diff --git a/python/functions/datascience/__init__.py b/python/functions/datascience/__init__.py
index 60f5260d..7440171e 100644
--- a/python/functions/datascience/__init__.py
+++ b/python/functions/datascience/__init__.py
@@ -60,8 +60,16 @@ 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 .detect_time_column import detect_time_column
+from .extract_timeseries_raw import extract_timeseries_raw
+from .profile_datetime import profile_datetime
+from .resample_timeseries import resample_timeseries
 
 __all__ = [
+    "detect_time_column",
+    "extract_timeseries_raw",
+    "profile_datetime",
+    "resample_timeseries",
     "render_automatic_eda_pdf",
     "render_automatic_eda_pptx",
     "decode_qr_image",
diff --git a/python/functions/datascience/automatic_eda/chapters/timeseries.py b/python/functions/datascience/automatic_eda/chapters/timeseries.py
new file mode 100644
index 00000000..150eb03e
--- /dev/null
+++ b/python/functions/datascience/automatic_eda/chapters/timeseries.py
@@ -0,0 +1,613 @@
+"""Time-series chapter (TIMESERIES) for AutomaticEDA.
+
+This chapter applies **only when the table has a date/datetime column**. When it
+does, it draws — exactly the user requirement — the evolution of the data over
+time (the value of each numeric column aggregated per period *and* the count of
+rows per period) plus the statistical analysis of the series (stationarity,
+autocorrelation, trend and seasonality). When there is no temporal column
+``build_timeseries`` returns ``None``.
+
+Data sources, read defensively and never recomputed here:
+
+- ``profile['columns']`` — to detect the time column and the numeric columns.
+  Delegated to the pure registry function ``detect_time_column`` (group ``eda``).
+- ``profile['series'][col]`` — the per-column time-series analysis already
+  produced by ``profile_table(run_series=True)``: ``stationarity`` (ADF+KPSS),
+  ``acf_pacf`` (ACF/PACF + Ljung-Box), ``stl`` (trend/seasonal/resid +
+  Hyndman strengths) and the levels/returns suggestion.
+- ``ctx['timeseries_raw']`` (or ``profile['timeseries_raw']``) — the *raw* ordered
+  series ``{time_col, t:[iso...], series:{col:[float|None]}}`` needed to draw the
+  value-vs-time line and the per-period row count. Exactly like ``modelos`` reads
+  ``raw_numeric`` from ``ctx``, this chapter looks for the raw series there and
+  degrades honestly when it is absent (it still renders the textual analysis).
+
+The raw series is aggregated per period with the pure registry function
+``resample_timeseries`` and the datetime header is built with ``profile_datetime``
+(both group ``eda``). Every figure is emitted as a lazy ``Figure`` so the
+renderers rasterize and scale it to fit a whole page/slide; tables go through
+``DataTable``/``KVTable`` so the paginator splits them repeating the header. No
+content is ever cut.
+
+ctx keys this chapter consumes (all optional):
+    timeseries_raw : dict — ``{time_col, t:[...], series:{col:[...]}}`` raw
+        ordered series used to draw the value-vs-time line and the row-count
+        panel. When absent the chapter omits those figures (with a note) and
+        renders only the analysis available in ``profile['series']``.
+
+Contract: build_<id>(profile, ctx) -> Chapter | None ; CHAPTER_VERSION = "x.y.z".
+Reads everything defensively (``.get``) and never raises.
+"""
+
+from __future__ import annotations
+
+from .. import model
+
+# Pure/impure registry functions (group ``eda``) consumed by this chapter,
+# imported defensively so the chapter still builds (degrading the affected
+# section to a note) if any of them is somehow unavailable.
+try:
+    from datascience.detect_time_column import detect_time_column
+except Exception:  # noqa: BLE001 — keep the chapter importable no matter what.
+    detect_time_column = None  # type: ignore[assignment]
+try:
+    from datascience.profile_datetime import profile_datetime
+except Exception:  # noqa: BLE001
+    profile_datetime = None  # type: ignore[assignment]
+try:
+    from datascience.resample_timeseries import resample_timeseries
+except Exception:  # noqa: BLE001
+    resample_timeseries = None  # type: ignore[assignment]
+
+CHAPTER_VERSION = "1.0.0"
+CHAPTER_ID = "timeseries"
+CHAPTER_TITLE = "Series temporales"
+
+# Plain-Spanish gloss for the stationarity verdict of adf_kpss_stationarity.
+_VERDICT_GLOSS = {
+    "stationary": "estacionaria: media y varianza estables en el tiempo; se "
+                  "puede modelar directamente.",
+    "non_stationary": "no estacionaria: tiene tendencia o varianza cambiante "
+                      "(raíz unitaria). Correlacionar o modelar sus niveles "
+                      "produce relaciones espurias (Granger-Newbold); conviene "
+                      "diferenciar o pasar a retornos.",
+    "inconclusive": "resultado no concluyente (ADF y KPSS discrepan): tratar con "
+                    "cautela, probablemente cerca de la no estacionariedad.",
+}
+
+# OHLC-style name fragments used to collapse near-identical financial series.
+_OHLC_HINTS = ("open", "high", "low", "close", "adj", "price", "vwap")
+
+
+def _fmt_num(value, decimals: int = 3) -> str:
+    """Compact, defensive number formatting shared with the other chapters."""
+    if value is None:
+        return "—"
+    if isinstance(value, bool):
+        return "sí" if value else "no"
+    if isinstance(value, int):
+        return f"{value:,}".replace(",", ".")
+    if isinstance(value, float):
+        if value != value:  # NaN
+            return "NaN"
+        if value in (float("inf"), float("-inf")):
+            return str(value)
+        text = f"{value:.{decimals}f}".rstrip("0").rstrip(".")
+        return text if text else "0"
+    return model._safe_str(value)
+
+
+def _is_dict(v) -> bool:
+    return isinstance(v, dict)
+
+
+# --------------------------------------------------------------------------- #
+# Detection: which column is the time axis and which numeric columns to chart.
+# --------------------------------------------------------------------------- #
+def _detect(cols: list) -> dict:
+    """Return ``{time_col, numeric_cols, ...}`` via the registry function.
+
+    Falls back to an inline scan (datetime inferred_type / datetime semantic
+    types) when ``detect_time_column`` is unavailable, so the chapter still works.
+    """
+    if detect_time_column is not None:
+        try:
+            res = detect_time_column(cols)
+            if _is_dict(res):
+                return res
+        except Exception:  # noqa: BLE001 — degrade to the inline scan.
+            pass
+    time_col = None
+    numeric_cols = []
+    for c in cols or []:
+        if not _is_dict(c):
+            continue
+        it = c.get("inferred_type")
+        sem = c.get("semantic_type")
+        if time_col is None and (
+                it == "datetime" or sem in ("datetime_iso", "date_eu")):
+            time_col = c.get("name")
+        if it == "numeric":
+            numeric_cols.append(c.get("name"))
+    return {"time_col": time_col, "numeric_cols": numeric_cols,
+            "time_semantic": "", "reason": "inline fallback"}
+
+
+def _raw_series_for(raw: dict, col: str):
+    """Return (t_list, v_list) for a column from the raw bundle, or (None, None)."""
+    if not _is_dict(raw):
+        return None, None
+    t = raw.get("t")
+    series = raw.get("series") if _is_dict(raw.get("series")) else {}
+    v = series.get(col)
+    if isinstance(t, list) and isinstance(v, list) and t and len(t) == len(v):
+        return t, v
+    return None, None
+
+
+def _ohlc_groups(numeric_cols: list, raw: dict) -> dict:
+    """Map each numeric column to a representative to collapse OHLC duplicates.
+
+    When several numeric columns are near-identical financial level series
+    (open/high/low/close/adj close), charting each one repeats the same figure
+    four times. We keep the first OHLC-looking column as the representative for
+    the *figures* and list the collapsed ones in a note; the textual analysis is
+    still produced for every column. Detection is by name only (cheap, no extra
+    data dependency) and conservative: only collapses when >=2 OHLC-like names
+    are present.
+    """
+    ohlc = [c for c in numeric_cols
+            if isinstance(c, str) and any(h in c.lower() for h in _OHLC_HINTS)]
+    if len(ohlc) < 2:
+        return {}
+    representative = ohlc[0]
+    return {c: representative for c in ohlc if c != representative}
+
+
+# --------------------------------------------------------------------------- #
+# Datetime header (MUST-9.3): range / frequency / regularity / gaps.
+# --------------------------------------------------------------------------- #
+def _datetime_header(time_col: str, raw: dict) -> list:
+    """Build the datetime profile header from the raw time axis, when present."""
+    blocks: list = []
+    t, _ = (raw.get("t"), None) if _is_dict(raw) else (None, None)
+    if not (isinstance(t, list) and t and profile_datetime is not None):
+        return blocks
+    try:
+        dt = profile_datetime(t)
+    except Exception:  # noqa: BLE001
+        return blocks
+    if not _is_dict(dt):
+        return blocks
+
+    freq_gloss = {
+        "daily": "diaria", "weekly": "semanal", "monthly": "mensual",
+        "quarterly": "trimestral", "yearly": "anual",
+        "irregular": "irregular", "unknown": "indeterminada",
+    }
+    rows = [
+        ("Columna de fecha", model._safe_str(time_col)),
+        ("Rango", f"{model._safe_str(dt.get('min'))} → "
+                  f"{model._safe_str(dt.get('max'))}"),
+        ("Observaciones", _fmt_num(dt.get("n"))),
+        ("Fechas distintas", _fmt_num(dt.get("n_distinct"))),
+        ("Frecuencia", freq_gloss.get(dt.get("freq"), model._safe_str(dt.get("freq")))),
+        ("Regular", "sí" if dt.get("is_regular") else "no"),
+    ]
+    span = dt.get("span_days")
+    if span is not None:
+        rows.append(("Duración (días)", _fmt_num(span, 1)))
+    n_gaps = dt.get("n_gaps")
+    if n_gaps is not None:
+        rows.append(("Huecos en la rejilla", _fmt_num(n_gaps)))
+    blocks.append(model.KVTable(rows=rows, title="Perfil temporal"))
+    note = dt.get("note")
+    if note:
+        blocks.append(model.Note(model._safe_str(note)))
+    return blocks
+
+
+# --------------------------------------------------------------------------- #
+# Figure builders (lazy: matplotlib only imported when the renderer draws them).
+# --------------------------------------------------------------------------- #
+def _parse_dates(labels: list):
+    """Parse a list of ISO-ish strings/dates to datetime, dropping unparseable.
+
+    Returns (dates, kept_index) so callers can align the values list.
+    """
+    from datetime import date, datetime
+
+    out = []
+    keep = []
+    for i, lab in enumerate(labels):
+        if isinstance(lab, datetime):
+            out.append(lab)
+            keep.append(i)
+            continue
+        if isinstance(lab, date):
+            out.append(datetime(lab.year, lab.month, lab.day))
+            keep.append(i)
+            continue
+        s = model._safe_str(lab).strip()
+        if not s:
+            continue
+        s2 = s.replace("T", " ")
+        parsed = None
+        for fmt in ("%Y-%m-%d %H:%M:%S", "%Y-%m-%d %H:%M", "%Y-%m-%d"):
+            try:
+                parsed = datetime.strptime(s2[:len(fmt) + 4] if False else s2, fmt)
+                break
+            except ValueError:
+                continue
+        if parsed is None:
+            try:
+                parsed = datetime.fromisoformat(s.replace("T", " "))
+            except ValueError:
+                continue
+        out.append(parsed)
+        keep.append(i)
+    return out, keep
+
+
+def _make_evolution_figure(name: str, rs: dict):
+    """Lazy callable: value-vs-time line + per-period row-count panel (MUST-9.1)."""
+    def _draw():
+        import matplotlib
+        matplotlib.use("Agg")
+        import matplotlib.pyplot as plt
+        import matplotlib.dates as mdates
+
+        t_labels = rs.get("t") or []
+        v = rs.get("v") or []
+        counts = rs.get("count") or []
+        dates, keep = _parse_dates(t_labels)
+        vv = [v[i] if i < len(v) else None for i in keep]
+        cc = [counts[i] if i < len(counts) else 0 for i in keep]
+
+        fig, (ax_v, ax_c) = plt.subplots(
+            2, 1, figsize=(7.0, 4.6), sharex=True,
+            gridspec_kw={"height_ratios": [3.0, 1.2], "hspace": 0.12})
+
+        # Top: value aggregated per period (line; gaps where the value is None).
+        xs = [d for d, val in zip(dates, vv) if val is not None]
+        ys = [val for val in vv if val is not None]
+        if xs and ys:
+            ax_v.plot(xs, ys, color="#4e79a7", linewidth=1.4, zorder=3)
+            ax_v.fill_between(xs, ys, min(ys), color="#9ec6df", alpha=0.18,
+                              zorder=1)
+        else:
+            ax_v.text(0.5, 0.5, "(sin valores numéricos)", ha="center",
+                      va="center", fontsize=9, color="#8a8a8a",
+                      transform=ax_v.transAxes)
+        ax_v.set_ylabel(name, fontsize=8)
+        ax_v.tick_params(labelsize=7)
+        ax_v.grid(axis="y", color="#eeeeee", linewidth=0.6)
+        for spine in ("top", "right"):
+            ax_v.spines[spine].set_visible(False)
+
+        # Bottom: number of observations per period (density / gaps).
+        if dates and cc:
+            # Bar width ~ median spacing so bars do not overlap nor leave gaps.
