diff --git a/src/adm_cli/model.py b/src/adm_cli/model.py
new file mode 100644
index 0000000..a5b10a7
--- /dev/null
+++ b/src/adm_cli/model.py
@@ -0,0 +1,131 @@
+"""Spec Kit handoff — seed a feature directory from a ratcheted contract."""
+
+from __future__ import annotations
+
+import json
+from datetime import date
+from pathlib import Path
+
+
+def generate_feature_json(
+    domain: str,
+    contract_version: str,
+    contract_path: Path,
+    schema_path: Path,
+) -> dict:
+    """Generate feature.json metadata for Spec Kit consumption."""
+    return {
+        "name": f"{domain}-engine",
+        "source": "adm-kit",
+        "domain": domain,
+        "contract_version": contract_version,
+        "contract_path": str(contract_path),
+        "schema_path": str(schema_path),
+        "generated": date.today().isoformat(),
+    }
+
+
+def generate_spec_seed(
+    domain: str,
+    contract_version: str,
+    schema: dict,
+    invariants: list[dict] | None = None,
+) -> str:
+    """Generate a Spec Kit-compatible spec.md seed from a contract schema."""
+    properties = schema.get("properties", {})
+    required = set(schema.get("required", []))
+
+    lines = [
+        f"# Feature Specification: {domain.title()} Engine",
+        "",
+        f"**Source**: ADM Kit ratcheted contract v{contract_version}",
+        f"**Generated**: {date.today().isoformat()}",
+        "",
+        "## Context",
+        "",
+        f"This specification was generated from the validated and ratcheted ADM contract for the `{domain}` data domain. "
+        "All requirements trace back to discovered data invariants and validated schema fields.",
+        "",
+        "## Key Entities",
+        "",
+        f"### {domain.title()}Record",
+        "",
+        "| Field | Type | Required | Description |",
+        "|-------|------|----------|-------------|",
+    ]
+
+    for field_name, field_def in properties.items():
+        field_type = field_def.get("type", "any")
+        is_required = "Yes" if field_name in required else "No"
+        description = field_def.get("description", "—")
+        lines.append(f"| {field_name} | {field_type} | {is_required} | {description} |")
+
+    lines.extend([
+        "",
+        "## Functional Requirements",
+        "",
+    ])
+
+    for i, (field_name, field_def) in enumerate(properties.items(), start=1):
+        constraint = ""
+        if "minimum" in field_def:
+            constraint = f" (minimum: {field_def['minimum']})"
+        elif "pattern" in field_def:
+            constraint = f" (pattern: `{field_def['pattern']}`)"
+        lines.append(f"- **FR-{i:03d}**: System MUST store and validate `{field_name}`{constraint}")
+
+    if invariants:
+        lines.extend([
+            "",
+            "## Acceptance Criteria (from Invariants)",
+            "",
+        ])
+        for inv in invariants:
+            inv_id = inv.get("id", "INV-???")
+            description = inv.get("description", inv.get("title", ""))
+            lines.append(f"- **{inv_id}**: {description}")
+
+    lines.extend([
+        "",
+        "## Traceability",
+        "",
+        "| Requirement | Source |",
+        "|-------------|--------|",
+    ])
+    for i, field_name in enumerate(properties.keys(), start=1):
+        lines.append(f"| FR-{i:03d} | contract.{field_name} |")
+
+    lines.append("")
+    return "\n".join(lines)
+
+
+def seed_feature_directory(
+    domain: str,
+    contract_version: str,
+    contract_path: Path,
+    schema_path: Path,
+    invariants_path: Path | None,
+    specs_dir: Path,
+) -> Path:
+    """Create a Spec Kit feature directory seeded from the ADM contract.
+
+    Returns the path to the created feature directory.
+    """
+    existing = sorted(specs_dir.glob("[0-9]*")) if specs_dir.exists() else []
+    next_num = len(existing) + 1
+    feature_dir = specs_dir / f"{next_num:03d}-{domain}-engine"
+    feature_dir.mkdir(parents=True, exist_ok=True)
+
+    schema = json.loads(schema_path.read_text())
+
+    feature_meta = generate_feature_json(domain, contract_version, contract_path, schema_path)
+    (feature_dir / "feature.json").write_text(json.dumps(feature_meta, indent=2) + "\n")
+
+    invariants = None
+    if invariants_path and invariants_path.exists():
+        invariants = json.loads(invariants_path.read_text()).get("invariants", [])
+
+    spec_content = generate_spec_seed(domain, contract_version, schema, invariants)
+    (feature_dir / "spec.md").write_text(spec_content)
+
+    return feature_dir
diff --git a/tests/test_model.py b/tests/test_model.py
new file mode 100644
index 0000000..140c4b2
--- /dev/null
+++ b/tests/test_model.py
@@ -0,0 +1,120 @@
+"""Tests for Spec Kit handoff (/adm.model)."""
