§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/collections.py

@@ -8,11 +8,26 @@ authz (auth.py) recovers a row's project by joining `collections` on
 """
 from __future__ import annotations
 
+import json
+
 from . import db
 
 DEFAULT_COLLECTION_ID = "default"
 
 
+def _enabled_models_from_config(config_json: str | None) -> list[str] | None:
+    """§22.12 per-collection enabled_models from a `config_json` blob, or None
+    when unset (the collection inherits its project's universe)."""
+    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 default_collection_id(project_id: str) -> str:
     """The id of a project's default (S1: sole) collection. Falls back to the
     literal 'default' when the project has no collection row yet."""
@@ -60,13 +75,18 @@ def subfolder_of(collection_id: str) -> str:
 
 
 def get_collection(collection_id: str) -> dict | None:
-    """The full collection row as a dict, or None if unknown."""
+    """The full collection row as a dict, or None if unknown. `enabled_models`
+    (§22.12) is unpacked from `config_json` as a list, or None when unset."""
     row = db.conn().execute(
-        "SELECT id, project_id, type, subfolder, initial_state, visibility, name "
-        "FROM collections WHERE id = ?",
+        "SELECT id, project_id, type, subfolder, initial_state, visibility, name, "
+        "config_json FROM collections WHERE id = ?",
         (collection_id,),
     ).fetchone()
-    return dict(row) if row else None
+    if row is None:
+        return None
+    out = dict(row)
+    out["enabled_models"] = _enabled_models_from_config(out.pop("config_json", None))
+    return out
 
 
 def list_collections(project_id: str, include_unlisted: bool = False) -> list[dict]: