fix(provider): sortable_chunk_fields needs required type — handshake was broken

DEPLOY-BREAKER caught by driving the live bind (unit tests + worldtree-dev's
name-only parser + heid-bug-hunt all missed it). bifrost handshake_response
`SortableChunkField` requires BOTH `name` and `type` (additionalProperties:false).
We advertised `[{"name":"updated_at"}]` (no `type`), so the handshake_response
failed wire-schema validation → `bifrost.schema_validation_failed` → the ENTIRE
Bifrost bind (memory + affect) broke, not just the sort. Advertise
`{"name":"updated_at","type":"timestamp"}` (matches the reference; `type` is
advisory-only). Regression guard added to the caps test (asserts required name+type,
no extra keys). Full suite 639 green.

docs/contracts/bifrost_memory_provider.contract.md

@@ -119,10 +119,14 @@ interpreted.
   `describe_store` advertises ONLY what is implemented: `relational_edges_supported=False`,
   `atomic_supersede_supported=False`, `transaction_supported=False`,
   `optimistic_locking_supported=True`, `filterable_metadata_fields=[]`,
-  **`sortable_chunk_fields=[{"name": "updated_at"}]`** (the ONLY globally-sortable field;
-  gates `scan`'s sort at the bifrost dispatch `_validate_scan_sort` AND Worldtree's #349
-  person-prime Branch-A `"updated_at" in caps.sort_fields_supported` — advertising it is
-  what lights up turn-1 durable-fact injection).
+  **`sortable_chunk_fields=[{"name": "updated_at", "type": "timestamp"}]`** (the ONLY
+  globally-sortable field; gates `scan`'s sort at the bifrost dispatch `_validate_scan_sort`
+  AND Worldtree's #349 person-prime Branch-A `"updated_at" in caps.sort_fields_supported` —
+  advertising it is what lights up turn-1 durable-fact injection). Both `name` AND `type`
+  are REQUIRED by the bifrost `handshake_response` `SortableChunkField` schema
+  (`additionalProperties:false`) — omitting `type` fails wire-schema validation and breaks
+  the ENTIRE handshake (memory + affect bind), not just the sort; `type` is advisory-only
+  (the wire never interprets it).
   (`transaction_supported` is the bifrost **wire-level** multi-op transaction
   capability — NOT our internal SQLite transactions, which we use for atomic
   batches.) The client gates the gated verbs off these.
@@ -145,6 +149,20 @@ interpreted.
   `updated_at desc`), matching bifrost's cross-pagination conformance negative. The sort
   field is indexed (`json_extract(record_json, '$.updated_at')`) so the read stays within
   person-prime's 500 ms fail-open budget.
+  - **Cursor is v1-provisional (KNOWN DEVIATION — offset, not snapshot).** The cursor is a
+    bare integer offset into the re-derived global order. This is CORRECT and conformant for
+    the **single-page** person-prime call (`cursor=None`), which is the only shipped consumer.
+    It **diverges from bifrost's protocol snapshot-cursor contract on multi-page continuation**:
+    the dispatch engine (`bifrost.memory` scan branch) drops the `sort` arg on a cursor
+    continuation because "the cursor's snapshotted order is authoritative", and maps
+    `ScanCursorExpired → 410`. Our offset cursor (a) does NOT snapshot the order — a page taken
+    after a concurrent write can duplicate/drop rows relative to the first page (heid-bug-hunt
+    2026-07-15, all 3 arms), and (b) never raises `ScanCursorExpired`. The `global_before_paginate`
+    / cursor test asserts **static-store** behavior only. The durable/conformant fix is to adopt
+    the reference `InMemoryMemoryStore`'s snapshot-cursor semantics (opaque token + frozen ordered
+    id-list + TTL + `ScanCursorExpired`); DEFERRED pending bifrost-dev's ruling on the conformance
+    gap (scan/cursor has NO conformance coverage today, so a non-snapshot cursor passes). Routed
+    to bifrost-dev 2026-07-15.
 
