunca lanza."""
+    out = missingness_row_patterns({})
+    assert out == {
+        "n_rows": 0,
+        "n_patterns": 0,
+        "complete_rows": 0,
+        "patterns": [],
+    }
+    # No dict / None tambien degradan a vacio sin lanzar.
+    assert missingness_row_patterns(None)["n_rows"] == 0
+    # Columnas presentes pero listas vacias -> n_rows 0.
+    assert missingness_row_patterns({"A": [], "B": []})["patterns"] == []
+
+
+def test_top_n_trunca_pero_cuenta_todos():
+    """top_n limita `patterns`, pero n_patterns reporta TODOS los distintos."""
+    null_mask = {
+        "A": [0, 1, 1, 0, 1],
+        "B": [0, 0, 0, 1, 1],
+        "C": [0, 0, 0, 0, 1],
+    }
+    # Filas: ()  (A,)  (A,)  (B,)  (A,B,C)
+    out = missingness_row_patterns(null_mask, top_n=2)
+
+    assert out["n_rows"] == 5
+    assert out["n_patterns"] == 4          # (), (A,), (B,), (A,B,C)
+    assert out["complete_rows"] == 1
+    # Solo 2 patrones devueltos pese a haber 4.
+    assert len(out["patterns"]) == 2
+    # (A,) domina con 2 filas; desempate del 2o entre los de 1 fila -> () (0 cols).
+    assert out["patterns"][0]["missing_cols"] == ["A"]
+    assert out["patterns"][0]["n_rows"] == 2
+    assert out["patterns"][1]["missing_cols"] == []
+    assert out["patterns"][1]["n_rows"] == 1