+            width = 1.0
+            if len(dates) > 1:
+                deltas = sorted((dates[i + 1] - dates[i]).days
+                                for i in range(len(dates) - 1))
+                width = max(deltas[len(deltas) // 2] * 0.8, 1.0)
+            ax_c.bar(dates, cc, width=width, color="#59a14f", alpha=0.75,
+                     align="center")
+        ax_c.set_ylabel("nº filas", fontsize=8)
+        ax_c.tick_params(labelsize=7)
+        ax_c.grid(axis="y", color="#eeeeee", linewidth=0.6)
+        for spine in ("top", "right"):
+            ax_c.spines[spine].set_visible(False)
+
+        ax_c.xaxis.set_major_locator(mdates.AutoDateLocator())
+        ax_c.xaxis.set_major_formatter(mdates.ConciseDateFormatter(
+            ax_c.xaxis.get_major_locator()))
+        freq = rs.get("freq")
+        suptitle = f"{name} — evolución temporal"
+        if freq:
+            suptitle += f" (agregado {freq})"
+        fig.suptitle(suptitle, fontsize=10, fontweight="bold", x=0.02, ha="left")
+        return fig
+
+    return _draw
+
+
+def _make_stl_figure(stl: dict):
+    """Lazy callable: the STL trend/seasonal/resid panels, or None if no values.
+
+    ``stl_decompose`` only carries the component *values* for short series; for
+    long ones it returns just summary stats (``note``). In that case there is
+    nothing to plot and we return None (the caller renders the strengths as text).
+    """
+    def _component_values(comp):
+        if _is_dict(comp):
+            vals = comp.get("values")
+            if isinstance(vals, list) and vals:
+                return [x for x in vals]
+        return None
+
+    trend = _component_values(stl.get("trend"))
+    seasonal = _component_values(stl.get("seasonal"))
+    resid = _component_values(stl.get("resid"))
+    if not any([trend, seasonal, resid]):
+        return None
+
+    def _draw():
+        import matplotlib
+        matplotlib.use("Agg")
+        import matplotlib.pyplot as plt
+
+        panels = [("Tendencia", trend, "#4e79a7"),
+                  ("Estacional", seasonal, "#59a14f"),
+                  ("Resto", resid, "#e15759")]
+        panels = [(lbl, vals, col) for lbl, vals, col in panels if vals]
+        fig, axes = plt.subplots(len(panels), 1, figsize=(7.0, 1.4 * len(panels) + 0.6),
+                                 sharex=True)
+        if len(panels) == 1:
+            axes = [axes]
+        for ax, (lbl, vals, col) in zip(axes, panels):
+            ax.plot(range(len(vals)), vals, color=col, linewidth=1.2)
+            ax.set_ylabel(lbl, fontsize=8)
+            ax.tick_params(labelsize=7)
+            ax.grid(axis="y", color="#eeeeee", linewidth=0.6)
+            for spine in ("top", "right"):
+                ax.spines[spine].set_visible(False)
+        axes[-1].set_xlabel("índice temporal", fontsize=8)
+        fig.suptitle("Descomposición STL", fontsize=10, fontweight="bold",
+                     x=0.02, ha="left")
+        fig.tight_layout(rect=(0, 0, 1, 0.96))
+        return fig
+
+    return _draw
+
+
+def _make_acf_figure(acf_pacf: dict):
+    """Lazy callable: the ACF stem plot with ±1.96/√n bands, or None."""
+    acf = acf_pacf.get("acf")
+    n = acf_pacf.get("n")
+    if not (isinstance(acf, list) and len(acf) > 1 and isinstance(n, int) and n > 0):
+        return None
+
+    def _draw():
+        import math
+        import matplotlib
+        matplotlib.use("Agg")
+        import matplotlib.pyplot as plt
+
+        lags = list(range(len(acf)))
+        fig, ax = plt.subplots(figsize=(7.0, 3.2))
+        ax.vlines(lags, 0, acf, color="#4e79a7", linewidth=1.4)
+        ax.plot(lags, acf, "o", color="#4e79a7", markersize=3)
+        band = 1.96 / math.sqrt(n)
+        ax.axhspan(-band, band, color="#cccccc", alpha=0.3,
+                   label="banda ±1.96/√n (ruido blanco)")
+        ax.axhline(0, color="#888888", linewidth=0.8)
+        ax.set_xlabel("retardo (lag)", fontsize=8)
+        ax.set_ylabel("ACF", fontsize=8)
+        ax.tick_params(labelsize=7)
+        ax.legend(fontsize=7, loc="upper right", framealpha=0.85)
+        ax.set_title("Autocorrelación (ACF): lags fuera de la banda = "
+                     "correlación significativa", fontsize=9)
+        fig.tight_layout()
+        return fig
+
+    return _draw
+
+
+# --------------------------------------------------------------------------- #
+# Per-column textual analysis from profile['series'][col].
+# --------------------------------------------------------------------------- #
+def _analysis_markdown(sblock: dict) -> str:
+    """One markdown block summarizing stationarity / autocorrelation / STL."""
+    parts: list = []
+
+    stat = sblock.get("stationarity") if _is_dict(sblock.get("stationarity")) else {}
+    verdict = stat.get("verdict")
+    if verdict:
+        adf = stat.get("adf") if _is_dict(stat.get("adf")) else {}
+        kpss = stat.get("kpss") if _is_dict(stat.get("kpss")) else {}
+        line = (f"**Estacionariedad:** {_VERDICT_GLOSS.get(verdict, verdict)} "
+                f"(ADF p={_fmt_num(adf.get('p_value'), 4)}, "
+                f"KPSS p={_fmt_num(kpss.get('p_value'), 4)}).")
+        warning = stat.get("warning")
+        if warning:
+            line += f" ⚠ {model._safe_str(warning)}"
+        parts.append(line)
+
+    acf = sblock.get("acf_pacf") if _is_dict(sblock.get("acf_pacf")) else {}
+    if acf:
+        is_auto = acf.get("is_autocorrelated")
+        lb = acf.get("ljung_box") if _is_dict(acf.get("ljung_box")) else {}
+        sig = acf.get("significant_acf_lags") or []
+        if is_auto is True:
+            ac_line = ("**Autocorrelación:** la serie está autocorrelada "
+                       "(Ljung-Box rechaza independencia, "
+                       f"p={_fmt_num(lb.get('p_value'), 4)}): los valores dependen "
+                       "de su pasado, no es ruido blanco.")
+            if sig:
+                shown = ", ".join(str(x) for x in sig[:8])
+                more = "…" if len(sig) > 8 else ""
+                ac_line += f" Lags significativos: {shown}{more}."
+        elif is_auto is False:
+            ac_line = ("**Autocorrelación:** no se detecta autocorrelación "
+                       "significativa (compatible con ruido blanco, Ljung-Box "
+                       f"p={_fmt_num(lb.get('p_value'), 4)}).")
+        else:
+            ac_line = "**Autocorrelación:** no evaluable (datos insuficientes)."
+        parts.append(ac_line)
+
+    stl = sblock.get("stl") if _is_dict(sblock.get("stl")) else {}
+    if stl:
+        ts = stl.get("trend_strength")
+        ss = stl.get("seasonal_strength")
+        if ts is not None or ss is not None:
+            parts.append(
+                "**Descomposición STL:** fuerza de tendencia "
+                f"{_fmt_num(ts, 2)} y fuerza estacional {_fmt_num(ss, 2)} "
+                "(escala 0–1 de Hyndman: cuanto más alto, más marcada la "
+                "componente).")
+        elif stl.get("note"):
+            parts.append(f"**Descomposición STL:** {model._safe_str(stl.get('note'))}")
+
+    if sblock.get("levels_suggested"):
+        reason = sblock.get("levels_reason")
+        kind = sblock.get("levels_kind")
+        tr = sblock.get("to_returns") if _is_dict(sblock.get("to_returns")) else None
+        line = "**Transformación sugerida:** "
+        line += "pasar a retornos" if kind == "returns" else "diferenciar la serie"
+        if reason:
+            line += f" — {model._safe_str(reason)}"
+        if tr and tr.get("mean") is not None:
+            line += (f" (retornos: media {_fmt_num(tr.get('mean'), 5)}, "
+                     f"σ {_fmt_num(tr.get('std'), 5)}).")
+        parts.append(line)
+
+    return "\n\n".join(parts)
+
+
+# --------------------------------------------------------------------------- #
+# Per-column section.
+# --------------------------------------------------------------------------- #
+def _column_section(name: str, sblock: dict, raw: dict, collapsed_into) -> list:
+    """Blocks for one numeric column: evolution figure + STL + ACF + analysis."""
+    blocks = [model.Heading(text=model._safe_str(name), level=2)]
+
+    # --- Value-vs-time line + per-period row count (MUST-9.1). ---
+    drew_evolution = False
+    if collapsed_into is None:  # skip the figure for collapsed OHLC duplicates.
+        t, v = _raw_series_for(raw, name)
+        if t is not None and resample_timeseries is not None:
+            try:
+                rs = resample_timeseries(t, v)
+            except Exception:  # noqa: BLE001
+                rs = None
+            if _is_dict(rs) and rs.get("t"):
+                blocks.append(model.Figure(
+                    make=_make_evolution_figure(name, rs),
+                    caption=f"Evolución de «{name}» por periodo y nº de "
+                            f"observaciones (conteo de filas)."))
+                drew_evolution = True
+    else:
+        blocks.append(model.Note(
+            f"Serie casi idéntica a «{collapsed_into}» (grupo OHLC): se omite el "
+            "gráfico para no repetirlo; el análisis estadístico se mantiene."))
+
+    if not drew_evolution and collapsed_into is None:
+        blocks.append(model.Note(
+            "Gráfico de evolución temporal no disponible: falta la serie cruda "
+            "(pásala en ctx['timeseries_raw'] = {time_col, t, series}). Se "
+            "muestra solo el análisis estadístico."))
+
+    # --- STL panels (MUST-9.2). ---
+    stl = sblock.get("stl") if _is_dict(sblock.get("stl")) else {}
+    if collapsed_into is None and stl:
+        stl_fig = _make_stl_figure(stl)
+        if stl_fig is not None:
+            blocks.append(model.Figure(
+                make=stl_fig,
+                caption=f"Descomposición STL de «{name}»: tendencia, componente "
+                        f"estacional y resto."))
+
+    # --- ACF figure (autocorrelation structure). ---
+    acf = sblock.get("acf_pacf") if _is_dict(sblock.get("acf_pacf")) else {}
+    if collapsed_into is None and acf:
+        acf_fig = _make_acf_figure(acf)
+        if acf_fig is not None:
+            blocks.append(model.Figure(
+                make=acf_fig,
+                caption=f"Función de autocorrelación de «{name}»."))
+
+    # --- Textual analysis (always, even for collapsed duplicates). ---
+    analysis = _analysis_markdown(sblock)
+    if analysis:
+        blocks.append(model.Markdown(text=analysis))
+    return blocks
+
+
+# --------------------------------------------------------------------------- #
+# Entry point.
+# --------------------------------------------------------------------------- #
+def build_timeseries(profile: dict, ctx: dict):
+    """Build the TIMESERIES Chapter, or ``None`` if the table has no date column.
+
+    Args:
+        profile: the ``eda`` group TableProfile dict.
+        ctx: presentation context; ``ctx['timeseries_raw']`` (optional) carries
+            the raw ordered series used to draw the value-vs-time line and the
+            per-period row count.
+
+    Returns:
+        A ``model.Chapter`` with, per numeric column, the value-vs-time evolution
+        + row-count figure, the STL panels, the ACF figure and the statistical
+        analysis; or ``None`` when there is no temporal column (the chapter does
+        not apply).
+    """
+    profile = profile or {}
+    if not _is_dict(profile):
+        profile = {}
+    ctx = ctx or {}
+    cols = profile.get("columns") or []
+
+    det = _detect(cols)
+    time_col = det.get("time_col")
+    if not time_col:
+        return None  # no date/datetime column -> chapter does not apply.
+
+    numeric_cols = det.get("numeric_cols") or []
+    series_map = profile.get("series") if _is_dict(profile.get("series")) else {}
+    raw = ctx.get("timeseries_raw") or profile.get("timeseries_raw")
+    raw = raw if _is_dict(raw) else {}
+
+    # Which columns can the chapter say anything about: those with a series
+    # analysis block and/or a raw series to chart. Preserve the profile order.
+    chartable = []
+    for name in numeric_cols:
+        has_analysis = _is_dict(series_map.get(name))
+        has_raw, _ = _raw_series_for(raw, name)
+        if has_analysis or has_raw is not None:
+            chartable.append(name)
+    if not chartable:
+        # A date column exists but nothing numeric to chart/analyse: still a
+        # valid (small) chapter — show just the datetime header if we have it.
+        header = _datetime_header(time_col, raw)
+        if not header:
+            return None
+        intro = (
+            f"La tabla tiene una columna temporal («{time_col}») pero no hay "
+            "columnas numéricas con serie analizable.")
+        blocks = [model.Heading(text=CHAPTER_TITLE, level=1),
+                  model.Markdown(text=intro)] + header
+        return model.Chapter(id=CHAPTER_ID, title=CHAPTER_TITLE,
+                             version=CHAPTER_VERSION, blocks=blocks)
+
+    collapsed = _ohlc_groups(chartable, raw)
+
+    intro = (
+        "Este capítulo analiza la evolución de la tabla en el tiempo usando la "
+        f"columna de fecha «{time_col}». Para cada columna numérica se muestra su "
+        "**evolución por periodo** (valor agregado) junto al **número de filas por "
+        "periodo** (densidad de observaciones), su **descomposición STL** "
+        "(tendencia / estacionalidad / resto) y la **función de autocorrelación**; "
+        "debajo, el análisis de la serie: estacionariedad (ADF + KPSS), "
+        "autocorrelación (Ljung-Box) y, cuando procede, la transformación "
+        "sugerida (retornos o diferencias) para evitar correlaciones espurias.")