 ## Concurrency
 

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "ratatoskr"
-version = "0.20.12"
+version = "0.20.14"
 description = "Worldtree Conversation API debug TUI — multi-pane observability dashboard"
 readme = "README.md"
 requires-python = ">=3.12"

src/ratatoskr/provider/memory_store.py

@@ -132,7 +132,10 @@ def _validate_injection(record: dict) -> None:
         raise InvalidArguments("injection_source only valid for injected_context origin")
 
 
-_SORTABLE_CHUNK_FIELDS: list[dict] = [{"name": "updated_at"}]
+# bifrost handshake_response SortableChunkField requires BOTH name + type
+# (additionalProperties:false); omitting `type` fails wire-schema validation and
+# breaks the whole handshake. `type` is advisory-only (the wire never interprets it).
+_SORTABLE_CHUNK_FIELDS: list[dict] = [{"name": "updated_at", "type": "timestamp"}]
 _SORTABLE_FIELD_NAMES = frozenset(f["name"] for f in _SORTABLE_CHUNK_FIELDS)
 
 
@@ -383,6 +386,8 @@ class RatatoskrMemoryStore:
         scope_all = scope_all or {}
         scope_any = scope_any or []
         _validate_scope(scope_all, scope_any)  # PRE-002 (same lattice as search)
+        if sort is not None and not isinstance(sort, dict):  # PRE-003: malformed sort => reject, never crash
+            raise InvalidArguments("sort must be an object with field and direction")
         field = (sort or {}).get("field", "updated_at")
         direction = (sort or {}).get("direction", "desc")
         if field not in _SORTABLE_FIELD_NAMES or direction not in ("asc", "desc"):  # PRE-003

tests/test_provider_memory.py

@@ -62,6 +62,15 @@ def test_fresh_db_advertises_v1_caps_and_schema():
     assert caps["atomic_supersede_supported"] is False
     assert caps["transaction_supported"] is False
     assert caps["filterable_metadata_fields"] == []
+    # bifrost handshake_response SortableChunkField requires BOTH name + type
+    # (additionalProperties:false) — omitting `type` fails wire-schema validation and
+    # breaks the ENTIRE Bifrost bind (regression guard: the deploy-breaker of 2026-07-15).
+    scf = caps["sortable_chunk_fields"]
+    assert scf == [{"name": "updated_at", "type": "timestamp"}]
+    for entry in scf:
+        assert set(entry) == {"name", "type"}  # required exactly, no extra keys
+        assert isinstance(entry["name"], str) and entry["name"]
+        assert isinstance(entry["type"], str) and entry["type"]
     # tables + vec index queryable
     store._conn.execute("SELECT * FROM memory_chunks")
     store._conn.execute("SELECT * FROM memory_idempotency")
@@ -427,6 +436,14 @@ async def test_scan_unadvertised_sort_field_rejected():
         await store.scan(scope_all={"end_user": "u1"}, limit=3, sort={"field": "salience", "direction": "desc"})
 
 
+async def test_scan_non_dict_sort_rejected():
+    # PRE-003: a truthy non-dict sort (caller-controlled) -> InvalidArguments, never AttributeError.
+    store = open_memory_store(":memory:", embedding_dim=EMBEDDING_DIM)
+    for bad in ("updated_at", ["updated_at"], 5):
+        with pytest.raises(InvalidArguments):
+            await store.scan(scope_all={"end_user": "u1"}, limit=3, sort=bad)
+
+
 async def test_scan_records_carry_person_prime_filter_fields():
     # The client _scan_filter_matches keys on agent_id + subject + worldtree_scope; a record
     # missing any is silently dropped -> the scan record must carry them verbatim.

uv.lock

@@ -1052,7 +1052,7 @@ wheels = [
 
 [[package]]
 name = "ratatoskr"
-version = "0.20.12"
+version = "0.20.14"
 source = { editable = "." }
 dependencies = [
     { name = "httpx" },