python/functions/datascience/render_automatic_eda_markdown.md

@@ -0,0 +1,89 @@
+---
+name: render_automatic_eda_markdown
+kind: function
+lang: py
+domain: datascience
+version: "1.0.0"
+purity: impure
+signature: "def render_automatic_eda_markdown(chapters_or_profile, out_path: str, meta: dict = None) -> dict"
+description: "Renderiza un documento AutomaticEDA por CAPÍTULOS (modelo de bloques independiente del formato) en un único MARKDOWN autocontenido pensado para PEGAR A UN LLM. Acepta una lista de capítulos del modelo o directamente un TableProfile del grupo eda (construye los capítulos canónicos con build_document). Prioriza TEXTO + DATOS sobre lo visual: las tablas se vuelcan como tablas markdown con TODAS las filas (sin paginar — no hay páginas que cortar), una figura matplotlib se reduce a su caption más la tabla de datos subyacente (Desde/Hasta/Frecuencia de las barras del histograma) porque un LLM no ve la imagen, y los marcadores de glosario se eliminan conservando el **negrita**. Lleva cabecera (# título), bloque de metadatos en blockquote e índice numerado con anclas GitHub. Espejo de render_automatic_eda_pdf/render_automatic_eda_pptx pero SIN manifest (KISS, el markdown es un único artefacto de texto). dict-no-throw: nunca lanza, devuelve {path, n_chars, chapters, note}; en error fatal path es None y note explica la causa. Flag opcional meta['embed_figures'] exporta PNGs junto al .md (off por defecto)."
+tags: [eda, markdown, render, report, llm, automatic-eda, chapters, versioned, no-cut, text, datascience, python]
+uses_functions: []
+uses_types: []
+returns: []
+returns_optional: false
+error_type: "error_go_core"
+imports: [os, re, matplotlib, "datascience.automatic_eda"]
+params:
+  - name: chapters_or_profile
+    desc: "una lista de capítulos del modelo AutomaticEDA (dataclasses Chapter o dicts {id,title,version,blocks}) O un TableProfile dict del grupo eda. Si es un TableProfile, los capítulos canónicos se construyen con build_document(profile, meta['ctx']). Bloques soportados: heading, markdown, kv_table, data_table, figure, image, caption, note, group, glossary_entry. Lectura defensiva: lo no reconocido se degrada a Note, nunca lanza."
+  - name: out_path
+    desc: "ruta del archivo .md de salida. Los directorios padre se crean si faltan. Directorio no escribible → {path:None, note:<causa>} sin lanzar."
+  - name: meta
+    desc: "dict opcional. Claves: title (título del documento), ctx (dict con dataset_name→Dataset, source_origin→Fuente, storage→Almacenamiento, n_rows/n_cols→Dimensiones; también lo consumen los builders de capítulo cuando se da un profile), generated_at (timestamp; si falta se genera ISO UTC), embed_figures (True para exportar PNGs <basename>_figN.png junto al .md; por defecto False y el markdown queda autocontenido)."
+output: "dict (nunca lanza): {path: str|None, n_chars: int, chapters: list[{id,version}], note: str}. En error fatal (p.ej. directorio no escribible) path es None y note explica la causa. Un documento sin capítulos aplicables produce un markdown mínimo válido con 'documento vacío' y chapters=[]."
+tested: true
+tests: ["test_golden_bloques_sinteticos_serializa_todo_a_markdown", "test_edge_documento_vacio_no_revienta", "test_profile_path_construye_capitulos_y_escribe"]
+test_file_path: "python/functions/datascience/render_automatic_eda_markdown_test.py"
+file_path: "python/functions/datascience/render_automatic_eda_markdown.py"
+---
+
+## Ejemplo
+
+```python
+from datascience import render_automatic_eda_markdown
+
+# Desde un TableProfile del grupo eda (mismo modelo que los renderers PDF/PPTX).
+profile = {
+    "table": "ventas", "source": "/data/ventas.csv",
+    "n_rows": 1000, "n_cols": 2, "quality_score": 92.5,
+    "columns": [
+        {"name": "precio", "inferred_type": "numeric", "null_pct": 0.01,
+         "numeric": {"mean": 42.5, "median": 40.0, "min": 1.0, "max": 100.0,
+                     "std": 12.3}},
+        {"name": "categoria", "inferred_type": "categorical", "null_pct": 0.0,
+         "categorical": {"top": [{"value": "neumaticos", "count": 500}]}},
+    ],
+}
+res = render_automatic_eda_markdown(
+    profile, "reports/ventas_aeda.md",
+    {"title": "EDA — ventas",
+     "ctx": {"dataset_name": "Ventas", "source_origin": "ERP export",
+             "n_rows": 1000, "n_cols": 2}})
+print(res["path"], res["n_chars"], res["chapters"])
+# -> reports/ventas_aeda.md 4123 [{'id':'portada','version':'1.0.0'}, ...]
+```
+
+## Cuando usarla
+
+Cuando quieras **pegar el EDA a un LLM** (ChatGPT, Claude, ...) o tenerlo en texto
+plano versionable: mismo documento por capítulos que el PDF/PPTX, pero serializado a
+Markdown sin binarios. Úsala como tercera salida junto a `render_automatic_eda_pdf`
+(móvil) y `render_automatic_eda_pptx` (compartir) desde el MISMO modelo de capítulos.
+A diferencia de esas dos, no hay páginas ni slides: todas las filas de cada tabla se
+vuelcan (nada se corta) y cada figura se reduce a su caption + la tabla de datos
+subyacente, que es lo que un LLM puede leer. Para añadir capítulos al documento, ver
+`docs/capabilities/automatic_eda.md`.
+
+## Gotchas
+
+- **Impura**: escribe el `.md` en `out_path` (crea los directorios padre). Con
+  `meta['embed_figures']=True` además exporta un PNG `<basename>_figN.png` por figura
+  junto al `.md`; por defecto NO exporta nada y el markdown queda autocontenido.
+- **Nunca lanza** (dict-no-throw): un bloque que falle se degrada a una nota y se anota
+  en `note`; el documento se escribe igual. Un profile/lista vacíos producen un markdown
+  mínimo válido con `*(documento vacío …)*` y `chapters=[]`.
+- **Figuras = datos, no imagen**: un bloque `figure` se serializa como `*Figura: caption*`
+  más, si la figura matplotlib trae barras (histograma / barras), una tabla
+  `| Desde | Hasta | Frecuencia |` extraída de los `Rectangle` patches (máx 100 filas;
+  el resto se trunca con `*… (N filas más)*`). Si no hay barras o algo falla, solo sale
+  el caption. La figura se cierra (`plt.close`) tras leerla.
+- **Glosario vs negrita**: se eliminan SOLO los marcadores de glosario
+  `[[term:key]]visible[[/term]]` (queda `visible`); el `**negrita**` markdown SE
+  CONSERVA (es válido). No se usa `strip_inline_md` aquí porque ese también quita el bold.
+- **Anclas del índice**: el `## Índice` enlaza cada capítulo con un ancla estilo GitHub
+  del encabezado `## N. Título` (minúsculas, espacios→`-`, sin signos). Si dos capítulos
+  comparten título exacto sus anclas colisionan (caso raro; los capítulos canónicos tienen
+  títulos únicos).
+- **Tablas**: las celdas escapan `|` (→ `\|`) y pliegan saltos de línea a `<br>` para no
+  romper la columna. No hay reparto por ancho — un LLM no lo necesita.