+
+    blocks = [model.Heading(text=CHAPTER_TITLE, level=1),
+              model.Markdown(text=intro)]
+    blocks += _datetime_header(time_col, raw)
+
+    if collapsed:
+        reps = sorted(set(collapsed.values()))
+        collapsed_names = ", ".join(sorted(collapsed.keys()))
+        blocks.append(model.Note(
+            f"Series OHLC casi idénticas detectadas ({collapsed_names}): se "
+            f"grafican consolidadas en «{', '.join(reps)}» para no repetir el "
+            "mismo gráfico; cada columna conserva su análisis estadístico."))
+
+    for name in chartable:
+        sblock = series_map.get(name) if _is_dict(series_map.get(name)) else {}
+        blocks += _column_section(name, sblock, raw, collapsed.get(name))
+
+    return model.Chapter(id=CHAPTER_ID, title=CHAPTER_TITLE,
+                         version=CHAPTER_VERSION, blocks=blocks)
diff --git a/python/functions/datascience/automatic_eda/chapters/timeseries_test.py b/python/functions/datascience/automatic_eda/chapters/timeseries_test.py
new file mode 100644
index 00000000..2e18c022
--- /dev/null
+++ b/python/functions/datascience/automatic_eda/chapters/timeseries_test.py
@@ -0,0 +1,244 @@
+"""Tests for the TIMESERIES chapter — DoD: golden + edges + anti-cut.
+
+Self-contained: builds synthetic ``series`` blocks (shaped like
+``profile_table(run_series=True)`` output) and a raw ``timeseries_raw`` bundle,
+with no DuckDB, so the suite is fast and deterministic. Verifies that the chapter:
+
+- returns ``None`` when there is no date/datetime column (the user requirement);
+- never raises on ``None``/empty/garbage input;
+- with a date column + raw series emits, per numeric column, the value-vs-time +
+  row-count evolution figure, the STL panels, the ACF figure and the textual
+  analysis (stationarity / autocorrelation / suggested transform);
+- collapses near-identical OHLC series into one chart while keeping every
+  column's analysis;
+- renders without cutting anything in both PDF and PPTX (every column heading
+  survives in the rendered output).
+"""
+
+import math
+import os
+import re
+import tempfile
+
+from pypdf import PdfReader
+
+from datascience.automatic_eda.chapters.timeseries import (
+    build_timeseries, CHAPTER_VERSION, _VERDICT_GLOSS,
+)
+from datascience.render_automatic_eda_pdf import render_automatic_eda_pdf
+from datascience.render_automatic_eda_pptx import render_automatic_eda_pptx
+
+
+# --------------------------------------------------------------------------- #
+# Synthetic fixtures shaped like the real profile_table(run_series=True) output.
+# --------------------------------------------------------------------------- #
+def _dates(n: int) -> list:
+    """n consecutive daily ISO date strings starting 2021-01-01."""
+    from datetime import date, timedelta
+
+    start = date(2021, 1, 1)
+    return [(start + timedelta(days=i)).isoformat() for i in range(n)]
+
+
+def _series_block(n=120, verdict="non_stationary", autocorr=True, levels=True,
+                  with_stl_values=True):
+    """A synthetic ``series`` block like _build_series_block produces."""
+    trend = [float(i) for i in range(n)]
+    seasonal = [math.sin(i / 6.0) for i in range(n)]
+    resid = [0.1 * ((-1) ** i) for i in range(n)]
+    acf = [1.0] + [max(0.0, 0.9 - 0.05 * k) for k in range(1, 21)]
+    block = {
+        "order_col": "fecha",
+        "ordered": True,
+        "n": n,
+        "stationarity": {
+            "n": n, "verdict": verdict,
+            "adf": {"p_value": 0.42, "stationary": False},
+            "kpss": {"p_value": 0.01, "stationary": False},
+            "warning": ("serie no estacionaria: riesgo de correlación espuria"
+                        if verdict != "stationary" else None),
+        },
+        "acf_pacf": {
+            "n": n, "nlags": 20, "acf": acf,
+            "significant_acf_lags": [1, 2, 3, 4, 5],
+            "ljung_box": {"stat": 123.4, "p_value": 0.0 if autocorr else 0.7,
+                          "lags": 20},
+            "is_autocorrelated": autocorr,
+        },
+        "period_source": "datetime_freq",
+        "stl": {
+            "n": n, "period": 7, "period_inferred": False, "robust": False,
+            "trend": {"values": trend} if with_stl_values else {
+                "note": "serie larga: solo estadisticos", "mean": 60.0},
+            "seasonal": {"values": seasonal} if with_stl_values else {"mean": 0.0},
+            "resid": {"values": resid} if with_stl_values else {"mean": 0.0},
+            "trend_strength": 0.95, "seasonal_strength": 0.42,
+        },
+    }
+    if levels:
+        block["levels_suggested"] = True
+        block["levels_kind"] = "returns"
+        block["levels_reason"] = ("columna financiera no estacionaria: usar "
+                                  "retornos evita correlación espuria.")
+        block["to_returns"] = {"method": "log", "mean": 0.001, "std": 0.02}
+    else:
+        block["levels_suggested"] = False
+    return block
+
+
+def _profile(numeric_names=("precio",), n=120, with_stl_values=True):
+    cols = [{"name": "fecha", "inferred_type": "datetime",
+             "semantic_type": "datetime_iso"}]
+    series_map = {}
+    for nm in numeric_names:
+        cols.append({"name": nm, "inferred_type": "numeric",
+                     "numeric": {"min": 1.0, "max": 200.0, "mean": 100.0,
+                                 "median": 95.0, "std": 40.0}})
+        series_map[nm] = _series_block(n=n, with_stl_values=with_stl_values)
+    return {"table": "cotizaciones", "n_rows": n, "n_cols": len(cols),
+            "columns": cols, "series": series_map}
+
+
+def _ctx_raw(numeric_names=("precio",), n=120):
+    t = _dates(n)
+    series = {}
+    for j, nm in enumerate(numeric_names):
+        series[nm] = [float(100 + i + 5 * j) for i in range(n)]
+    return {"timeseries_raw": {"time_col": "fecha", "t": t, "series": series}}
+
+
+def _pdf_text(path: str) -> str:
+    txt = "".join((pg.extract_text() or "") for pg in PdfReader(path).pages)
+    return re.sub(r"\s+", " ", txt)
+
+
+# --------------------------------------------------------------------------- #
+# Golden.
+# --------------------------------------------------------------------------- #
+def test_golden_estructura_y_figuras():
+    ch = build_timeseries(_profile(("precio",)), _ctx_raw(("precio",)))
+    assert ch is not None
+    assert ch.id == "timeseries"
+    assert ch.version == CHAPTER_VERSION
+    kinds = [b.kind for b in ch.blocks]
+    assert kinds[0] == "heading"          # chapter title
+    assert kinds[1] == "markdown"         # intro
+    assert "kv_table" in kinds            # datetime profile header (MUST-9.3)
+    # Per column: evolution figure + STL figure + ACF figure + analysis markdown.
+    figs = [b for b in ch.blocks if b.kind == "figure"]
+    assert len(figs) >= 3, "evolución + STL + ACF esperadas"
+    # Lazy makers must produce real matplotlib figures.
+    import matplotlib.pyplot as plt
+    for f in figs:
+        fig = f.make()
+        assert fig is not None
+        plt.close(fig)
+
+
+def test_golden_evolucion_tiene_dos_paneles_valor_y_conteo():
+    # MUST-9.1: the evolution figure has a value panel + a row-count panel.
+    ch = build_timeseries(_profile(("precio",)), _ctx_raw(("precio",)))
+    figs = [b for b in ch.blocks if b.kind == "figure"]
+    import matplotlib.pyplot as plt
+    fig = figs[0].make()  # first figure is the evolution one.
+    assert len(fig.axes) == 2, "panel de valor + panel de conteo de filas"
+    plt.close(fig)
+
+
+def test_golden_analisis_textual_presente():
+    ch = build_timeseries(_profile(("precio",)), _ctx_raw(("precio",)))
+    md = " ".join(b.text for b in ch.blocks if b.kind == "markdown")
+    assert "Estacionariedad" in md
+    assert "Autocorrelación" in md
+    assert "STL" in md
+    # Verdict gloss surfaced for the non-stationary preset.
+    assert _VERDICT_GLOSS["non_stationary"].split(":")[0] in md
+    # Levels/returns suggestion surfaced.
+    assert "retornos" in md.lower()
+
+
+# --------------------------------------------------------------------------- #
+# Edges.
+# --------------------------------------------------------------------------- #
+def test_edge_sin_columna_fecha_devuelve_none():
+    prof = {"columns": [
+        {"name": "precio", "inferred_type": "numeric", "numeric": {"mean": 1.0}},
+        {"name": "ciudad", "inferred_type": "categorical",
+         "categorical": {"top": []}},
+    ], "series": {"precio": _series_block()}}
+    assert build_timeseries(prof, {}) is None
+
+
+def test_edge_none_y_vacio_no_revienta():
+    assert build_timeseries(None, None) is None
+    assert build_timeseries({}, {}) is None
+    assert build_timeseries({"columns": []}, {}) is None
+    # Date column but nothing numeric/series and no raw -> None (nothing to say).
+    assert build_timeseries(
+        {"columns": [{"name": "fecha", "inferred_type": "datetime"}]}, {}) is None
+
+
+def test_edge_sin_raw_degrada_pero_mantiene_analisis():
+    # No ctx['timeseries_raw']: the chapter must still build (STL/ACF/analysis
+    # from the profile) and note that the evolution chart is unavailable.
+    ch = build_timeseries(_profile(("precio",)), {})
+    assert ch is not None
+    notes = " ".join(b.text for b in ch.blocks if b.kind == "note")
+    assert "evolución temporal no disponible" in notes
+    md = " ".join(b.text for b in ch.blocks if b.kind == "markdown")
+    assert "Estacionariedad" in md
+
+
+def test_edge_stl_solo_estadisticos_no_dibuja_panel_pero_no_revienta():
+    # Long series: STL carries only stats (no 'values') -> no STL figure, but the
+    # strengths still surface in the textual analysis.
+    ch = build_timeseries(_profile(("precio",), with_stl_values=False),
+                          _ctx_raw(("precio",)))
+    assert ch is not None
+    md = " ".join(b.text for b in ch.blocks if b.kind == "markdown")
+    assert "STL" in md
+
+
+# --------------------------------------------------------------------------- #
+# OHLC consolidation (MUST-9.3).
+# --------------------------------------------------------------------------- #
+def test_ohlc_consolidacion():
+    names = ("Open", "High", "Low", "Close")
+    ch = build_timeseries(_profile(names), _ctx_raw(names))
+    assert ch is not None
+    notes = " ".join(b.text for b in ch.blocks if b.kind == "note")
+    assert "OHLC" in notes
+    # Only the representative draws the evolution figure; the other 3 are collapsed
+    # so there are fewer evolution figures than columns.
+    captions = [b.caption or "" for b in ch.blocks if b.kind == "figure"]
+    evo = [c for c in captions if "Evolución" in c]
+    assert len(evo) < len(names), "las series OHLC deben consolidarse"
+    # Every column still has its analysis markdown (one heading per column).
+    headings = [b.text for b in ch.blocks if b.kind == "heading" and b.level == 2]
+    for nm in names:
+        assert nm in headings
+
+
+# --------------------------------------------------------------------------- #
+# Anti-cut: PDF + PPTX.
+# --------------------------------------------------------------------------- #
+def test_anti_corte_pdf_y_pptx():
+    names = tuple(f"serie_{i}" for i in range(6))
+    prof = _profile(names, n=90)
+    ctx = _ctx_raw(names, n=90)
+    ch = build_timeseries(prof, ctx)
+    col_headings = [b.text for b in ch.blocks if b.kind == "heading" and b.level == 2]
+    assert len(col_headings) == 6
+    with tempfile.TemporaryDirectory() as d:
+        pdf = os.path.join(d, "ts.pdf")
+        res_pdf = render_automatic_eda_pdf(
+            prof, pdf, {"ctx": ctx, "write_manifest": False})
+        assert res_pdf["path"] == pdf
+        txt = _pdf_text(pdf)
+        for nm in col_headings:
+            assert nm in txt, f"columna '{nm}' cortada/ausente en el PDF"
+        pptx = os.path.join(d, "ts.pptx")
+        res_pptx = render_automatic_eda_pptx(
+            prof, pptx, {"ctx": ctx, "write_manifest": False})
+        assert res_pptx["path"] == pptx
+        assert res_pptx["n_slides"] >= 6
diff --git a/python/functions/datascience/detect_time_column.md b/python/functions/datascience/detect_time_column.md
new file mode 100644
index 00000000..60d75994
--- /dev/null
+++ b/python/functions/datascience/detect_time_column.md
@@ -0,0 +1,68 @@
+---
+name: detect_time_column
+kind: function
+lang: py
+domain: datascience
+version: "1.0.0"
+purity: pure
+signature: "def detect_time_column(columns: list) -> dict"
+description: "Detecta, a partir de la lista de ColumnProfile de un TableProfile del grupo eda, cual es la columna de orden temporal y que columnas numericas hay para graficar una serie en el tiempo. Una columna es temporal si inferred_type=='datetime' o semantic_type in {datetime_iso, date_eu}; time_col es la primera temporal en orden. Es la pieza que usa el capitulo TIMESERIES del AutomaticEDA para decidir si aplica. Lectura defensiva dict-no-throw: nunca lanza, siempre devuelve las mismas claves."
