§22 S6: per-collection enabled_models — the §22.12 model-universe chain

A collection's .collection.yaml may carry an enabled_models list that NARROWS
its project's universe, which narrows the deployment ENABLED_MODELS. Resolution
(extending §6.6/§6.7): funder ∩ per-entry models ∩ collection ∩ project, with
the operator providers as the ceiling.

- migration 031: additive collections.config_json (parallels projects.config_json).
- registry.parse_collection_manifest: read enabled_models into CollectionEntry.config
  (absent = inherit, present incl. [] = narrow; [] opts the collection out of AI);
  reject a non-list. _upsert_named_collection persists config_json. The default
  collection (from projects.yaml) leaves it NULL — it inherits the project.
- models_resolver: _scope_narrowed_universe narrows the operator universe by the
  entry's project then collection enabled_models; the funder universe is bounded
  by it too. A collection cannot widen its project (narrowing from the ceiling).
- collections.get_collection surfaces enabled_models; GET
  /api/projects/:id/collections/:cid returns it.
- test_s6_collection_models_vertical.py: 9 cases (parse, the narrowing chain
  incl. opt-out + cannot-widen, API surfacing).

Backend: 525 passed. Per SPEC §22.12. Releases as part of v0.45.0.

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

backend/app/models_resolver.py

@@ -38,22 +38,78 @@ from . import db, funder
 from .providers import BaseProvider
 
 
+def _models_from_config(config_json: str | None) -> list[str] | None:
+    """The `enabled_models` list inside a project/collection `config_json`,
+    or None when the key is absent (meaning "no narrowing at this tier")."""
+    if not config_json:
+        return None
+    try:
+        cfg = json.loads(config_json)
+    except (json.JSONDecodeError, TypeError):
+        return None
+    em = cfg.get("enabled_models") if isinstance(cfg, dict) else None
+    return [str(m) for m in em] if isinstance(em, list) else None
+
+
+def _narrow(universe: list[str], allowed: list[str] | None) -> list[str]:
+    """Intersect `universe` with `allowed`, preserving universe order. `allowed`
+    None means no narrowing at this tier; an empty list narrows to empty (an
+    opt-out), exactly like the §6.6 per-entry `models: []`."""
+    if allowed is None:
+        return universe
+    allow = set(allowed)
+    return [k for k in universe if k in allow]
+
+
+def _scope_narrowed_universe(
+    collection_id: str | None, operator_keys: list[str]
+) -> list[str]:
+    """§22.12 — narrow the operator (deployment) universe by the entry's
+    project then its collection `enabled_models`. Each tier may only narrow;
+    a missing config at a tier is a no-op. The collection cannot widen its
+    project because narrowing composes from the operator ceiling downward."""
+    if collection_id is None:
+        return list(operator_keys)
+    conn = db.conn()
+    crow = conn.execute(
+        "SELECT project_id, config_json FROM collections WHERE id = ?",
+        (collection_id,),
+    ).fetchone()
+    universe = list(operator_keys)
+    if crow is None:
+        return universe
+    prow = conn.execute(
+        "SELECT config_json FROM projects WHERE id = ?", (crow["project_id"],)
+    ).fetchone()
+    universe = _narrow(universe, _models_from_config(prow["config_json"] if prow else None))
+    universe = _narrow(universe, _models_from_config(crow["config_json"]))
+    return universe
+
+
 def resolve_models_for_rfc(
     slug: str, providers: dict[str, BaseProvider]
 ) -> list[str]:
-    """Return the per-RFC resolved model keys per §6.6, extended by §6.7.
+    """Return the per-RFC resolved model keys per §6.6, extended by §6.7 and
+    §22.12.
 
     The first entry is the RFC's default model. An empty list means
     AI is unavailable on this RFC and callers refuse the AI surface.
     """
-    # §6.7: the funder universe (if any) replaces the operator universe
-    # as the base set the §6.6 frontmatter intersects against.
-    funder_universe = funder.resolve_funder_universe(slug, providers)
-    base_universe = funder_universe if funder_universe is not None else list(providers.keys())
     row = db.conn().execute(
-        "SELECT models_json FROM cached_rfcs WHERE slug = ?",
+        "SELECT collection_id, models_json FROM cached_rfcs WHERE slug = ?",
         (slug,),
     ).fetchone()
+    collection_id = row["collection_id"] if row is not None else None
+    # §22.12: first narrow the operator universe by the entry's project +
+    # collection enabled_models (the deployment → project → collection chain).
+    scope_universe = _scope_narrowed_universe(collection_id, list(providers.keys()))
+    # §6.7: a consenting funder universe (if any) replaces the operator universe
+    # as the base set — still bounded by the §22.12 scope narrowing above.
+    funder_universe = funder.resolve_funder_universe(slug, providers)
+    if funder_universe is not None:
+        base_universe = _narrow(list(funder_universe), scope_universe)
+    else:
+        base_universe = scope_universe
     if row is None or row["models_json"] is None:
         return list(base_universe)
     try: