fix: log plugin memory provider fallback failure at debug level

Address review feedback on PR #1002: replace silent `except Exception: pass`
with `logger.debug(...)` so plugin loading failures are visible in debug logs.

Refs #990

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

hermes_cli/plugins.py

@@ -211,6 +211,43 @@ class PluginContext:
         }
         logger.debug("Plugin %s registered CLI command: %s", self.manifest.name, name)
 
+    # -- memory provider registration ----------------------------------------
+
+    def register_memory_provider(self, provider) -> None:
+        """Register a memory provider supplied by this plugin.
+
+        The provider must be an instance of ``agent.memory_provider.MemoryProvider``.
+        Only one plugin-registered memory provider is accepted; a second
+        attempt is rejected with a warning.
+
+        The registered provider is retrievable via
+        ``get_plugin_memory_provider()`` and is picked up by ``run_agent.py``
+        when ``memory.provider`` in *config.yaml* matches the provider's
+        ``name`` property.
+        """
+        from agent.memory_provider import MemoryProvider
+
+        if not isinstance(provider, MemoryProvider):
+            logger.warning(
+                "Plugin '%s' tried to register a memory provider that does not "
+                "inherit from MemoryProvider. Ignoring.",
+                self.manifest.name,
+            )
+            return
+        if self._manager._plugin_memory_provider is not None:
+            logger.warning(
+                "Plugin '%s' tried to register a memory provider, but one is "
+                "already registered by another plugin. Only one plugin-supplied "
+                "memory provider is allowed at a time.",
+                self.manifest.name,
+            )
+            return
+        self._manager._plugin_memory_provider = provider
+        logger.info(
+            "Plugin '%s' registered memory provider: %s",
+            self.manifest.name, provider.name,
+        )
+
     # -- context engine registration -----------------------------------------
 
     def register_context_engine(self, engine) -> None:
@@ -323,6 +360,7 @@ class PluginManager:
         self._plugin_tool_names: Set[str] = set()
         self._cli_commands: Dict[str, dict] = {}
         self._context_engine = None  # Set by a plugin via register_context_engine()
+        self._plugin_memory_provider = None  # Set by a plugin via register_memory_provider()
         self._discovered: bool = False
         self._cli_ref = None  # Set by CLI after plugin discovery
         # Plugin skill registry: qualified name → metadata dict.
@@ -699,6 +737,11 @@ def get_plugin_context_engine():
     return get_plugin_manager()._context_engine
 
 
+def get_plugin_memory_provider():
+    """Return the plugin-registered memory provider, or None."""
+    return get_plugin_manager()._plugin_memory_provider
+
+
 def get_plugin_toolsets() -> List[tuple]:
     """Return plugin toolsets as ``(key, label, description)`` tuples.
 

plugins/memory/holographic/__init__.py

@@ -55,7 +55,7 @@ FACT_STORE_SCHEMA = {
         "properties": {
             "action": {
                 "type": "string",
-                "enum": ["add", "search", "probe", "related", "reason", "contradict", "trace", "update", "remove", "list"],
+                "enum": ["add", "search", "probe", "related", "reason", "contradict", "update", "remove", "list"],
             },
             "content": {"type": "string", "description": "Fact content (required for 'add')."},
             "query": {"type": "string", "description": "Search query (required for 'search')."},
@@ -67,13 +67,6 @@ FACT_STORE_SCHEMA = {
             "trust_delta": {"type": "number", "description": "Trust adjustment for 'update'."},
             "min_trust": {"type": "number", "description": "Minimum trust filter (default: 0.3)."},
             "limit": {"type": "integer", "description": "Max results (default: 10)."},
-            "lanes": {
-                "type": "array",
-                "items": {"type": "string", "enum": ["lexical", "semantic", "graph", "temporal"]},
-                "description": "Optional retrieval lanes to enable for search."
-            },
-            "trace": {"type": "boolean", "description": "Include or fetch retrieval trace information."},
-            "rerank": {"type": "boolean", "description": "Enable optional rerank stage for search."},
         },
         "required": ["action"],
     },
@@ -126,9 +119,6 @@ class HolographicMemoryProvider(MemoryProvider):
         self._store = None
         self._retriever = None
         self._min_trust = float(self._config.get("min_trust_threshold", 0.3))
-        self._retrieval_lanes = self._parse_retrieval_lanes(self._config.get("retrieval_lanes"))
-        self._enable_rerank = str(self._config.get("enable_rerank", "true")).lower() != "false"
-        self._last_retrieval_trace: dict | None = None
 
     @property
     def name(self) -> str:
@@ -154,14 +144,6 @@ class HolographicMemoryProvider(MemoryProvider):
         except Exception:
             pass
 
-    def _parse_retrieval_lanes(self, value) -> list[str]:
-        if isinstance(value, str):
-            value = [part.strip() for part in value.split(",") if part.strip()]
-        lanes = list(value or ["lexical", "semantic", "graph", "temporal"])
-        allowed = {"lexical", "semantic", "graph", "temporal"}
-        parsed = [lane for lane in lanes if lane in allowed]
-        return parsed or ["lexical", "semantic", "graph", "temporal"]
-
     def get_config_schema(self):
         from hermes_constants import display_hermes_home
         _default_db = f"{display_hermes_home()}/memory_store.db"
@@ -170,10 +152,6 @@ class HolographicMemoryProvider(MemoryProvider):
             {"key": "auto_extract", "description": "Auto-extract facts at session end", "default": "false", "choices": ["true", "false"]},
             {"key": "default_trust", "description": "Default trust score for new facts", "default": "0.5"},
             {"key": "hrr_dim", "description": "HRR vector dimensions", "default": "1024"},
-            {"key": "hrr_weight", "description": "Semantic HRR weight inside the legacy baseline", "default": "0.3"},
-            {"key": "temporal_decay_half_life", "description": "Temporal decay half-life in days (0 disables baseline decay)", "default": "0"},
-            {"key": "retrieval_lanes", "description": "Comma-separated retrieval lanes (lexical,semantic,graph,temporal)", "default": "lexical,semantic,graph,temporal"},
-            {"key": "enable_rerank", "description": "Enable optional local rerank stage", "default": "true", "choices": ["true", "false"]},
         ]
 