+tags: [eda, timeseries, datetime, profiling, column-detection, automatic-eda, datascience, python]
+uses_functions: []
+uses_types: []
+returns: []
+returns_optional: false
+error_type: ""
+imports: []
+params:
+  - name: columns
+    desc: "lista de ColumnProfile dict de un TableProfile del grupo eda. Cada elemento suele tener name, inferred_type, semantic_type y numeric. Elementos que no sean dict se ignoran; None/no-lista/vacia -> dict 'no aplica'."
+output: "dict SIEMPRE con: time_col (str|None, columna temporal elegida = primera temporal), time_semantic (str, semantic_type de la temporal o ''), numeric_cols (list[str], columnas con inferred_type=='numeric' en orden), n_datetime_cols (int), datetime_cols (list[str], todas las temporales en orden de aparicion), reason (str en espanol explicando la eleccion). Nunca lanza excepcion."
+tested: true
+tests: ["test_golden_datetime_y_numericas", "test_deteccion_por_semantic_type_date_eu", "test_sin_columna_temporal", "test_columns_none_no_revienta", "test_columns_vacia_no_revienta", "test_columns_no_lista_no_revienta", "test_elementos_basura_se_ignoran", "test_varias_datetime_elige_la_primera"]
+test_file_path: "python/functions/datascience/detect_time_column_test.py"
+file_path: "python/functions/datascience/detect_time_column.py"
+---
+
+## Ejemplo
+
+```python
+from datascience import detect_time_column
+
+columns = [
+    {"name": "fecha", "inferred_type": "datetime", "semantic_type": "datetime_iso"},
+    {"name": "ventas", "inferred_type": "numeric"},
+    {"name": "unidades", "inferred_type": "numeric"},
+    {"name": "region", "inferred_type": "text"},
+]
+res = detect_time_column(columns)
+res["time_col"]       # -> "fecha"
+res["numeric_cols"]   # -> ["ventas", "unidades"]
+res["n_datetime_cols"]  # -> 1
+
+# Sin columna temporal: el capitulo TIMESERIES no aplica.
+detect_time_column([{"name": "id", "inferred_type": "numeric"}])["time_col"]  # -> None
+```
+
+## Cuando usarla
+
+Cuando el capitulo TIMESERIES del AutomaticEDA recibe un TableProfile y necesita
+decidir si la tabla admite analisis de serie temporal: si `time_col` es None no
+hay eje de tiempo y el capitulo se salta; si hay `time_col` y `numeric_cols`,
+úsalas como eje X (orden cronologico) y series Y. Tambien sirve para enrutar el
+resto del pipeline (acf_pacf / stl_decompose / adf_kpss_stationarity) sobre las
+columnas numericas detectadas.
+
+## Gotchas
+
+- Es pura y stdlib-only (sin numpy ni DuckDB): segura de llamar en cualquier paso.
+- `time_col` se elige por ORDEN de aparicion en la lista, no por "mejor candidata".
+  Si hay varias columnas datetime y quieres otra, filtra `datetime_cols` tu mismo.
+- Solo mira metadatos del perfil (`inferred_type`/`semantic_type`); no parsea ni
+  valida los valores reales de la columna. La calidad de la deteccion depende de
+  que el profiler (summarize_table_duckdb / infer_semantic_type) haya inferido bien.
+- Las claves del semantic_type son exactamente las del profiler: `datetime_iso`
+  (ISO 8601) y `date_eu` (DD/MM/AAAA). Otros formatos de fecha no se detectan por
+  semantic_type salvo que `inferred_type` ya sea `"datetime"`.
+- `numeric_cols` se basa en `inferred_type == "numeric"` (no en "integer"/"float");
+  si tu profiler usa otra etiqueta, normalizala antes.
diff --git a/python/functions/datascience/detect_time_column.py b/python/functions/datascience/detect_time_column.py
new file mode 100644
index 00000000..aa817720
--- /dev/null
+++ b/python/functions/datascience/detect_time_column.py
@@ -0,0 +1,112 @@
+"""Detecta la columna temporal y las columnas numericas de un TableProfile (grupo eda).
+
+Funcion pura y determinista: a partir de la lista de columnas de un TableProfile
+producido por el grupo de capacidad `eda` (cada elemento es un ColumnProfile dict),
+decide cual es la columna de orden temporal y que columnas numericas hay disponibles
+para graficar una serie en el tiempo. Es la pieza que usa el capitulo TIMESERIES del
+AutomaticEDA para decidir si la tabla admite analisis de serie temporal.
+
+Lectura 100% defensiva al estilo "dict-no-throw" del grupo eda: nunca lanza
+excepcion, siempre devuelve el mismo conjunto de claves.
+"""
+
+# semantic_type que el profiler (infer_semantic_type) emite para fechas/datetimes.
+_DATETIME_SEMANTICS = ("datetime_iso", "date_eu")
+
+
+def detect_time_column(columns: list) -> dict:
+    """Detecta la columna temporal y las numericas de una lista de ColumnProfile.
+
+    Recorre los ColumnProfile de un TableProfile y clasifica cada columna como
+    temporal o numerica leyendo de forma defensiva sus claves. Una columna es
+    temporal si su ``inferred_type == "datetime"`` o si su ``semantic_type`` esta
+    en {``"datetime_iso"``, ``"date_eu"``}. La columna temporal elegida
+    (``time_col``) es la PRIMERA temporal en el orden de la lista. Las numericas
+    (``numeric_cols``) son las de ``inferred_type == "numeric"``, en orden.
+
+    Funcion pura: no hace I/O, no muta el input, es determinista.
+
+    Args:
+        columns: lista de ColumnProfile dict del grupo eda. Cada elemento suele
+            tener claves como ``name``, ``inferred_type``, ``semantic_type`` y
+            ``numeric``. Los elementos que no sean dict se ignoran. Si ``columns``
+            es None, no es lista o esta vacia, se devuelve el dict "no aplica".
+
+    Returns:
+        Siempre un dict con las mismas claves::
+
+            {
+              "time_col": str | None,     # columna temporal elegida (None si no hay)
+              "time_semantic": str,       # semantic_type de la temporal ("" si no aplica)
+              "numeric_cols": [str, ...], # columnas con inferred_type == "numeric"
+              "n_datetime_cols": int,     # nº de columnas temporales detectadas
+              "datetime_cols": [str, ...],# todas las temporales, en orden de aparicion
+              "reason": str,              # frase corta (en espanol) que explica la eleccion
+            }
+    """
+    # Caso "no aplica": entrada invalida o vacia.
+    if not isinstance(columns, list) or not columns:
+        return {
+            "time_col": None,
+            "time_semantic": "",
+            "numeric_cols": [],
+            "n_datetime_cols": 0,
+            "datetime_cols": [],
+            "reason": "no se detecto columna de fecha/datetime",
+        }
+
+    datetime_cols: list[str] = []
+    datetime_semantics: list[str] = []
+    numeric_cols: list[str] = []
+
+    for col in columns:
+        # Ignora elementos que no sean dict sin fallar.
+        if not isinstance(col, dict):
+            continue
+
+        name = col.get("name")
+        if name is None:
+            name = ""
+        else:
+            name = str(name)
+
+        inferred_type = col.get("inferred_type") or ""
+        semantic_type = col.get("semantic_type") or ""
+
+        is_datetime = inferred_type == "datetime" or semantic_type in _DATETIME_SEMANTICS
+        if is_datetime:
+            datetime_cols.append(name)
+            datetime_semantics.append(semantic_type)
+
+        if inferred_type == "numeric":
+            numeric_cols.append(name)
+
+    if not datetime_cols:
+        return {
+            "time_col": None,
+            "time_semantic": "",
+            "numeric_cols": numeric_cols,
+            "n_datetime_cols": 0,
+            "datetime_cols": [],
+            "reason": "no se detecto columna de fecha/datetime",
+        }
+
+    time_col = datetime_cols[0]
+    time_semantic = datetime_semantics[0]
+
+    if len(datetime_cols) == 1:
+        reason = f"columna temporal '{time_col}' detectada"
+    else:
+        reason = (
+            f"{len(datetime_cols)} columnas temporales; se elige la primera "
+            f"'{time_col}'"
+        )
+
+    return {
+        "time_col": time_col,
+        "time_semantic": time_semantic,
+        "numeric_cols": numeric_cols,
+        "n_datetime_cols": len(datetime_cols),
+        "datetime_cols": datetime_cols,
+        "reason": reason,
+    }
diff --git a/python/functions/datascience/detect_time_column_test.py b/python/functions/datascience/detect_time_column_test.py
new file mode 100644
index 00000000..0b391d2a
--- /dev/null
+++ b/python/functions/datascience/detect_time_column_test.py
@@ -0,0 +1,102 @@
+"""Tests para detect_time_column (grupo eda). Self-contained, sin DuckDB."""
+
+from detect_time_column import detect_time_column
+
+
+def test_golden_datetime_y_numericas():
+    columns = [
+        {"name": "fecha", "inferred_type": "datetime", "semantic_type": "datetime_iso"},
+        {"name": "ventas", "inferred_type": "numeric"},
+        {"name": "unidades", "inferred_type": "numeric"},
+        {"name": "region", "inferred_type": "text"},
+    ]
+    res = detect_time_column(columns)
+    assert res["time_col"] == "fecha"
+    assert res["time_semantic"] == "datetime_iso"
+    assert res["numeric_cols"] == ["ventas", "unidades"]
+    assert res["n_datetime_cols"] == 1
+    assert res["datetime_cols"] == ["fecha"]
+    assert isinstance(res["reason"], str) and res["reason"]
+
+
+def test_deteccion_por_semantic_type_date_eu():
+    # inferred_type no es datetime, pero semantic_type date_eu => temporal.
+    columns = [
+        {"name": "id", "inferred_type": "numeric"},
+        {"name": "dia", "inferred_type": "text", "semantic_type": "date_eu"},
+        {"name": "importe", "inferred_type": "numeric"},
+    ]
+    res = detect_time_column(columns)
+    assert res["time_col"] == "dia"
+    assert res["time_semantic"] == "date_eu"
+    assert res["numeric_cols"] == ["id", "importe"]
+    assert res["n_datetime_cols"] == 1
+    assert res["datetime_cols"] == ["dia"]
+
+
+def test_sin_columna_temporal():
+    columns = [
+        {"name": "id", "inferred_type": "numeric"},
+        {"name": "nombre", "inferred_type": "text"},
+        {"name": "activo", "inferred_type": "boolean"},
+    ]
+    res = detect_time_column(columns)
+    assert res["time_col"] is None
+    assert res["time_semantic"] == ""
+    assert res["numeric_cols"] == ["id"]
+    assert res["n_datetime_cols"] == 0
+    assert res["datetime_cols"] == []
+    assert res["reason"] == "no se detecto columna de fecha/datetime"
+
+
+def test_columns_none_no_revienta():
+    res = detect_time_column(None)
+    assert res["time_col"] is None
+    assert res["time_semantic"] == ""
+    assert res["numeric_cols"] == []
+    assert res["n_datetime_cols"] == 0
+    assert res["datetime_cols"] == []
+    assert res["reason"] == "no se detecto columna de fecha/datetime"
+
+
+def test_columns_vacia_no_revienta():
+    res = detect_time_column([])
+    assert res["time_col"] is None
+    assert res["numeric_cols"] == []
+    assert res["n_datetime_cols"] == 0
+
+
+def test_columns_no_lista_no_revienta():
+    # Un dict (no lista) tambien debe caer en el caso "no aplica".
+    res = detect_time_column({"name": "fecha", "inferred_type": "datetime"})
+    assert res["time_col"] is None
+    assert res["numeric_cols"] == []
+
+
+def test_elementos_basura_se_ignoran():
+    columns = [
+        None,
+        "no soy un dict",
+        42,
+        {"name": "ts", "inferred_type": "datetime"},
+        {"name": "valor", "inferred_type": "numeric"},
+    ]
+    res = detect_time_column(columns)
+    assert res["time_col"] == "ts"
+    assert res["numeric_cols"] == ["valor"]
+    assert res["n_datetime_cols"] == 1
+
+
+def test_varias_datetime_elige_la_primera():
+    columns = [
+        {"name": "created_at", "inferred_type": "datetime", "semantic_type": "datetime_iso"},
+        {"name": "metric", "inferred_type": "numeric"},
+        {"name": "updated_at", "inferred_type": "datetime", "semantic_type": "datetime_iso"},
+        {"name": "fecha_baja", "inferred_type": "text", "semantic_type": "date_eu"},
+    ]
+    res = detect_time_column(columns)
+    assert res["time_col"] == "created_at"
+    assert res["time_semantic"] == "datetime_iso"
+    assert res["n_datetime_cols"] == 3
+    assert res["datetime_cols"] == ["created_at", "updated_at", "fecha_baja"]
+    assert res["numeric_cols"] == ["metric"]
diff --git a/python/functions/datascience/extract_timeseries_raw.md b/python/functions/datascience/extract_timeseries_raw.md
new file mode 100644
index 00000000..5ce92f91
--- /dev/null
+++ b/python/functions/datascience/extract_timeseries_raw.md
@@ -0,0 +1,92 @@
+---
+name: extract_timeseries_raw
+kind: function
+lang: py
+domain: datascience
+version: "1.0.0"
+purity: impure
+signature: "def extract_timeseries_raw(query_fn, table: str, time_col: str, value_cols: list, max_rows: int = 5000) -> dict"
+description: "Extrae la serie temporal CRUDA (fechas + una o varias columnas numericas) de una tabla, ordenada cronologicamente, para alimentar el render del capitulo TIMESERIES de AutomaticEDA (linea valor-vs-tiempo + conteo por periodo). 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 con identificadores escapados, ORDER BY por la columna temporal y LIMIT. Devuelve dict dict-no-throw: t (fechas ISO string), series (lista paralela float|None por columna) y n. El capitulo no toca la BD: recibe esto en ctx['timeseries_raw']. Reutilizable tambien por profile_table en una fase futura."