+
+import json
+from pathlib import Path
+
+from adm_cli.model import generate_feature_json, generate_spec_seed, seed_feature_directory
+
+
+class TestGenerateFeatureJson:
+    def test_structure(self):
+        result = generate_feature_json(
+            domain="holdings",
+            contract_version="1.0.0",
+            contract_path=Path("artefacts/holdings/6-contracts/v1.0.0/contract.py"),
+            schema_path=Path("artefacts/holdings/6-contracts/v1.0.0/contract.schema.json"),
+        )
+        assert result["name"] == "holdings-engine"
+        assert result["source"] == "adm-kit"
+        assert result["domain"] == "holdings"
+        assert result["contract_version"] == "1.0.0"
+        assert "generated" in result
+
+
+class TestGenerateSpecSeed:
+    def test_includes_fields_as_requirements(self):
+        schema = {
+            "properties": {
+                "account_id": {"type": "string", "pattern": "^ACC-\\d{4}$"},
+                "balance": {"type": "number", "minimum": 0},
+            },
+            "required": ["account_id", "balance"],
+        }
+        result = generate_spec_seed("holdings", "1.0.0", schema)
+        assert "FR-001" in result
+        assert "account_id" in result
+        assert "FR-002" in result
+        assert "balance" in result
+        assert "pattern" in result
+        assert "minimum" in result
+
+    def test_includes_invariants_as_ac(self):
+        schema = {"properties": {"name": {"type": "string"}}, "required": ["name"]}
+        invariants = [
+            {"id": "INV-001", "description": "name is never null"},
+            {"id": "INV-002", "description": "name is unique"},
+        ]
+        result = generate_spec_seed("holdings", "1.0.0", schema, invariants)
+        assert "INV-001" in result
+        assert "name is never null" in result
+        assert "INV-002" in result
+
+    def test_traceability_table(self):
+        schema = {"properties": {"x": {"type": "string"}, "y": {"type": "integer"}}, "required": []}
+        result = generate_spec_seed("test", "1.0.0", schema)
+        assert "| FR-001 | contract.x |" in result
+        assert "| FR-002 | contract.y |" in result
+
+
+class TestSeedFeatureDirectory:
+    def test_creates_directory_and_files(self, tmp_path: Path):
+        schema_path = tmp_path / "contract.schema.json"
+        schema_path.write_text(json.dumps({
+            "properties": {"name": {"type": "string"}},
+            "required": ["name"],
+        }))
+        contract_path = tmp_path / "contract.py"
+        contract_path.write_text("# contract\n")
+        specs_dir = tmp_path / "specs"
+
+        result = seed_feature_directory(
+            domain="holdings",
+            contract_version="1.0.0",
+            contract_path=contract_path,
+            schema_path=schema_path,
+            invariants_path=None,
+            specs_dir=specs_dir,
+        )
+        assert result.name == "001-holdings-engine"
+        assert (result / "feature.json").exists()
+        assert (result / "spec.md").exists()
+
+    def test_sequential_numbering(self, tmp_path: Path):
+        specs_dir = tmp_path / "specs"
+        (specs_dir / "001-existing").mkdir(parents=True)
+
+        schema_path = tmp_path / "schema.json"
+        schema_path.write_text(json.dumps({"properties": {}, "required": []}))
+        contract_path = tmp_path / "contract.py"
+        contract_path.write_text("")
+
+        result = seed_feature_directory(
+            domain="cashflows",
+            contract_version="1.0.0",
+            contract_path=contract_path,
+            schema_path=schema_path,
+            invariants_path=None,
+            specs_dir=specs_dir,
+        )
+        assert result.name == "002-cashflows-engine"
+
+    def test_includes_invariants(self, tmp_path: Path):
+        schema_path = tmp_path / "schema.json"
+        schema_path.write_text(json.dumps({"properties": {"x": {"type": "string"}}, "required": []}))
+        contract_path = tmp_path / "contract.py"
+        contract_path.write_text("")
+        inv_path = tmp_path / "invariants.json"
+        inv_path.write_text(json.dumps({"invariants": [{"id": "INV-001", "description": "x is unique"}]}))
+        specs_dir = tmp_path / "specs"
+
+        result = seed_feature_directory(
+            domain="test",
+            contract_version="2.0.0",
+            contract_path=contract_path,
+            schema_path=schema_path,
+            invariants_path=inv_path,
+            specs_dir=specs_dir,
+        )
+        spec_content = (result / "spec.md").read_text()
+        assert "INV-001" in spec_content
+        assert "x is unique" in spec_content