diff --git a/registry/models.go b/registry/models.go
new file mode 100644
index 00000000..06346058
--- /dev/null
+++ b/registry/models.go
@@ -0,0 +1,93 @@
+package registry
+
+import "time"
+
+// Kind classifies a registry entry.
+type Kind string
+
+const (
+	KindFunction  Kind = "function"
+	KindPipeline  Kind = "pipeline"
+	KindComponent Kind = "component"
+)
+
+// Purity indicates whether a function has side effects.
+type Purity string
+
+const (
+	PurityPure   Purity = "pure"
+	PurityImpure Purity = "impure"
+)
+
+// Algebraic classifies a type.
+type Algebraic string
+
+const (
+	AlgebraicProduct Algebraic = "product"
+	AlgebraicSum     Algebraic = "sum"
+)
+
+// Function represents an entry in the functions table.
+// Covers kind: function, pipeline, and component.
+type Function struct {
+	ID              string   `json:"id"`
+	Name            string   `json:"name"`
+	Kind            Kind     `json:"kind"`
+	Lang            string   `json:"lang"`
+	Domain          string   `json:"domain"`
+	Version         string   `json:"version"`
+	Purity          Purity   `json:"purity"`
+	Signature       string   `json:"signature"`
+	Description     string   `json:"description"`
+	Tags            []string `json:"tags"`
+	UsesFunctions   []string `json:"uses_functions"`
+	UsesTypes       []string `json:"uses_types"`
+	Returns         []string `json:"returns"`
+	ReturnsOptional bool     `json:"returns_optional"`
+	ErrorType       string   `json:"error_type"`
+	Imports         []string `json:"imports"`
+	Example         string   `json:"example"`
+	Tested          bool     `json:"tested"`
+	Tests           []string `json:"tests"`
+	TestFilePath    string   `json:"test_file_path"`
+	FilePath        string   `json:"file_path"`
+	CreatedAt       time.Time `json:"created_at"`
+	UpdatedAt       time.Time `json:"updated_at"`
+
+	// Component-only fields (kind: component)
+	Props    []PropDef `json:"props,omitempty"`
+	Emits    []string  `json:"emits,omitempty"`
+	HasState *bool     `json:"has_state,omitempty"`
+	Framework string   `json:"framework,omitempty"`
+	Variant  []string  `json:"variant,omitempty"`
+}
+
+// PropDef describes a component prop.
+type PropDef struct {
+	Name        string `json:"name"`
+	Type        string `json:"type"`
+	Required    bool   `json:"required"`
+	Description string `json:"description"`
+}
+
+// Type represents an entry in the types table.
+type Type struct {
+	ID         string    `json:"id"`
+	Name       string    `json:"name"`
+	Lang       string    `json:"lang"`
+	Domain     string    `json:"domain"`
+	Version    string    `json:"version"`
+	Algebraic  Algebraic `json:"algebraic"`
+	Definition string    `json:"definition"`
+	Description string   `json:"description"`
+	Tags       []string  `json:"tags"`
+	UsesTypes  []string  `json:"uses_types"`
+	FilePath   string    `json:"file_path"`
+	CreatedAt  time.Time `json:"created_at"`
+	UpdatedAt  time.Time `json:"updated_at"`
+}
+
+// GenerateID builds the canonical ID: {name}_{lang}_{domain}
+func GenerateID(name, lang, domain string) string {
+	return name + "_" + lang + "_" + domain
+}