+tags: [eda, timeseries, datascience, automatic-eda, extraction, read-only, duckdb, postgres, python]
+uses_functions: []
+uses_types: []
+returns: []
+returns_optional: false
+error_type: "error_go_core"
+imports: [datetime]
+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 extraer la serie. Se escapa con comillas dobles en la query."
+  - name: time_col
+    desc: "nombre de la columna de orden temporal. Se usa en ORDER BY (cronologico ascendente) y se filtra IS NOT NULL. Sus valores se devuelven en `t` como string ISO."
+  - name: value_cols
+    desc: "lista de nombres de columnas numericas a extraer. Cada una produce una entrada en `series` con una lista paralela a `t`. Vacia o None -> status error."
+  - name: max_rows
+    desc: "limite de filas a leer (clausula LIMIT). Default 5000. Protege el render frente a tablas enormes."
+output: "dict (nunca lanza). En exito: {'status':'ok','time_col':str,'t':[str,...] (fechas ISO en orden),'series':{col:[float|None,...],...} (paralela a t por value_col, None si el valor no es convertible a float),'n':int}. En error (sin lanzar): {'status':'error','error':str,'time_col':str,'t':[],'series':{},'n':0}. Errores: query_fn None, value_cols vacia, table/time_col vacios, o query_fn devuelve status!='ok' (se propaga su error)."
+tested: true
+tests: ["test_golden_t_y_series_alineadas", "test_valor_no_convertible_da_none", "test_value_cols_vacia_status_error", "test_query_fn_status_error_propaga", "test_query_fn_none_da_error_sin_reventar", "test_sql_contiene_order_by_y_limit"]
+test_file_path: "python/functions/datascience/extract_timeseries_raw_test.py"
+file_path: "python/functions/datascience/extract_timeseries_raw.py"
+---
+
+## Ejemplo
+
+```python
+import sys, os
+sys.path.insert(0, os.path.join("python", "functions"))
+from datascience import extract_timeseries_raw
+from infra import duckdb_query_readonly
+
+# El lector read-only se inyecta como closure (igual que el `_q` de profile_table).
+db = "data/ventas.duckdb"
+def _q(sql):
+    return duckdb_query_readonly(db, sql)
+
+res = extract_timeseries_raw(_q, "ventas_diarias", "fecha", ["importe", "unidades"])
+# res == {
+#   "status": "ok",
+#   "time_col": "fecha",
+#   "t": ["2024-01-01", "2024-01-02", ...],
+#   "series": {"importe": [1234.5, 980.0, ...], "unidades": [12.0, 9.0, ...]},
+#   "n": 365,
+# }
+
+# Se entrega al capitulo TIMESERIES sin que este toque la BD:
+ctx = {"timeseries_raw": res}
+```
+
+## Cuando usarla
+
+Cuando el capitulo TIMESERIES de AutomaticEDA necesita pintar una serie
+valor-vs-tiempo (o conteo por periodo) y NO debe abrir la base de datos por su
+cuenta: extraes aqui las fechas + columnas numericas ordenadas y se las pasas en
+`ctx['timeseries_raw']`. Usala tambien siempre que quieras la secuencia cruda
+ordenada cronologicamente de una o varias columnas para alimentar otros
+contrastes de serie (ADF/KPSS, ACF/PACF, STL) reutilizando un unico lector
+read-only inyectado, en vez de hacer N muestreos a mano.
+
+## 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 `t=[]`, `series={}`, `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.
+- **No loguear los datos crudos**: `t`/`series` pueden contener datos sensibles
+  (igual que un HAR). No volcar el dict completo a logs ni a telemetria; en
+  trazas usa solo `n` y los nombres de columna.
+- **Alineacion por fila**: `series[col][i]` corresponde a `t[i]`. Un valor no
+  convertible a float se guarda como `None` (no se descarta la fila) para no
+  romper la alineacion temporal.
+- **Orden**: el orden cronologico depende del `ORDER BY "time_col"` del backend.
+  Si `time_col` esta guardada como texto con formato no lexicograficamente
+  ordenable (p.ej. `DD/MM/YYYY`), el orden no sera el real — normaliza la columna
+  a date/timestamp antes, o pasa una columna ya ordenable.
+- **`max_rows`**: con LIMIT, si la tabla supera `max_rows` obtienes solo el primer
+  tramo cronologico, no un muestreo uniforme. Sube `max_rows` si necesitas el rango
+  completo.
diff --git a/python/functions/datascience/extract_timeseries_raw.py b/python/functions/datascience/extract_timeseries_raw.py
new file mode 100644
index 00000000..455c90f4
--- /dev/null
+++ b/python/functions/datascience/extract_timeseries_raw.py
@@ -0,0 +1,122 @@
+"""extract_timeseries_raw — extrae la serie temporal CRUDA 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 ordenada
+por la columna temporal y devuelve las fechas (`t`) mas cada columna numerica en
+listas paralelas (`series`), listas para alimentar el render del capitulo
+TIMESERIES de AutomaticEDA (linea valor-vs-tiempo + conteo por periodo) sin que
+el capitulo toque la base de datos: recibe esto en `ctx['timeseries_raw']`.
+
+Estilo dict-no-throw del grupo `eda`: nunca lanza; captura cualquier excepcion y
+degrada a `{"status": "error", "error": str, ...}`.
+"""
+
+from datetime import date, datetime
+
+
+def _to_float(value):
+    """Convierte un valor a float de forma defensiva. None si no es convertible."""
+    if value is None:
+        return None
+    if isinstance(value, bool):
+        # Un bool es subclase de int en Python; no es un valor de serie valido.
+        return None
+    if isinstance(value, (int, float)):
+        return float(value)
+    s = str(value).strip()
+    if not s:
+        return None
+    try:
+        return float(s)
+    except (TypeError, ValueError):
+        return None
+
+
+def _to_iso(value):
+    """Convierte un valor temporal a string ISO conservando el orden de la query.
+
+    date/datetime -> isoformat(); cualquier otro valor (string, etc.) -> str().
+    None se preserva como None.
+    """
+    if value is None:
+        return None
+    if isinstance(value, (datetime, date)):
+        return value.isoformat()
+    return str(value)
+
+
+def extract_timeseries_raw(query_fn, table, time_col, value_cols, max_rows=5000):
+    """Extrae la serie temporal cruda (fechas + columnas numericas) de una 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.
+        time_col: nombre de la columna de orden temporal.
+        value_cols: lista de nombres de columnas numericas a extraer.
+        max_rows: limite de filas (LIMIT). Default 5000.
+
+    Returns:
+        dict (nunca lanza):
+            {
+              "status": "ok" | "error",
+              "error": str,                 # solo si status == "error"
+              "time_col": str,
+              "t": [str, ...],              # time_col como ISO string, en orden
+              "series": {col: [float|None, ...], ...},  # paralela a t por columna
+              "n": int                      # nº de filas devueltas
+            }
+    """
+    base = {"status": "ok", "time_col": time_col, "t": [], "series": {}, "n": 0}
+    try:
+        if query_fn is None:
+            return {**base, "status": "error", "error": "query_fn es None"}
+        if not value_cols:
+            return {**base, "status": "error", "error": "value_cols vacío"}
+        if not table or not time_col:
+            return {
+                **base,
+                "status": "error",
+                "error": "table y time_col son obligatorios",
+            }
+
+        # Identificadores escapados con comillas dobles (como hace profile_table)
+        # para tolerar nombres con mayusculas/espacios/palabras reservadas.
+        cols_sql = ", ".join(f'"{c}"' for c in value_cols)
+        sql = (
+            f'SELECT "{time_col}", {cols_sql} FROM "{table}" '
+            f'WHERE "{time_col}" IS NOT NULL '
+            f'ORDER BY "{time_col}" '
+            f"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 []
+        t = []
+        series = {c: [] for c in value_cols}
+        for row in rows:
+            t.append(_to_iso(row.get(time_col)))
+            for c in value_cols:
+                series[c].append(_to_float(row.get(c)))
+
+        return {
+            "status": "ok",
+            "time_col": time_col,
+            "t": t,
+            "series": series,
+            "n": len(t),
+        }
+    except Exception as e:  # noqa: BLE001 - dict-no-throw: degradar, nunca lanzar
+        return {**base, "status": "error", "error": str(e)}
diff --git a/python/functions/datascience/extract_timeseries_raw_test.py b/python/functions/datascience/extract_timeseries_raw_test.py
new file mode 100644
index 00000000..bcfd1bd5
--- /dev/null
+++ b/python/functions/datascience/extract_timeseries_raw_test.py
@@ -0,0 +1,109 @@
+"""Tests para extract_timeseries_raw.
+
+No usa DuckDB real: inyecta un query_fn FAKE (closure) que devuelve filas
+predefinidas y, opcionalmente, captura el SQL recibido para verificar la query
+generada (ORDER BY por la columna temporal + 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_timeseries_raw import extract_timeseries_raw
+
+
+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_t_y_series_alineadas():
+    """Golden: t y series alineadas, floats convertidos, n correcto."""
+    rows = [
+        {"fecha": "2024-01-01", "ventas": "10", "stock": 5},
+        {"fecha": "2024-01-02", "ventas": "20.5", "stock": 7},
+        {"fecha": "2024-01-03", "ventas": 30, "stock": 9},
+    ]
+    res = extract_timeseries_raw(_fake_query(rows), "t", "fecha", ["ventas", "stock"])
+    assert res["status"] == "ok"
+    assert res["n"] == 3
+    assert res["time_col"] == "fecha"
+    assert res["t"] == ["2024-01-01", "2024-01-02", "2024-01-03"]
+    assert res["series"]["ventas"] == [10.0, 20.5, 30.0]
+    assert res["series"]["stock"] == [5.0, 7.0, 9.0]
+
+
+def test_valor_no_convertible_da_none():
+    """Valor no convertible a float -> None en la serie (alineacion preservada)."""
+    rows = [
+        {"fecha": "2024-01-01", "ventas": "abc"},
+        {"fecha": "2024-01-02", "ventas": None},
+        {"fecha": "2024-01-03", "ventas": "12.5"},
+    ]
+    res = extract_timeseries_raw(_fake_query(rows), "t", "fecha", ["ventas"])
+    assert res["status"] == "ok"
+    assert res["series"]["ventas"] == [None, None, 12.5]
+    assert res["n"] == 3
+
+
+def test_value_cols_vacia_status_error():
+    """value_cols vacia -> status error con t/series/n vacios."""
+    res = extract_timeseries_raw(_fake_query([]), "t", "fecha", [])
+    assert res["status"] == "error"
+    assert "value_cols" in res["error"]
+    assert res["t"] == []
+    assert res["series"] == {}
+    assert res["n"] == 0
+
+
+def test_query_fn_status_error_propaga():
+    """query_fn que devuelve status != ok -> se propaga como error."""
+    res = extract_timeseries_raw(
+        _fake_query([], status="error", error="db locked"),
+        "t",
+        "fecha",
+        ["ventas"],
+    )
+    assert res["status"] == "error"
+    assert "db locked" in res["error"]
+    assert res["n"] == 0
+
+
+def test_query_fn_none_da_error_sin_reventar():
+    """query_fn None -> error degradado, sin excepcion."""
+    res = extract_timeseries_raw(None, "t", "fecha", ["ventas"])
+    assert res["status"] == "error"
+    assert res["t"] == []
+    assert res["n"] == 0
+
+
+def test_sql_contiene_order_by_y_limit():
+    """La query generada ordena por time_col y aplica el LIMIT sobre la tabla."""
+    captured = []
+    rows = [{"fecha": "2024-01-01", "ventas": 1}]
+    extract_timeseries_raw(
+        _fake_query(rows, captured),
+        "ventas_tbl",
+        "fecha",
+        ["ventas"],
+        max_rows=123,
+    )
+    assert len(captured) == 1
+    sql = captured[0]
+    assert 'ORDER BY "fecha"' in sql
+    assert "LIMIT 123" in sql
+    assert 'FROM "ventas_tbl"' in sql
diff --git a/python/functions/datascience/profile_datetime.md b/python/functions/datascience/profile_datetime.md
new file mode 100644
index 00000000..0f0ced85
--- /dev/null
+++ b/python/functions/datascience/profile_datetime.md
@@ -0,0 +1,79 @@
+---
+name: profile_datetime
+kind: function
+lang: py
+domain: datascience
+version: "1.0.0"
+purity: pure
+signature: "def profile_datetime(values: list) -> dict"
+description: "Perfil minimo de una columna fecha/datetime para la cabecera del capitulo TIMESERIES de AutomaticEDA. Acepta datetime.date, datetime.datetime y strings ISO mezclados, parsea defensivamente e ignora lo no parseable (nunca lanza). Devuelve rango (min/max ISO), n, n_distinct, span_days, frecuencia inferida (daily/weekly/monthly/quarterly/yearly/irregular/unknown) a partir del paso mediano entre fechas distintas, is_regular (pasos ~constantes), n_gaps (huecos en la rejilla) y median_step_days. Solo stdlib (datetime + statistics)."
+tags: [statistics, timeseries, datetime, profiling, frequency, eda, automatic_eda, python]
+uses_functions: []
+uses_types: []
+returns: []
+returns_optional: false
+error_type: ""
+imports: [datetime, statistics]
+params:
+  - name: values
+    desc: "lista de valores fecha. Acepta datetime.date, datetime.datetime y strings ISO ('2021-06-28', '2021-06-28T00:00:00', '2021-06-28 12:00:00'). None, vacios y no parseables se ignoran; tz-aware se normaliza a naive. Si values es None o no iterable se trata como lista vacia."
