fix(R7/R9): overlap-density ranking + project trust-preservation

R7: ranking scorer now uses overlap-density (overlap_count /
memory_token_count) as primary key instead of raw overlap count.
A 5-token memory with 3 overlapping tokens (density 0.6) now beats
a 40-token overview memory with 3 overlapping tokens (density 0.075)
at the same absolute count. Secondary: absolute overlap. Tertiary:
confidence. Targeting p06-firmware-interface harness fixture.

R9: when the LLM extractor returns a project that differs from the
interaction's known project, it now checks the project registry.
If the model's project is a registered canonical ID, trust it. If
not (hallucinated name), fall back to the interaction's project.
Uses load_project_registry() for the check. The host-side script
mirrors this via an API call to GET /projects at startup.

Two new tests: test_parser_keeps_registered_model_project and
test_parser_rejects_hallucinated_project.

Test count: 280 -> 281.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

scripts/batch_llm_extract_live.py

@@ -100,6 +100,22 @@ def set_last_run(base_url, timestamp):
         pass
 
 
+_known_projects: set[str] = set()
+
+
+def _load_known_projects(base_url):
+    """Fetch registered project IDs from the API for R9 validation."""
+    global _known_projects
+    try:
+        data = api_get(base_url, "/projects")
+        _known_projects = {p["id"] for p in data.get("projects", [])}
+        for p in data.get("projects", []):
+            for alias in p.get("aliases", []):
+                _known_projects.add(alias)
+    except Exception:
+        pass
+
+
 def extract_one(prompt, response, project, model, timeout_s):
     """Run claude -p on one interaction, return parsed candidates."""
     if not shutil.which("claude"):
@@ -178,6 +194,12 @@ def parse_candidates(raw, interaction_project):
         project = str(item.get("project") or "").strip()
         if not project and interaction_project:
             project = interaction_project
+        elif project and interaction_project and project != interaction_project:
+            # R9: model hallucinated an unrecognized project — fall back.
+            # The host-side script can't import the registry, so we
+            # check against a known set fetched from the API.
+            if project not in _known_projects:
+                project = interaction_project
         conf = item.get("confidence", 0.5)
         if mem_type not in MEMORY_TYPES or not content:
             continue
@@ -202,8 +224,9 @@ def main():
     parser.add_argument("--model", default=DEFAULT_MODEL)
     args = parser.parse_args()
 
+    _load_known_projects(args.base_url)
     since = args.since or get_last_run(args.base_url)
-    print(f"since={since or '(first run)'}  limit={args.limit}  model={args.model}")
+    print(f"since={since or '(first run)'}  limit={args.limit}  model={args.model}  known_projects={len(_known_projects)}")
 
     params = [f"limit={args.limit}"]
     if since:

src/atocore/memory/extractor_llm.py

@@ -257,6 +257,27 @@ def _parse_candidates(raw_output: str, interaction: Interaction) -> list[MemoryC
         project = str(item.get("project") or "").strip()
         if not project and interaction.project:
             project = interaction.project
+        elif project and interaction.project and project != interaction.project:
+            # R9: model returned a different project than the interaction's
+            # known scope. Trust the model's project only if it resolves
+            # to a known registered project (the registry normalizes
+            # aliases and returns the canonical id). If the model
+            # hallucinated an unregistered project name, fall back to
+            # the interaction's known project.
+            try:
+                from atocore.projects.registry import (
+                    load_project_registry,
+                    resolve_project_name,
+                )
+
+                registered_ids = {p.project_id for p in load_project_registry()}
+                resolved = resolve_project_name(project)
+                if resolved not in registered_ids:
+                    project = interaction.project
+                else:
+                    project = resolved
+            except Exception:
+                project = interaction.project
         confidence_raw = item.get("confidence", 0.5)
         if mem_type not in MEMORY_TYPES:
             continue

src/atocore/memory/service.py

@@ -446,20 +446,27 @@ def _rank_memories_for_query(
 ) -> list["Memory"]:
     """Rerank a memory list by lexical overlap with a pre-tokenized query.
 
-    Ordering key: (overlap_count DESC, confidence DESC). When a query
-    shares no tokens with a memory, overlap is zero and confidence
-    acts as the sole tiebreaker — which matches the pre-query
-    behaviour and keeps no-query calls stable.
+    Primary key: overlap_density (overlap_count / memory_token_count),
+    which rewards short focused memories that match the query precisely
+    over long overview memories that incidentally share a few tokens.
+    Secondary: absolute overlap count. Tertiary: confidence.
+
+    R7 fix: previously overlap_count alone was the primary key, so a
+    40-token overview memory with 3 overlapping tokens tied a 5-token
+    memory with 3 overlapping tokens, and the overview won on
+    confidence. Now the short memory's density (0.6) beats the
+    overview's density (0.075).
     """
     from atocore.memory.reinforcement import _normalize, _tokenize
 
-    scored: list[tuple[int, float, Memory]] = []
+    scored: list[tuple[float, int, float, Memory]] = []
     for mem in memories:
         mem_tokens = _tokenize(_normalize(mem.content))
         overlap = len(mem_tokens & query_tokens) if mem_tokens else 0
-        scored.append((overlap, mem.confidence, mem))
-    scored.sort(key=lambda t: (t[0], t[1]), reverse=True)
-    return [mem for _, _, mem in scored]
+        density = overlap / len(mem_tokens) if mem_tokens else 0.0
+        scored.append((density, overlap, mem.confidence, mem))
+    scored.sort(key=lambda t: (t[0], t[1], t[2]), reverse=True)
+    return [mem for _, _, _, mem in scored]
 
 
 def _row_to_memory(row) -> Memory:

tests/test_extractor_llm.py

@@ -107,8 +107,11 @@ def test_parser_falls_back_to_interaction_project():
     assert result[0].project == "p06-polisher"
 
 
-def test_parser_keeps_model_project_when_provided():
-    """Model-supplied project takes precedence over interaction."""
+def test_parser_keeps_registered_model_project(tmp_data_dir, project_registry):
+    """R9: model-supplied project is kept when it's a registered project."""
+    from atocore.models.database import init_db
+    init_db()
+    project_registry(("p04-gigabit", ["p04", "gigabit"]), ("p06-polisher", ["p06"]))
     raw = '[{"type": "project", "content": "x", "project": "p04-gigabit"}]'
     interaction = _make_interaction()
     interaction.project = "p06-polisher"
@@ -116,6 +119,19 @@ def test_parser_keeps_model_project_when_provided():
     assert result[0].project == "p04-gigabit"
 
 
+def test_parser_rejects_hallucinated_project(tmp_data_dir, project_registry):
+    """R9: model-supplied project that is NOT registered falls back
+    to the interaction's known project."""
+    from atocore.models.database import init_db
+    init_db()
+    project_registry(("p06-polisher", ["p06"]))
+    raw = '[{"type": "project", "content": "x", "project": "fake-project-99"}]'
+    interaction = _make_interaction()
+    interaction.project = "p06-polisher"
+    result = _parse_candidates(raw, interaction)
+    assert result[0].project == "p06-polisher"
+
+
 def test_missing_cli_returns_empty(monkeypatch):
     """If ``claude`` is not on PATH the extractor returns empty, never raises."""
     monkeypatch.setattr(extractor_llm, "_cli_available", lambda: False)