python/functions/datascience/render_automatic_eda_markdown.py

@@ -0,0 +1,55 @@
+"""render_automatic_eda_markdown — chapter-based EDA report as one Markdown file.
+
+Public ``eda``-group entry point that serializes an AutomaticEDA document (a list
+of chapters, or an ``eda`` TableProfile from which the canonical chapters are
+built) into a single self-contained Markdown file optimised to be **pasted into
+an LLM**: plain text, Markdown tables (every row dumped — there are no pages to
+cut), figures reduced to caption + underlying data, no binaries. It mirrors
+``render_automatic_eda_pdf`` / ``render_automatic_eda_pptx`` but for text output;
+unlike those it writes no manifest (KISS — Markdown is a single text artefact).
+
+dict-no-throw: never raises. Returns ``{path, n_chars, chapters, note}``; on a
+fatal error ``path`` is None and ``note`` explains why.
+"""
+
+from __future__ import annotations
+
+from datascience.automatic_eda import build_document, render_md
+from datascience.automatic_eda.model import as_chapter, as_chapters
+
+
+def _coerce_chapters(chapters_or_profile, meta: dict) -> list:
+    """Accept chapters OR an eda profile and return a list of Chapter."""
+    arg = chapters_or_profile
+    if isinstance(arg, (list, tuple)):
+        return as_chapters(list(arg))
+    if isinstance(arg, dict):
+        if "blocks" in arg and "columns" not in arg:
+            ch = as_chapter(arg)
+            return [ch] if ch is not None else []
+        return build_document(arg, (meta or {}).get("ctx"))
+    return []
+
+
+def render_automatic_eda_markdown(chapters_or_profile, out_path: str,
+                                  meta: dict = None) -> dict:
+    """Render an AutomaticEDA document into a single self-contained Markdown file.
+
+    Args:
+        chapters_or_profile: a list of chapters (``Chapter`` dataclasses or
+            dicts) or an ``eda`` TableProfile dict (chapters built via
+            ``build_document(profile, meta['ctx'])``).
+        out_path: filesystem path for the ``.md`` (parent dirs are created).
+        meta: optional dict. Recognised keys: ``title``, ``ctx`` (dict with
+            ``dataset_name``/``source_origin``/``storage``/``n_rows``/``n_cols``),
+            ``generated_at``, ``embed_figures`` (export PNGs beside the .md,
+            default False — off keeps the Markdown self-contained).
+
+    Returns:
+        dict (never raises): ``{path: str|None, n_chars: int,
+        chapters: list[{id, version}], note: str}``. On a fatal error ``path`` is
+        None and ``note`` explains the cause.
+    """
+    meta = dict(meta or {})
+    chapters = _coerce_chapters(chapters_or_profile, meta)
+    return render_md(chapters, out_path, meta)