+output: "dict SIEMPRE presente con: 'min'/'max' (ISO date YYYY-MM-DD o None), 'n' (valores parseables), 'n_distinct' (fechas unicas), 'span_days' (float o None), 'freq' (daily|weekly|monthly|quarterly|yearly|irregular|unknown), 'is_regular' (bool), 'n_gaps' (int), 'median_step_days' (float o None) y 'note' (str). Con <2 valores o una sola fecha distinta: freq='unknown', is_regular=False, n_gaps=0, median_step_days=None y nota. Nunca lanza."
+tested: true
+tests: ["test_serie_diaria_regular_golden", "test_serie_mensual_freq_monthly", "test_serie_con_hueco_cuenta_gaps", "test_strings_iso_mezclados_con_datetime", "test_lista_vacia_y_none_devuelve_unknown", "test_valores_no_parseables_ignorados", "test_span_days_correcto", "test_una_sola_fecha_es_coherente"]
+test_file_path: "python/functions/datascience/profile_datetime_test.py"
+file_path: "python/functions/datascience/profile_datetime.py"
+---
+
+## Ejemplo
+
+```python
+from datascience import profile_datetime
+from datetime import date, datetime, timedelta
+
+# Serie diaria regular de 30 dias
+fechas = [date(2021, 1, 1) + timedelta(days=i) for i in range(30)]
+res = profile_datetime(fechas)
+res["freq"]              # -> "daily"
+res["is_regular"]        # -> True
+res["n_gaps"]            # -> 0
+res["min"], res["max"]   # -> ("2021-01-01", "2021-01-30")
+res["span_days"]         # -> 29.0
+
+# Acepta strings ISO mezclados con objetos datetime/date; ignora lo no parseable
+profile_datetime(["2021-06-28", datetime(2021, 6, 29, 12), "basura", None])["n"]   # -> 2
+
+# Columna vacia o sin fechas validas
+profile_datetime([])["freq"]   # -> "unknown" + note "datos insuficientes"
+```
+
+## Cuando usarla
+
+Cuando construyes la cabecera del capitulo TIMESERIES de un EDA y necesitas
+caracterizar la columna de fecha antes de modelar: que rango cubre, cada cuanto
+llegan los datos (frecuencia), si la cadencia es regular y si hay huecos en la
+rejilla temporal. Es el complemento de fecha al perfil numerico/categorico del
+TableProfile (cierra el `datetime{}=None` pendiente). Pasale la columna de fechas
+en bruto (tal cual venga de la BD: dates, datetimes o strings ISO) y usa `freq` +
+`is_regular` + `n_gaps` para decidir si conviene resamplear, rellenar huecos o
+desestacionalizar mas adelante.
+
+## Gotchas
+
+- Es pura y stdlib-only, pero la inferencia de `freq` es heuristica por bandas
+  sobre el **paso mediano entre fechas distintas** (se deduplica antes de medir).
+  Cualquier paso fuera de las bandas conocidas (incluido sub-diario, p.ej. datos
+  horarios) cae en `"irregular"`: no hay banda hourly.
+- El analisis de frecuencia/regularidad/huecos necesita **>=2 fechas distintas**.
+  Con 0-1 valores parseables o una sola fecha unica, `freq="unknown"`,
+  `median_step_days=None` y `n_gaps=0`, pero `min`/`max`/`span_days` siguen siendo
+  coherentes si hay al menos una fecha.
+- `min`/`max` se reportan como ISO **date** (`YYYY-MM-DD`); la hora se conserva
+  internamente para calcular `span_days` y `median_step_days` (que pueden ser
+  fraccionarios con datetimes sub-diarios) pero no aparece en min/max.
+- Los datetime con zona horaria se normalizan a naive (se descarta el tzinfo) para
+  poder mezclarlos con fechas naive sin que las restas lancen; esto puede desplazar
+  la fecha en datetimes con offset grande. Para EDA es despreciable.
+- `is_regular` usa tolerancia ±25% sobre el paso mediano y umbral del 80% de los
+  pasos dentro de banda; series de "primero de mes" (deltas 28-31) salen regulares.
+- `n_gaps` solo se calcula cuando `freq` es una rejilla regular conocida; con
+  `freq` `"irregular"` o `"unknown"` siempre es 0.
diff --git a/python/functions/datascience/profile_datetime.py b/python/functions/datascience/profile_datetime.py
new file mode 100644
index 00000000..15c21ffa
--- /dev/null
+++ b/python/functions/datascience/profile_datetime.py
@@ -0,0 +1,183 @@
+"""Perfil minimo de una columna fecha/datetime para la cabecera TIMESERIES (grupo eda).
+
+Funcion pura y determinista que resume una columna temporal: rango (min/max),
+numero de fechas distintas, frecuencia inferida (daily/weekly/monthly/quarterly/
+yearly/irregular), regularidad de los pasos, huecos respecto a la rejilla inferida
+y paso mediano entre fechas consecutivas. Cierra el `datetime{}=None` que hoy deja
+pendiente el TableProfile de AutomaticEDA.
+
+Acepta valores heterogeneos (``datetime.date``, ``datetime.datetime`` y strings
+ISO como ``"2021-06-28"``, ``"2021-06-28T00:00:00"`` o ``"2021-06-28 12:00:00"``),
+parsea de forma defensiva, ignora lo que no se puede parsear y NUNCA lanza.
+
+Solo usa stdlib (``datetime`` + ``statistics``).
+"""
+
+from __future__ import annotations
+
+import statistics
+from datetime import date, datetime
+
+
+def _parse_one(v) -> datetime | None:
+    """Parsea un valor a ``datetime`` naive, o devuelve None si no es una fecha.
+
+    Acepta ``datetime.datetime``, ``datetime.date`` y strings ISO. Cualquier
+    datetime con zona horaria se normaliza a naive (se descarta el tzinfo) para
+    poder mezclarlo con fechas naive sin que las restas lancen ``TypeError``.
+    """
+    if v is None or isinstance(v, bool):
+        return None
+    # datetime es subclase de date: comprobar datetime primero.
+    if isinstance(v, datetime):
+        return v.replace(tzinfo=None)
+    if isinstance(v, date):
+        return datetime(v.year, v.month, v.day)
+    if isinstance(v, str):
+        s = v.strip()
+        if not s:
+            return None
+        try:
+            dt = datetime.fromisoformat(s)
+        except ValueError:
+            return None
+        return dt.replace(tzinfo=None)
+    return None
+
+
+def _infer_freq(median_step_days: float) -> str:
+    """Clasifica la frecuencia a partir del paso mediano (en dias) entre fechas.
+
+    Bandas con tolerancia: ~1 dia -> daily, ~7 -> weekly, 28-31 -> monthly,
+    89-92 -> quarterly, 360-366 -> yearly. Cualquier paso fuera de las bandas
+    (incluido sub-diario) -> irregular.
+    """
+    m = median_step_days
+    if 0.5 <= m <= 1.5:
+        return "daily"
+    if 6.0 <= m <= 8.0:
+        return "weekly"
+    if 28.0 <= m <= 31.0:
+        return "monthly"
+    if 89.0 <= m <= 92.0:
+        return "quarterly"
+    if 360.0 <= m <= 366.0:
+        return "yearly"
+    return "irregular"
+
+
+def profile_datetime(values: list) -> dict:
+    """Perfila una columna de fechas para la cabecera del capitulo TIMESERIES.
+
+    Funcion pura y determinista: no hace I/O, no muta el input y nunca lanza.
+
+    El analisis de frecuencia, regularidad y huecos se hace sobre las **fechas
+    distintas ordenadas** (se deduplica antes de calcular los pasos): los valores
+    repetidos generarian pasos de 0 dias que distorsionarian el mediano y la
+    inferencia. ``n`` cuenta los valores parseables (con duplicados) y
+    ``n_distinct`` las fechas unicas.
+
+    Args:
+        values: lista de valores fecha. Acepta ``datetime.date``,
+            ``datetime.datetime`` y strings ISO (``"2021-06-28"``,
+            ``"2021-06-28T00:00:00"``, ``"2021-06-28 12:00:00"``). Los valores
+            None, vacios o no parseables se ignoran. Si ``values`` es None o no
+            iterable se trata como lista vacia.
+
+    Returns:
+        Siempre un dict con esta forma::
+
+            {
+              "min": str | None,             # fecha minima ISO date (YYYY-MM-DD)
+              "max": str | None,             # fecha maxima ISO date
+              "n": int,                      # nº de valores fecha parseables
+              "n_distinct": int,             # nº de fechas distintas
+              "span_days": float | None,     # (max - min) en dias
+              "freq": str,                   # daily|weekly|monthly|quarterly|
+                                             #   yearly|irregular|unknown
+              "is_regular": bool,            # pasos ~constantes (tolerancia ±25%)
+              "n_gaps": int,                 # saltos > ~1.5x el paso mediano
+              "median_step_days": float | None,  # paso mediano entre fechas
+              "note": str                    # "" o nota corta
+            }
+
+        Con menos de 2 valores parseables (o una sola fecha distinta) devuelve
+        ``freq="unknown"``, ``is_regular=False``, ``n_gaps=0``,
+        ``median_step_days=None`` y la nota correspondiente, manteniendo min/max
+        y span_days coherentes cuando hay al menos una fecha.
+    """
+    base = {
+        "min": None,
+        "max": None,
+        "n": 0,
+        "n_distinct": 0,
+        "span_days": None,
+        "freq": "unknown",
+        "is_regular": False,
+        "n_gaps": 0,
+        "median_step_days": None,
+        "note": "",
+    }
+
+    if values is None:
+        values = []
+    try:
+        iterator = list(values)
+    except TypeError:
+        iterator = []
+
+    parsed: list[datetime] = []
+    for v in iterator:
+        dt = _parse_one(v)
+        if dt is not None:
+            parsed.append(dt)
+
+    n = len(parsed)
+    base["n"] = n
+
+    if n == 0:
+        base["note"] = "datos insuficientes"
+        return base
+
+    distinct = sorted(set(parsed))
+    n_distinct = len(distinct)
+    dt_min = min(parsed)
+    dt_max = max(parsed)
+
+    base["n_distinct"] = n_distinct
+    base["min"] = dt_min.date().isoformat()
+    base["max"] = dt_max.date().isoformat()
+    base["span_days"] = round((dt_max - dt_min).total_seconds() / 86400.0, 6)
+
+    # Sin al menos dos fechas distintas no hay pasos que medir.
+    if n_distinct < 2:
+        base["note"] = "datos insuficientes" if n < 2 else "una sola fecha distinta"
+        return base
+
+    steps = [
+        (distinct[i + 1] - distinct[i]).total_seconds() / 86400.0
+        for i in range(n_distinct - 1)
+    ]
+    median_step = float(statistics.median(steps))
+    base["median_step_days"] = round(median_step, 6)
+
+    freq = _infer_freq(median_step)
+    base["freq"] = freq
+
+    # Regularidad: >=80% de los pasos dentro de ±25% del paso mediano.
+    if median_step > 0:
+        tol = 0.25 * median_step
+        within = sum(1 for s in steps if abs(s - median_step) <= tol)
+        base["is_regular"] = (within / len(steps)) >= 0.8
+    else:
+        base["is_regular"] = False
+
+    # Huecos: pasos que superan ~1.5x el mediano. Solo tiene sentido cuando la
+    # frecuencia es una rejilla regular conocida (no irregular/unknown).
+    if freq not in ("unknown", "irregular") and median_step > 0:
+        threshold = 1.5 * median_step
+        base["n_gaps"] = sum(1 for s in steps if s > threshold)
+    else:
+        base["n_gaps"] = 0
+
+    return base
diff --git a/python/functions/datascience/profile_datetime_test.py b/python/functions/datascience/profile_datetime_test.py
new file mode 100644
index 00000000..533f701d
--- /dev/null
+++ b/python/functions/datascience/profile_datetime_test.py
@@ -0,0 +1,127 @@
+"""Tests para profile_datetime."""
+
+from datetime import date, datetime, timedelta
+
+from profile_datetime import profile_datetime
+
+
+def test_serie_diaria_regular_golden():
+    # 30 dias consecutivos: frecuencia diaria, regular, sin huecos.
+    fechas = [date(2021, 1, 1) + timedelta(days=i) for i in range(30)]
+    res = profile_datetime(fechas)
+    assert res["n"] == 30
+    assert res["n_distinct"] == 30
+    assert res["min"] == "2021-01-01"
+    assert res["max"] == "2021-01-30"
+    assert res["span_days"] == 29.0
+    assert res["freq"] == "daily"
+    assert res["is_regular"] is True
+    assert res["n_gaps"] == 0
+    assert res["median_step_days"] == 1.0
+    assert res["note"] == ""
+
+
+def test_serie_mensual_freq_monthly():
+    # Primero de mes durante 14 meses: paso mediano ~30/31 dias -> monthly.
+    fechas = []
+    y, m = 2021, 1
+    for _ in range(14):
+        fechas.append(date(y, m, 1))
+        m += 1
+        if m > 12:
+            m = 1
+            y += 1
+    res = profile_datetime(fechas)
+    assert res["n"] == 14
+    assert res["freq"] == "monthly"
+    assert res["min"] == "2021-01-01"
+    assert res["max"] == "2022-02-01"
+    assert 28.0 <= res["median_step_days"] <= 31.0
+
+
+def test_serie_con_hueco_cuenta_gaps():
+    # Serie diaria con un hueco de 3 dias (faltan i=7,8,9) -> n_gaps >= 1.
