diff --git a/docs/contracts/bifrost_memory_provider.contract.md b/docs/contracts/bifrost_memory_provider.contract.md
index f7d4243..283a60a 100644
--- a/docs/contracts/bifrost_memory_provider.contract.md
+++ b/docs/contracts/bifrost_memory_provider.contract.md
@@ -209,9 +209,10 @@ FN search(self, vector: list[float], *, top_k: int, scope_filter: dict | None =
 BRIEF: Vector (cosine) recall over sqlite-vec, scoped, returning the top_k IN-SCOPE chunks.
 PRE: [PRE-001 hard] len(vector) == embedding_dim -- else InvalidArguments
 PRE: [PRE-002 hard] metadata_filter is empty/None -- v1 advertises no filterable fields; a non-empty filter → InvalidArguments
+PRE: [PRE-003 hard] every scope_filter axis ∈ {end_user, group, tenant, agent_self} -- else InvalidFilter (memory.invalid_filter 400); the bifrost wire-v0.5 lattice, matching the reference _validate_scope_filter (#10 made agent_self canonical)
 POST: [POST-001 return_value] returns the top_k highest-cosine records WHOSE scope matches scope_filter — at most top_k, and never fewer than min(top_k, in-scope count) (INV-005). Each: {chunk (verbatim), chunk_id, score, recalled_view (= chunk["distillate"] or chunk), revision} -- assert
 STEPS:
-  1. [setup] validate scope_filter is a flat {axis: value} dict (matched against record["scope"][axis])
+  1. [setup] validate scope_filter is a flat {axis: value} dict (matched against record["scope"][axis]) AND every axis ∈ the v0.5 lattice {end_user, group, tenant, agent_self} (else InvalidFilter)
   2. [sequential, flexibility=indicative] rank candidates by cosine over record["embedding"]; KEEP only scope-matching records (INV-005); THEN take top_k — so top_k counts IN-SCOPE hits, not pre-filter hits (over-fetch from the vec index or post-filter rank as needed)
   3. [cleanup] RETURN result rows (chunk verbatim + score + recalled_view + revision)
 TESTS:
@@ -219,6 +220,7 @@ TESTS:
   scope_isolation [adversarial]: two scopes, search one → never returns the other's chunk, and returns top_k of the IN-SCOPE set even if out-of-scope chunks score higher (INV-005)
   empty [boundary]: search empty store → []
   metadata_filter_rejected [adversarial]: non-empty metadata_filter → InvalidArguments
+  lattice_axes [adversarial]: out-of-lattice scope axis → InvalidFilter; agent_self admitted (wire v0.5, #10)
   parity_vs_reference [scenario]: identical search envelopes vs InMemoryMemoryStore → same ranked chunk_ids/shape (#195)
 ```
 
diff --git a/pyproject.toml b/pyproject.toml
index 927d374..fe624f5 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "ratatoskr"
-version = "0.17.4"
+version = "0.17.5"
 description = "Worldtree Conversation API debug TUI — multi-pane observability dashboard"
 readme = "README.md"
 requires-python = ">=3.12"
@@ -30,7 +30,7 @@ web = [
 # from the debug TUI. Recipe: bifrost/docs/implementing-a-consumer.md.
 provider = [
     "ratatoskr[web]",       # reuse the starlette + uvicorn ASGI stack
-    "bifrost>=0.6.1",       # consumer engines + library (0.6.0 yanked: circular import)
+    "bifrost>=0.7.0",       # consumer engines + library (0.7.0/wire-v0.5: agent_self canonical in the scope lattice; 0.6.0 yanked: circular import)
     "jsonschema>=4",        # bifrost runtime dep — envelope validation
     "sqlite-vec>=0.1.6",    # vector index for the memory plane (vec0 virtual table)
 ]
diff --git a/src/ratatoskr/provider/memory_store.py b/src/ratatoskr/provider/memory_store.py
index 19a722a..abd5e94 100644
--- a/src/ratatoskr/provider/memory_store.py
+++ b/src/ratatoskr/provider/memory_store.py
@@ -25,6 +25,7 @@ from bifrost.consumer import ConsumerRegistration, build_memory_app
 from bifrost.memory import (
     IdempotencyConflict,
     InvalidArguments,
+    InvalidFilter,
     RevisionMismatch,
     StoreCapabilities,
 )
@@ -33,6 +34,11 @@ from bifrost.reference_server import JwtVerifier
 _SHORT_RETRY_TTL_SECONDS = 300
 _DURABLE_JOB_TTL_SECONDS = 24 * 60 * 60
 
+# bifrost wire v0.5 scope lattice: three subject axes + agent_self (the #248
+# agent-identity axis, made canonical in #10). An axis outside it is InvalidFilter
+# (-> memory.invalid_filter 400), matching bifrost's reference _validate_scope_filter.