python/functions/datascience/render_automatic_eda_markdown_test.py

@@ -0,0 +1,168 @@
+"""Tests for render_automatic_eda_markdown — DoD: golden + edge + profile path.
+
+Self-contained synthetic blocks (no DuckDB). Verifies every block kind serializes
+to Markdown (heading, markdown with glossary+bold, kv/data tables, a figure whose
+histogram bars become a data table, caption, note, group, glossary entry), that a
+leading level-1 heading equal to the chapter title is omitted, that an empty
+document degrades to a valid minimal Markdown without raising, and that passing a
+minimal TableProfile builds chapters and writes the file.
+"""
+
+import os
+import tempfile
+
+from datascience.render_automatic_eda_markdown import render_automatic_eda_markdown
+from datascience.automatic_eda.model import (
+    Caption, Chapter, DataTable, Figure, GlossaryEntry, Group, Heading, KVTable,
+    Markdown, Note,
+)
+
+
+def _hist_fig():
+    import matplotlib
+    matplotlib.use("Agg")
+    import matplotlib.pyplot as plt
+    fig, ax = plt.subplots()
+    ax.hist([1, 1, 2, 2, 2, 3, 4, 4, 5, 5, 5, 5], bins=5)
+    return fig
+
+
+def _chapters() -> list:
+    blocks = [
+        Heading("Demo", 1),                       # == chapter title -> omitted.
+        Heading("Seccion dos", 2),                # -> ####
+        Markdown("Texto con [[term:ent]]entropia[[/term]] y **bold** aqui."),
+        KVTable(rows=[("Filas", 1000), ("Columnas", 5)], title="Resumen"),
+        DataTable(header=["col", "valor"],
+                  rows=[["alpha", "111"], ["beta", "222"], ["gamma", "333"]],
+                  title="Datos", note="nota inferior"),
+        Figure(make=_hist_fig, caption="Histograma demo"),
+        Caption("pie de figura"),
+        Note("una nota aparte"),
+        Group(title="Grupo X", blocks=[Markdown("dentro del grupo")]),
+        GlossaryEntry(key="ent", label="Entropia",
+                      definition="Medida de incertidumbre."),
+    ]
+    return [Chapter(id="demo", title="Demo", version="1.0.0", blocks=blocks)]
+
+
+def _read(path: str) -> str:
+    with open(path, "r", encoding="utf-8") as fh:
+        return fh.read()
+
+
+def test_golden_bloques_sinteticos_serializa_todo_a_markdown():
+    with tempfile.TemporaryDirectory() as d:
+        out = os.path.join(d, "demo.md")
+        res = render_automatic_eda_markdown(
+            _chapters(), out,
+            {"title": "EDA Demo",
+             "ctx": {"dataset_name": "Demo", "n_rows": 12, "n_cols": 2}})
+        assert res["path"] == out
+        assert os.path.exists(out)
+        assert res["n_chars"] > 0
+        assert res["chapters"] == [{"id": "demo", "version": "1.0.0"}]
+
+        content = _read(out)
+        # Document structure.
+        assert content.startswith("# ")
+        assert "## Índice" in content
+        # A Markdown table is present (header + separator row).
+        assert "| " in content and "| --- " in content
+        # DataTable values are all dumped.
+        for v in ("alpha", "111", "beta", "222", "gamma", "333"):
+            assert v in content
+        # Glossary markers stripped, bold kept.
+        assert "[[term" not in content
+        assert "[[/term]]" not in content
+        assert "**bold**" in content
+        assert "entropia" in content  # visible glossary text preserved.
+        # Figure histogram bars became a data table.
+        assert "| Desde | Hasta | Frecuencia |" in content
+        # Glossary entry rendered as a level-3 heading.
+        assert "### Entropia" in content