+    fechas = [
+        date(2021, 1, 1) + timedelta(days=i)
+        for i in range(20)
+        if i not in (7, 8, 9)
+    ]
+    res = profile_datetime(fechas)
+    assert res["freq"] == "daily"
+    assert res["n_gaps"] >= 1
+    assert res["median_step_days"] == 1.0
+
+
+def test_strings_iso_mezclados_con_datetime():
+    # Mezcla de strings ISO (varios formatos) y objetos datetime/date.
+    valores = [
+        "2021-06-28",
+        datetime(2021, 6, 29, 12, 0, 0),
+        "2021-06-30T00:00:00",
+        date(2021, 7, 1),
+    ]
+    res = profile_datetime(valores)
+    assert res["n"] == 4
+    assert res["n_distinct"] == 4
+    assert res["min"] == "2021-06-28"
+    assert res["max"] == "2021-07-01"
+    assert res["freq"] == "daily"
+    assert res["note"] == ""
+
+
+def test_lista_vacia_y_none_devuelve_unknown():
+    for entrada in ([], None):
+        res = profile_datetime(entrada)
+        assert res["n"] == 0
+        assert res["n_distinct"] == 0
+        assert res["min"] is None
+        assert res["max"] is None
+        assert res["span_days"] is None
+        assert res["freq"] == "unknown"
+        assert res["is_regular"] is False
+        assert res["n_gaps"] == 0
+        assert res["median_step_days"] is None
+        assert res["note"] == "datos insuficientes"
+
+
+def test_valores_no_parseables_ignorados():
+    # Strings basura, None, ints y un date valido mezclados: ignora lo no fecha.
+    valores = [
+        "no es una fecha",
+        None,
+        "2021-01-01",
+        "2021-01-02",
+        12345,
+        "tampoco",
+        date(2021, 1, 3),
+        "",
+    ]
+    res = profile_datetime(valores)
+    assert res["n"] == 3  # solo 3 fechas parseables
+    assert res["n_distinct"] == 3
+    assert res["freq"] == "daily"
+    assert res["min"] == "2021-01-01"
+    assert res["max"] == "2021-01-03"
+
+
+def test_span_days_correcto():
+    # Dos fechas a un anio de distancia: span 365 dias -> yearly.
+    res = profile_datetime([date(2020, 1, 1), date(2020, 12, 31)])
+    assert res["n"] == 2
+    assert res["n_distinct"] == 2
+    assert res["span_days"] == 365.0
+    assert res["median_step_days"] == 365.0
+    assert res["freq"] == "yearly"
+
+
+def test_una_sola_fecha_es_coherente():
+    # Un unico valor: min == max, span 0, freq unknown, nota datos insuficientes.
+    res = profile_datetime(["2021-06-28"])
+    assert res["n"] == 1
+    assert res["n_distinct"] == 1
+    assert res["min"] == "2021-06-28"
+    assert res["max"] == "2021-06-28"
+    assert res["span_days"] == 0.0
+    assert res["freq"] == "unknown"
+    assert res["median_step_days"] is None
+    assert res["note"] == "datos insuficientes"
diff --git a/python/functions/datascience/resample_timeseries.md b/python/functions/datascience/resample_timeseries.md
new file mode 100644
index 00000000..554920d2
--- /dev/null
+++ b/python/functions/datascience/resample_timeseries.md
@@ -0,0 +1,72 @@
+---
+name: resample_timeseries
+kind: function
+lang: py
+domain: datascience
+version: "1.0.0"
+purity: pure
+signature: "def resample_timeseries(t: list, v: list, freq: str = \"auto\", agg: str = \"mean\", max_points: int = 400) -> dict"
+description: "Agrega una serie temporal por periodo para graficar su evolucion y el CONTEO de observaciones por bucket. Nucleo del capitulo TIMESERIES de AutomaticEDA (grupo eda): recibe las fechas y los valores YA leidos (pura, sin tocar ninguna base de datos), empareja t[i] con v[i] por indice, parsea fechas defensivamente, trunca cada fecha al inicio de su bucket (daily/weekly/monthly/quarterly/yearly), y agrega los valores numericos validos por bucket mientras cuenta TODAS las observaciones con fecha valida (densidad temporal, incluida la fila cuyo valor es None). freq='auto' infiere del delta mediano entre fechas. Si hay mas buckets que max_points hace downsampling uniforme conservando primero y ultimo. Estilo dict-no-throw: NUNCA lanza; entrada vacia o longitudes incompatibles devuelve listas vacias + note='datos insuficientes'."
+tags: [eda, timeseries, resample, aggregate, profiling, datascience, time]
+params:
+  - name: t
+    desc: "Lista de fechas paralela a v. Acepta strings ISO ('YYYY-MM-DD' o 'YYYY-MM-DDTHH:MM:SS', con 'Z' opcional), datetime.date o datetime.datetime. Se parsea defensivamente; los pares cuya fecha no parsea se descartan junto con su valor."
+  - name: v
+    desc: "Lista de valores numericos (float/int) paralela a t. Puede contener None o valores no numericos: se ignoran en la agregacion pero la fila sigue contando en 'count' si su fecha es valida. bool, NaN e Inf se tratan como no numericos."
+  - name: freq
+    desc: "Granularidad del bucket: 'auto' (infiere del delta mediano en dias entre fechas: <=3 daily, <=16 weekly, <=75 monthly, <=200 quarterly, mayor yearly) o explicita en {daily, weekly, monthly, quarterly, yearly}. Una frecuencia desconocida cae a 'auto'."
+  - name: agg
+    desc: "Agregacion por bucket sobre los valores numericos validos: 'mean' | 'sum' | 'median' | 'last' (valor de la observacion cronologicamente mas reciente del bucket) | 'min' | 'max'. Una agregacion desconocida cae a 'mean'."
+  - name: max_points
+    desc: "Tope de buckets en la salida. Si n_buckets > max_points hace downsampling uniforme (1 de cada k buckets equiespaciados, conservando el primero y el ultimo) para no saturar el grafico del PDF/PPTX. max_points<=0 desactiva el limite."
+output: "Dict siempre con las mismas claves: t (lista de etiquetas ISO 'YYYY-MM-DD' por bucket, orden cronologico), v (lista paralela del valor agregado por bucket segun agg; None si el bucket no tiene ningun valor numerico valido), count (lista paralela del nº de observaciones con fecha valida por bucket), freq (frecuencia efectivamente usada), agg (agregacion usada), n_in (nº de pares (t,v) con fecha valida que entraron), n_buckets (nº de buckets antes del downsample), downsampled (bool, True si se aplico downsampling), note ('' o 'datos insuficientes' cuando no hay pares validos / longitudes incompatibles / listas vacias). Numericos de v en float, count en int."
+uses_functions: []
+uses_types: []
+returns: []
+returns_optional: false
+error_type: ""
+imports: []
+tested: true
+tests: ["test_daily_a_mensual_mean", "test_agg_sum_y_last", "test_count_cuenta_observacion_con_valor_none", "test_downsampling_respeta_max_points_y_extremos", "test_freq_auto_infiere_mensual", "test_edge_listas_vacias_o_desiguales"]
+test_file_path: "python/functions/datascience/resample_timeseries_test.py"
+file_path: "python/functions/datascience/resample_timeseries.py"
+---
+
+## Ejemplo
+
+```python
+import sys, os
+sys.path.insert(0, os.path.join("python", "functions"))
+from datascience.resample_timeseries import resample_timeseries
+
+# Serie diaria agregada a buckets mensuales: media del valor + conteo de filas.
+t = ["2020-01-01", "2020-01-15", "2020-02-01", "2020-02-10", "2020-02-20"]
+v = [10.0, 20.0, 30.0, 40.0, 50.0]
+
+r = resample_timeseries(t, v, freq="monthly", agg="mean")
+print(r["t"])      # ['2020-01-01', '2020-02-01']
+print(r["v"])      # [15.0, 40.0]
+print(r["count"])  # [2, 3]   <- densidad: nº de observaciones por mes
+print(r["freq"], r["downsampled"])  # monthly False
+
+# freq='auto' infiere la granularidad del delta mediano entre fechas.
+mensual = [f"2022-{m:02d}-01" for m in range(1, 13)]
+print(resample_timeseries(mensual, list(range(1, 13)))["freq"])  # monthly
+```
+
+## Cuando usarla
+
+- Usala en el capitulo TIMESERIES de `AutomaticEDA` para construir, a partir de una columna temporal (`detect_time_column`) y una columna numerica, la doble serie que el renderer dibuja: la EVOLUCION del valor agregado por periodo y el CONTEO de observaciones por periodo.
+- Cuando ya tengas las fechas y los valores leidos en memoria (de DuckDB, polars, CSV, etc.) y solo necesites agregarlos por dia/semana/mes/trimestre/año sin volver a tocar la base de datos — esta funcion es pura y recibe los datos por parametro.
+- Cuando quieras un downsampling controlado para que una serie muy larga (miles de fechas) quepa en un grafico de un PDF/PPTX sin saturarlo, conservando el primer y el ultimo punto.
+- Cuando no sepas la cadencia de la serie: pasa `freq="auto"` y deja que la infiera del delta mediano.
+
+## Gotchas
+
+- Funcion pura, sin I/O y determinista. NUNCA lanza: ante entrada invalida (listas vacias, longitudes distintas o todas las fechas no parseables) devuelve listas vacias + `note="datos insuficientes"`.
+- `count` cuenta OBSERVACIONES con fecha valida en el bucket (densidad temporal), aunque su valor numerico sea `None`/no numerico. `v` agrega SOLO los valores numericos validos del bucket; si no hay ninguno, `v` del bucket es `None` mientras `count` sigue reflejando las filas. No confundas `count` (filas) con el nº de valores agregados.
+- `bool`, `NaN` e `Inf` se tratan como NO numericos (se ignoran en `v`). Un string que no parsea a numero tambien se ignora en `v` pero su fila cuenta si la fecha es valida.
+- El truncado de bucket usa el inicio del periodo: semana = lunes ISO (`weekday()==0`), mes = dia 1, trimestre = primer dia del trimestre (ene/abr/jul/oct), año = 1 de enero. La etiqueta de cada bucket es esa fecha de inicio en ISO `YYYY-MM-DD`, no un rango.
+- El downsampling (`n_buckets > max_points`) reduce la salida a `<= max_points` puntos equiespaciados conservando primero y ultimo, pero `n_buckets` SIEMPRE reporta el conteo real previo al recorte. Si necesitas todos los buckets, sube `max_points` o ponlo `<=0`.
+- Las fechas con hora se truncan a su `date()` antes de agrupar: la granularidad minima es el dia (no hay buckets horarios).
+- `freq` desconocida o no-string cae a `"auto"`; `agg` desconocida cae a `"mean"`. El campo devuelto refleja la opcion efectivamente usada.
diff --git a/python/functions/datascience/resample_timeseries.py b/python/functions/datascience/resample_timeseries.py
new file mode 100644
index 00000000..c3e49a26
--- /dev/null
+++ b/python/functions/datascience/resample_timeseries.py
@@ -0,0 +1,275 @@
+"""Agrega una serie temporal por periodo para el capitulo TIMESERIES (grupo eda).
+
+Funcion pura y determinista: recibe las fechas y los valores YA leidos (nunca
+toca una base de datos ni hace I/O) y los agrega por bucket temporal para poder
+graficar la evolucion de la serie y, en paralelo, el CONTEO de observaciones por
+periodo (densidad temporal).
+
+Estilo "dict-no-throw" del grupo eda: NUNCA lanza excepcion, siempre devuelve el
+mismo conjunto de claves. Lectura y parseo de fechas 100% defensivos. Solo usa la
+libreria estandar (``datetime``, ``statistics``, ``re``).
+"""
+
+from __future__ import annotations
+
+import datetime
+import re
+import statistics
+
+# Frecuencias soportadas, de mas fina a mas gruesa.
+_FREQS = ("daily", "weekly", "monthly", "quarterly", "yearly")
+
+# Agregaciones soportadas.
+_AGGS = ("mean", "sum", "median", "last", "min", "max")
+
+# Acepta el inicio de una fecha ISO con cualquier separador posterior
+# (incluido un caracter raro entre la fecha y la hora).
+_DATE_RE = re.compile(r"(\d{4})-(\d{2})-(\d{2})")
+
+
+def _to_date(x) -> "datetime.date | None":
+    """Parsea defensivamente un valor a ``datetime.date``; devuelve None si falla."""
+    if x is None:
+        return None
+    # datetime es subclase de date: comprobarlo primero.
+    if isinstance(x, datetime.datetime):
+        return x.date()
+    if isinstance(x, datetime.date):
+        return x
+    s = str(x).strip()
+    if not s:
+        return None
+    # Camino feliz: ISO completo (con o sin hora, con o sin 'Z' final).
+    try:
+        s2 = s[:-1] if s.endswith("Z") else s
+        return datetime.datetime.fromisoformat(s2).date()
+    except ValueError:
+        pass
+    # Fallback robusto: extrae el prefijo YYYY-MM-DD con cualquier separador.
+    m = _DATE_RE.match(s)
+    if m:
+        try:
+            return datetime.date(int(m.group(1)), int(m.group(2)), int(m.group(3)))
+        except ValueError:
+            return None
+    return None
+
+
+def _to_number(x) -> "float | None":
+    """Convierte a float si es numerico finito; devuelve None en otro caso."""
+    if x is None:
+        return None
+    if isinstance(x, bool):
+        # bool es subclase de int: lo tratamos como no-numerico para una serie.
+        return None
+    try:
+        f = float(x)
+    except (TypeError, ValueError):
+        return None
+    # Descarta NaN / Inf (no agregables de forma estable).