+_SCOPE_LATTICE = {"end_user", "group", "tenant", "agent_self"}
+
 # Inbound memory-call observability (#17 observe brick). A self-contained
 # stdout handler so the lines reliably reach the provider's stdout regardless
 # of uvicorn's logging config. INFO-level, no propagation to root.
@@ -205,6 +211,8 @@ class RatatoskrMemoryStore:
             raise InvalidArguments("metadata_filter is unsupported in v1")
         if scope_filter is not None and not isinstance(scope_filter, dict):  # STEP 1
             raise InvalidArguments("scope_filter must be a flat {axis: value} dict")
+        if scope_filter and any(axis not in _SCOPE_LATTICE for axis in scope_filter):
+            raise InvalidFilter("scope_filter contains unsupported axis")
         _log.info(
             "memory-call search REQUEST: scope_filter=%r top_k=%s metadata_filter=%r vec_dim=%d",
             scope_filter, top_k, metadata_filter, len(vector),
diff --git a/tests/test_provider_memory.py b/tests/test_provider_memory.py
index 700d763..d2fc41f 100644
--- a/tests/test_provider_memory.py
+++ b/tests/test_provider_memory.py
@@ -10,7 +10,12 @@ from __future__ import annotations
 import types
 
 import pytest
-from bifrost.memory import IdempotencyConflict, InvalidArguments, RevisionMismatch
+from bifrost.memory import (
+    IdempotencyConflict,
+    InvalidArguments,
+    InvalidFilter,
+    RevisionMismatch,
+)
 
 from ratatoskr.provider.memory_store import (
     build_memory_provider_app,
@@ -221,6 +226,28 @@ async def test_search_non_dict_scope_filter_rejected():
         await store.search(_vec(1.0), top_k=5, scope_filter="u1")
 
 
+async def test_search_out_of_lattice_scope_axis_rejected():
+    # v0.5 scope lattice = {end_user, group, tenant, agent_self}; an axis outside
+    # it is InvalidFilter (-> memory.invalid_filter 400), matching bifrost's reference.
+    store = open_memory_store(":memory:", embedding_dim=EMBEDDING_DIM)
+    with pytest.raises(InvalidFilter):
+        await store.search(_vec(1.0), top_k=5, scope_filter={"bogus_axis": "x"})
+
+
+async def test_search_agent_self_axis_accepted():
+    # agent_self became canonical at wire v0.5 (#10) — admitted, not rejected.
+    store = open_memory_store(":memory:", embedding_dim=EMBEDDING_DIM)
+    await store.upsert_many(
+        [_chunk("a1", scope={"agent_self": "ratatoskr:smoke"})],
+        idempotency_key="k1",
+        ctx=_ctx(),
+    )
+    results = await store.search(
+        _vec(1.0), top_k=5, scope_filter={"agent_self": "ratatoskr:smoke"}
+    )
+    assert [r["chunk_id"] for r in results] == ["a1"]
+
+
 async def test_search_top_k_zero_returns_empty():
     # POST-001: at most top_k — zero means zero
     store = open_memory_store(":memory:", embedding_dim=EMBEDDING_DIM)
diff --git a/uv.lock b/uv.lock
index cf36e1a..be0c621 100644
--- a/uv.lock
+++ b/uv.lock
@@ -190,14 +190,14 @@ wheels = [
 
 [[package]]
 name = "bifrost"
-version = "0.6.1"
+version = "0.7.0"
 source = { registry = "https://gitea.phasefinal.com/api/packages/vh/pypi/simple/" }
 dependencies = [
     { name = "jsonschema" },
 ]
-sdist = { url = "https://gitea.phasefinal.com/api/packages/vh/pypi/files/bifrost/0.6.1/bifrost-0.6.1.tar.gz", hash = "sha256:2eaf93c6da91faa6faa80a4c9a8d0c66161f4a7cc31ff041b0ae64daf3c161ea" }
+sdist = { url = "https://gitea.phasefinal.com/api/packages/vh/pypi/files/bifrost/0.7.0/bifrost-0.7.0.tar.gz", hash = "sha256:27d5c2c3052ad48510a4a73973141f2177b9e1f66576ab3d8976d5c4deb5bfac" }
 wheels = [
-    { url = "https://gitea.phasefinal.com/api/packages/vh/pypi/files/bifrost/0.6.1/bifrost-0.6.1-py3-none-any.whl", hash = "sha256:ed505d2c08cf4cdd0a84c68ec42f8732b4c1baf7d72befe5eacf75d88381d5ce" },
+    { url = "https://gitea.phasefinal.com/api/packages/vh/pypi/files/bifrost/0.7.0/bifrost-0.7.0-py3-none-any.whl", hash = "sha256:9704c50430f350f6dde5428f79a8719e044021ce717a5eac60a13424b1ee4623" },
 ]
 
 [[package]]
@@ -1052,7 +1052,7 @@ wheels = [
 
 [[package]]
 name = "ratatoskr"
-version = "0.17.4"
+version = "0.17.5"
 source = { editable = "." }
 dependencies = [
     { name = "httpx" },
@@ -1086,7 +1086,7 @@ web = [
 
 [package.metadata]
 requires-dist = [
-    { name = "bifrost", marker = "extra == 'provider'", specifier = ">=0.6.1", index = "https://gitea.phasefinal.com/api/packages/vh/pypi/simple/" },
+    { name = "bifrost", marker = "extra == 'provider'", specifier = ">=0.7.0", index = "https://gitea.phasefinal.com/api/packages/vh/pypi/simple/" },
     { name = "httpx", specifier = ">=0.27" },
     { name = "httpx-sse", specifier = ">=0.4" },
     { name = "jsonschema", marker = "extra == 'provider'", specifier = ">=4" },