+        # Level-2 heading -> ####.
+        assert "#### Seccion dos" in content
+        # Leading level-1 heading equal to the title was omitted.
+        assert "### Demo" not in content
+        # Group title rendered.
+        assert "### Grupo X" in content
+
+
+def _hist_fig_with_span():
+    """Histogram with a wide ``axvspan`` (±1σ band) over it.
+
+    Reproduces the num_distr figure shape: matplotlib keeps the span as a lone
+    Rectangle in ``ax.patches`` alongside the bin bars; it must NOT leak into the
+    extracted bins table as a fake bin (it is ~5x wider than a bin)."""
+    import matplotlib
+    matplotlib.use("Agg")
+    import matplotlib.pyplot as plt
+    fig, ax = plt.subplots()
+    data = [1, 1, 2, 2, 2, 3, 4, 4, 5, 5, 5, 5]
+    ax.hist(data, bins=5)
+    ax.axvspan(2.0, 4.0, alpha=0.2)   # mean±σ band — a wide stray rectangle.
+    return fig
+
+
+def test_figura_descarta_axvspan_de_la_tabla_de_bins():
+    """The ±1σ band rectangle must not appear as a row in the bins table."""
+    blocks = [Figure(make=_hist_fig_with_span, caption="Hist con banda")]
+    chapters = [Chapter(id="f", title="Fig", version="1.0.0", blocks=blocks)]
+    with tempfile.TemporaryDirectory() as d:
+        out = os.path.join(d, "fig.md")
+        render_automatic_eda_markdown(chapters, out, {"title": "T"})
+        content = _read(out)
+        assert "| Desde | Hasta | Frecuencia |" in content
+        # Extract the rows of the bins table: lines between the header/separator
+        # and the next blank line.
+        lines = content.splitlines()
+        hi = next(i for i, ln in enumerate(lines)
+                  if ln.startswith("| Desde | Hasta | Frecuencia |"))
+        rows = []
+        for ln in lines[hi + 2:]:           # skip header + separator
+            if not ln.startswith("|"):
+                break
+            rows.append(ln)
+        # 5 histogram bins, no extra wide span row.
+        assert len(rows) == 5, rows
+        # No row spans a width of ~2.0 (the axvspan from x=2 to x=4).
+        for ln in rows:
+            cells = [c.strip() for c in ln.strip("|").split("|")]
+            lo, hi_v = float(cells[0]), float(cells[1])
+            assert (hi_v - lo) < 1.5, f"wide span leaked: {ln}"
+
+
+def test_edge_documento_vacio_no_revienta():
+    with tempfile.TemporaryDirectory() as d:
+        out = os.path.join(d, "empty.md")
+        res = render_automatic_eda_markdown([], out, {})
+        assert res["path"] == out
+        assert os.path.exists(out)
+        assert res["chapters"] == []
+        content = _read(out)
+        assert "documento vacío" in content
+        assert content.startswith("# ")
+
+
+def test_profile_path_construye_capitulos_y_escribe():
+    profile = {
+        "table": "mini",
+        "source": "/data/mini.csv",
+        "n_rows": 10,
+        "n_cols": 1,
+        "quality_score": 88.0,
+        "columns": [
+            {"name": "x", "inferred_type": "numeric", "null_pct": 0.0,
+             "null_count": 0,
+             "numeric": {"mean": 1.0, "median": 1.0, "min": 0.0, "max": 2.0,
+                         "std": 0.5}},
+        ],
+    }
+    with tempfile.TemporaryDirectory() as d:
+        out = os.path.join(d, "mini.md")
+        res = render_automatic_eda_markdown(
+            profile, out, {"title": "Mini", "ctx": {"dataset_name": "Mini"}})
+        assert res["path"] == out  # not None — no exception, file written.
+        assert os.path.exists(out)
+        assert res["n_chars"] > 0