+    if f != f or f in (float("inf"), float("-inf")):
+        return None
+    return f
+
+
+def _infer_freq(dates_sorted: list) -> str:
+    """Infiere la frecuencia desde el delta mediano (en dias) entre fechas."""
+    if len(dates_sorted) < 2:
+        return "daily"
+    diffs = [
+        (dates_sorted[i + 1] - dates_sorted[i]).days
+        for i in range(len(dates_sorted) - 1)
+    ]
+    diffs = [d for d in diffs if d > 0]  # ignora duplicados del mismo dia
+    if not diffs:
+        return "daily"
+    med = statistics.median(diffs)
+    if med <= 3:
+        return "daily"
+    if med <= 16:
+        return "weekly"
+    if med <= 75:
+        return "monthly"
+    if med <= 200:
+        return "quarterly"
+    return "yearly"
+
+
+def _bucket_start(d: "datetime.date", freq: str) -> "datetime.date":
+    """Trunca una fecha al inicio de su bucket segun la frecuencia."""
+    if freq == "weekly":
+        return d - datetime.timedelta(days=d.weekday())  # lunes ISO
+    if freq == "monthly":
+        return datetime.date(d.year, d.month, 1)
+    if freq == "quarterly":
+        first_month = ((d.month - 1) // 3) * 3 + 1
+        return datetime.date(d.year, first_month, 1)
+    if freq == "yearly":
+        return datetime.date(d.year, 1, 1)
+    return d  # daily (o cualquier otra cosa): la propia fecha
+
+
+def _downsample_indices(n: int, max_points: int) -> list:
+    """Indices equiespaciados conservando primero y ultimo (<= max_points)."""
+    if max_points <= 0 or max_points >= n:
+        return list(range(n))
+    if max_points == 1:
+        return [0]
+    idx = sorted({round(i * (n - 1) / (max_points - 1)) for i in range(max_points)})
+    return idx
+
+
+def _empty(freq_req: str, agg: str) -> dict:
+    """Resultado canonico cuando no hay datos suficientes."""
+    eff_freq = freq_req if freq_req in _FREQS else "auto"
+    return {
+        "t": [],
+        "v": [],
+        "count": [],
+        "freq": eff_freq,
+        "agg": agg if agg in _AGGS else "mean",
+        "n_in": 0,
+        "n_buckets": 0,
+        "downsampled": False,
+        "note": "datos insuficientes",
+    }
+
+
+def resample_timeseries(
+    t: list,
+    v: list,
+    freq: str = "auto",
+    agg: str = "mean",
+    max_points: int = 400,
+) -> dict:
+    """Agrega una serie temporal por periodo (buckets) para graficarla.
+
+    Empareja ``t[i]`` con ``v[i]`` por indice, descarta los pares cuya fecha no
+    parsea, trunca cada fecha al inicio de su bucket segun ``freq`` y agrupa. Por
+    cada bucket devuelve el valor agregado (``agg`` sobre los valores numericos
+    validos) y el CONTEO de observaciones con fecha valida (densidad temporal),
+    independientemente de si su valor numerico es ``None``.
+
+    Funcion pura: no hace I/O, no muta los inputs, es determinista, NUNCA lanza.
+
+    Args:
+        t: lista de fechas paralela a ``v``. Acepta strings ISO
+            (``"YYYY-MM-DD"`` o ``"YYYY-MM-DDTHH:MM:SS"``, con ``Z`` opcional),
+            ``datetime.date`` o ``datetime.datetime``. Se parsea defensivamente;
+            las fechas que no parsean se descartan junto con su valor.
+        v: lista de valores numericos (float/int). Puede contener ``None`` o
+            valores no numericos: estos se ignoran en la agregacion, pero la fila
+            sigue contando en ``count`` (siempre que su fecha sea valida).
+        freq: ``"auto"`` (infiere del delta mediano entre fechas) o uno de
+            ``"daily"``, ``"weekly"``, ``"monthly"``, ``"quarterly"``,
+            ``"yearly"``. Una frecuencia desconocida cae a ``"auto"``.
+        agg: agregacion por bucket: ``"mean"``, ``"sum"``, ``"median"``,
+            ``"last"`` (valor de la observacion cronologicamente mas reciente),
+            ``"min"`` o ``"max"``. Una agregacion desconocida cae a ``"mean"``.
+        max_points: si tras agregar hay mas buckets que este limite, se hace
+            downsampling uniforme (1 de cada k buckets equiespaciados,
+            conservando el primero y el ultimo) para no saturar el grafico.
+
+    Returns:
+        Siempre un dict con las mismas claves::
+
+            {
+              "t": [str, ...],         # etiqueta ISO YYYY-MM-DD de cada bucket
+              "v": [float|None, ...],  # valor agregado por bucket (None si vacio)
+              "count": [int, ...],     # nº de observaciones con fecha valida
+              "freq": str,             # frecuencia efectivamente usada
+              "agg": str,              # agregacion usada
+              "n_in": int,             # nº de pares (t,v) con fecha valida
+              "n_buckets": int,        # nº de buckets antes del downsample
+              "downsampled": bool,     # True si se aplico downsampling
+              "note": str,             # "" o nota (p.ej. "datos insuficientes")
+            }
+    """
+    agg = agg if agg in _AGGS else "mean"
+    freq_req = freq if isinstance(freq, str) else "auto"
+
+    # Validacion de entrada: deben ser listas de igual longitud y no vacias.
+    if (
+        not isinstance(t, list)
+        or not isinstance(v, list)
+        or len(t) == 0
+        or len(t) != len(v)
+    ):
+        return _empty(freq_req, agg)
+
+    # Empareja por indice y descarta fechas no parseables.
+    parsed: list = []  # (date, original_index, number_or_None)
+    for i, (ti, vi) in enumerate(zip(t, v)):
+        d = _to_date(ti)
+        if d is None:
+            continue
+        parsed.append((d, i, _to_number(vi)))
+
+    n_in = len(parsed)
+    if n_in == 0:
+        return _empty(freq_req, agg)
+
+    # Resuelve la frecuencia efectiva.
+    if freq_req in _FREQS:
+        eff_freq = freq_req
+    else:
+        dates_sorted = sorted(d for d, _, _ in parsed)
+        eff_freq = _infer_freq(dates_sorted)
+
+    # Agrupa por bucket.
+    buckets: dict = {}
+    for d, idx, num in parsed:
+        b = _bucket_start(d, eff_freq)
+        slot = buckets.get(b)
+        if slot is None:
+            slot = {"count": 0, "vals": [], "last_key": None, "last_val": None}
+            buckets[b] = slot
+        slot["count"] += 1
+        if num is not None:
+            slot["vals"].append(num)
+            key = (d, idx)
+            if slot["last_key"] is None or key > slot["last_key"]:
+                slot["last_key"] = key
+                slot["last_val"] = num
+
+    ordered = sorted(buckets.items(), key=lambda kv: kv[0])
+    n_buckets = len(ordered)
+
+    def _aggregate(vals: list, last_val) -> "float | None":
+        if not vals:
+            return None
+        if agg == "sum":
+            return float(sum(vals))
+        if agg == "median":
+            return float(statistics.median(vals))
+        if agg == "last":
+            return float(last_val) if last_val is not None else None
+        if agg == "min":
+            return float(min(vals))
+        if agg == "max":
+            return float(max(vals))
+        return float(statistics.fmean(vals))  # mean (default)
+
+    t_out = [b.isoformat() for b, _ in ordered]
+    v_out = [_aggregate(s["vals"], s["last_val"]) for _, s in ordered]
+    c_out = [s["count"] for _, s in ordered]
+
+    downsampled = False
+    if n_buckets > max_points > 0:
+        keep = _downsample_indices(n_buckets, max_points)
+        t_out = [t_out[i] for i in keep]
+        v_out = [v_out[i] for i in keep]
+        c_out = [c_out[i] for i in keep]
+        downsampled = True
+
+    return {
+        "t": t_out,
+        "v": v_out,
+        "count": c_out,
+        "freq": eff_freq,
+        "agg": agg,
+        "n_in": n_in,
+        "n_buckets": n_buckets,
+        "downsampled": downsampled,
+        "note": "",
+    }
diff --git a/python/functions/datascience/resample_timeseries_test.py b/python/functions/datascience/resample_timeseries_test.py
new file mode 100644
index 00000000..58472865
--- /dev/null
+++ b/python/functions/datascience/resample_timeseries_test.py
@@ -0,0 +1,118 @@
+"""Tests para resample_timeseries (grupo eda)."""
+
+import datetime
+import os
+import sys
+
+sys.path.insert(0, os.path.dirname(__file__))
+
+from resample_timeseries import resample_timeseries
+
+
+def test_daily_a_mensual_mean():
+    # Serie diaria agregada a buckets mensuales con agg="mean".
+    t = [
+        "2020-01-01", "2020-01-15",
+        "2020-02-01", "2020-02-10", "2020-02-20",
+    ]
+    v = [10.0, 20.0, 30.0, 40.0, 50.0]
+    r = resample_timeseries(t, v, freq="monthly", agg="mean")
+
+    assert r["t"] == ["2020-01-01", "2020-02-01"]
+    assert r["v"] == [15.0, 40.0]      # (10+20)/2 ; (30+40+50)/3
+    assert r["count"] == [2, 3]
+    assert r["freq"] == "monthly"
+    assert r["agg"] == "mean"
+    assert r["n_in"] == 5
+    assert r["n_buckets"] == 2
+    assert r["downsampled"] is False
+    assert r["note"] == ""
+
+
+def test_agg_sum_y_last():
+    t = [
+        "2020-01-01", "2020-01-15",
+        "2020-02-01", "2020-02-10", "2020-02-20",
+    ]
+    v = [10.0, 20.0, 30.0, 40.0, 50.0]
+
+    r_sum = resample_timeseries(t, v, freq="monthly", agg="sum")
+    assert r_sum["v"] == [30.0, 120.0]
+    assert r_sum["agg"] == "sum"
+
+    # last = valor de la observacion cronologicamente mas reciente del bucket,
+    # aunque el orden de entrada este desordenado.
+    t2 = ["2020-02-20", "2020-02-01", "2020-02-10", "2020-01-15", "2020-01-01"]
+    v2 = [50.0, 30.0, 40.0, 20.0, 10.0]
+    r_last = resample_timeseries(t2, v2, freq="monthly", agg="last")
+    assert r_last["t"] == ["2020-01-01", "2020-02-01"]
+    assert r_last["v"] == [20.0, 50.0]   # Jan->2020-01-15=20 ; Feb->2020-02-20=50
+    assert r_last["agg"] == "last"
+
+
+def test_count_cuenta_observacion_con_valor_none():
+    # Un bucket con un valor None: count cuenta la fila, v ignora el None.
+    t = ["2020-03-05", "2020-03-06", "2020-03-20"]
+    v = [None, 7.0, 9.0]
+    r = resample_timeseries(t, v, freq="monthly", agg="mean")
+
+    assert r["t"] == ["2020-03-01"]
+    assert r["count"] == [3]            # 3 filas con fecha valida
+    assert r["v"] == [8.0]             # media de los validos: (7+9)/2
+    assert r["n_in"] == 3
+
+    # Bucket entero sin ningun valor numerico valido -> v = None, count sigue.
+    r2 = resample_timeseries(
+        ["2020-04-01", "2020-04-02"], [None, "n/a"], freq="monthly"
+    )
+    assert r2["t"] == ["2020-04-01"]
+    assert r2["count"] == [2]
+    assert r2["v"] == [None]
+
+
+def test_downsampling_respeta_max_points_y_extremos():
+    base = datetime.date(2021, 1, 1)
+    t = [(base + datetime.timedelta(days=i)).isoformat() for i in range(500)]
+    v = [float(i) for i in range(500)]
+    r = resample_timeseries(t, v, freq="daily", agg="mean", max_points=400)
+
+    assert r["n_buckets"] == 500
+    assert r["downsampled"] is True
+    assert len(r["t"]) <= 400
+    assert len(r["t"]) == len(r["v"]) == len(r["count"])
+    # Primero y ultimo bucket conservados.
+    assert r["t"][0] == "2021-01-01"
+    assert r["t"][-1] == (base + datetime.timedelta(days=499)).isoformat()
+
+
+def test_freq_auto_infiere_mensual():
+    # Fechas separadas ~1 mes -> auto infiere "monthly".
+    t = [f"2022-{m:02d}-01" for m in range(1, 13)]
+    v = [float(m) for m in range(1, 13)]
+    r = resample_timeseries(t, v, freq="auto", agg="mean")
+
+    assert r["freq"] == "monthly"
+    assert r["n_buckets"] == 12
+    assert r["count"] == [1] * 12
+
+    # Fechas diarias consecutivas -> auto infiere "daily".
+    base = datetime.date(2023, 1, 1)
+    td = [(base + datetime.timedelta(days=i)).isoformat() for i in range(20)]
+    rd = resample_timeseries(td, [float(i) for i in range(20)], freq="auto")
+    assert rd["freq"] == "daily"
+
+
+def test_edge_listas_vacias_o_desiguales():
+    vacio = resample_timeseries([], [])
+    assert vacio["t"] == [] and vacio["v"] == [] and vacio["count"] == []
+    assert vacio["note"] == "datos insuficientes"
+    assert vacio["n_in"] == 0 and vacio["n_buckets"] == 0
+
+    desigual = resample_timeseries(["2020-01-01", "2020-01-02"], [1.0])
+    assert desigual["note"] == "datos insuficientes"
+    assert desigual["t"] == []
+
+    # Todas las fechas invalidas -> tambien insuficiente.
+    invalidas = resample_timeseries(["no-fecha", "tampoco"], [1.0, 2.0])
+    assert invalidas["note"] == "datos insuficientes"
+    assert invalidas["n_in"] == 0