python/functions/pipelines/render_automatic_eda.py

@@ -1,9 +1,10 @@
-"""render_automatic_eda — EDA completo one-shot: perfil → ctx → PDF + PPTX.
+"""render_automatic_eda — EDA completo one-shot: perfil → ctx → PDF + PPTX + MD.
 
 Pipeline impuro del grupo de capacidad `eda`. Dada UNA tabla DuckDB (o
-PostgreSQL), produce el informe AutomaticEDA COMPLETO en sus dos formatos a la
-vez (PDF móvil A5 + PPTX 16:9) con los 11 capítulos POBLADOS, en una sola
-llamada. Compone, sin reimplementar su lógica, cuatro funciones del registry:
+PostgreSQL), produce el informe AutomaticEDA COMPLETO en sus tres formatos a la
+vez (PDF móvil A5 + PPTX 16:9 + Markdown autocontenido para pegar a un LLM) con
+los capítulos POBLADOS, en una sola llamada. Compone, sin reimplementar su
+lógica, varias funciones del registry:
 
   - profile_table          : perfila la tabla end-to-end (TableProfile agregado),
                              opcionalmente con modelos baratos y análisis de serie.
@@ -12,8 +13,11 @@ llamada. Compone, sin reimplementar su lógica, cuatro funciones del registry:
                              modelos/geo, timeseries_raw para series, geo_points
                              para el mapa, db_path/table para la agregación
                              push-down). Sin él, esos capítulos degradan.
-  - render_automatic_eda_pdf  : renderiza el documento por capítulos a PDF.
-  - render_automatic_eda_pptx : renderiza el mismo documento a PPTX.
+  - render_automatic_eda_pdf      : renderiza el documento por capítulos a PDF.
+  - render_automatic_eda_pptx     : renderiza el mismo documento a PPTX.
+  - render_automatic_eda_markdown : serializa el mismo documento a Markdown
+                                    autocontenido (texto + tablas markdown, sin
+                                    binarios) para incorporar a un LLM.
 
 El TableProfile agregado basta para portada/overview/distribuciones/calidad/
 correlación, pero los capítulos `modelos`, `timeseries`, `geospatial` y
@@ -32,6 +36,7 @@ from datetime import datetime, timezone
 
 from datascience import (
     build_eda_render_ctx,
+    render_automatic_eda_markdown,
     render_automatic_eda_pdf,
     render_automatic_eda_pptx,
     run_eda_models,
@@ -93,6 +98,7 @@ def render_automatic_eda(
     out_dir: str = "reports",
     basename: str = None,
     ctx_extra: dict = None,
+    emit_md: bool = True,
 ) -> dict:
     """Perfila una tabla y emite el informe AutomaticEDA completo (PDF + PPTX).
 
@@ -140,13 +146,19 @@ def render_automatic_eda(
         ctx_extra: dict opcional con claves de presentación/contexto extra que se
             mezclan en el ctx (p.ej. dataset_name, description, source_origin).
             No pisan las claves de datos calculadas por build_eda_render_ctx.
+        emit_md: además del PDF y el PPTX, emite un Markdown autocontenido del
+            MISMO documento por capítulos (texto plano + tablas markdown, sin
+            binarios), pensado para pegar a un LLM. Default True. La ruta sale en
+            la clave de retorno ``aeda_md_path``. No altera las demás salidas.
 
     Returns:
         dict (nunca lanza). En éxito::
 
             {"status": "ok", "pdf_path": str, "pptx_path": str,
-             "manifest_path": str|None, "n_pages": int, "n_slides": int,
-             "pdf_note": str, "pptx_note": str, "profile": <TableProfile>}
+             "aeda_md_path": str|None, "manifest_path": str|None,
+             "n_pages": int, "n_slides": int, "md_chars": int|None,
+             "pdf_note": str, "pptx_note": str, "md_note": str|None,
+             "profile": <TableProfile>}
 
         En error: {"status": "error", "error": str}.
     """
@@ -243,15 +255,26 @@ def render_automatic_eda(
         rpdf = render_automatic_eda_pdf(prof, pdf_path, meta) or {}
         rpptx = render_automatic_eda_pptx(prof, pptx_path, meta) or {}
 
+        # Salida Markdown autocontenida (mismo documento por capítulos) para
+        # pegar a un LLM. Aditiva: no afecta a PDF/PPTX/manifest. dict-no-throw.
+        rmd = {}
+        md_path = None
+        if emit_md:
+            md_path = os.path.join(out_dir, base + ".md")
+            rmd = render_automatic_eda_markdown(prof, md_path, meta) or {}
+
         return {
             "status": "ok",
             "pdf_path": rpdf.get("path"),
             "pptx_path": rpptx.get("path"),
+            "aeda_md_path": rmd.get("path"),
             "manifest_path": rpdf.get("manifest_path"),
             "n_pages": rpdf.get("n_pages"),
             "n_slides": rpptx.get("n_slides"),
+            "md_chars": rmd.get("n_chars"),
             "pdf_note": rpdf.get("note"),
             "pptx_note": rpptx.get("note"),
+            "md_note": rmd.get("note"),
             "profile": prof,
         }
     except Exception as e:  # noqa: BLE001 — dict-no-throw: degradar, nunca lanzar.