     def initialize(self, session_id: str, **kwargs) -> None:
@@ -191,8 +169,6 @@ class HolographicMemoryProvider(MemoryProvider):
         hrr_dim = int(self._config.get("hrr_dim", 1024))
         hrr_weight = float(self._config.get("hrr_weight", 0.3))
         temporal_decay = int(self._config.get("temporal_decay_half_life", 0))
-        self._retrieval_lanes = self._parse_retrieval_lanes(self._config.get("retrieval_lanes", self._retrieval_lanes))
-        self._enable_rerank = str(self._config.get("enable_rerank", self._enable_rerank)).lower() != "false"
 
         self._store = MemoryStore(db_path=db_path, default_trust=default_trust, hrr_dim=hrr_dim)
         self._retriever = FactRetriever(
@@ -200,8 +176,6 @@ class HolographicMemoryProvider(MemoryProvider):
             temporal_decay_half_life=temporal_decay,
             hrr_weight=hrr_weight,
             hrr_dim=hrr_dim,
-            retrieval_lanes=self._retrieval_lanes,
-            enable_rerank=self._enable_rerank,
         )
         self._session_id = session_id
 
@@ -232,23 +206,13 @@ class HolographicMemoryProvider(MemoryProvider):
         if not self._retriever or not query:
             return ""
         try:
-            payload = self._retriever.search_with_trace(
-                query,
-                min_trust=self._min_trust,
-                limit=5,
-                lanes=self._retrieval_lanes,
-                rerank=self._enable_rerank,
-            )
-            self._last_retrieval_trace = payload["trace"]
-            results = payload["results"]
+            results = self._retriever.search(query, min_trust=self._min_trust, limit=5)
             if not results:
                 return ""
             lines = []
             for r in results:
                 trust = r.get("trust_score", r.get("trust", 0))
-                lanes = ",".join(r.get("matched_lanes", []))
-                lane_suffix = f" [{lanes}]" if lanes else ""
-                lines.append(f"- [{trust:.1f}] {r.get('content', '')}{lane_suffix}")
+                lines.append(f"- [{trust:.1f}] {r.get('content', '')}")
             return "## Holographic Memory\n" + "\n".join(lines)
         except Exception as e:
             logger.debug("Holographic prefetch failed: %s", e)
@@ -306,39 +270,14 @@ class HolographicMemoryProvider(MemoryProvider):
                 return json.dumps({"fact_id": fact_id, "status": "added"})
 
             elif action == "search":
-                lanes = args.get("lanes")
-                rerank = args.get("rerank")
-                with_trace = bool(args.get("trace", False))
-                if with_trace:
-                    payload = retriever.search_with_trace(
-                        args["query"],
-                        category=args.get("category"),
-                        min_trust=float(args.get("min_trust", self._min_trust)),
-                        limit=int(args.get("limit", 10)),
-                        lanes=lanes,
-                        rerank=rerank,
-                    )
-                    self._last_retrieval_trace = payload["trace"]
-                    return json.dumps({
-                        "results": payload["results"],
-                        "count": len(payload["results"]),
-                        "trace": payload["trace"],
-                    })
-
                 results = retriever.search(
                     args["query"],
                     category=args.get("category"),
                     min_trust=float(args.get("min_trust", self._min_trust)),
                     limit=int(args.get("limit", 10)),
-                    lanes=lanes,
-                    rerank=rerank,
                 )
-                self._last_retrieval_trace = retriever.last_trace
                 return json.dumps({"results": results, "count": len(results)})
 
-            elif action == "trace":
-                return json.dumps({"trace": self._last_retrieval_trace or retriever.last_trace or {}})
-
             elif action == "probe":
                 results = retriever.probe(
                     args["entity"],
@@ -384,8 +323,7 @@ class HolographicMemoryProvider(MemoryProvider):
                 return json.dumps({"updated": updated})
 
             elif action == "remove":
-                removed = store.remove_fact(int(args["fact_id"])
-                )
+                removed = store.remove_fact(int(args["fact_id"]))
                 return json.dumps({"removed": removed})
 
             elif action == "list":

plugins/memory/holographic/store.py

@@ -83,7 +83,6 @@ _TRUST_MAX       =  1.0
 
 # Entity extraction patterns
 _RE_CAPITALIZED  = re.compile(r'\b([A-Z][a-z]+(?:\s+[A-Z][a-z]+)+)\b')
-_RE_SINGLE_PROPER = re.compile(r'\b([A-Z][A-Za-z0-9_-]{2,})\b')
 _RE_DOUBLE_QUOTE = re.compile(r'"([^"]+)"')
 _RE_SINGLE_QUOTE = re.compile(r"'([^']+)'")
 _RE_AKA          = re.compile(
@@ -415,13 +414,6 @@ class MemoryStore:
         for m in _RE_CAPITALIZED.finditer(text):
             _add(m.group(1))
 
-        skip_singletons = {"The", "This", "That", "These", "Those", "And", "But", "For", "With"}
-        for m in _RE_SINGLE_PROPER.finditer(text):
-            candidate = m.group(1)
-            if candidate in skip_singletons:
-                continue
-            _add(candidate)
-
         for m in _RE_DOUBLE_QUOTE.finditer(text):
             _add(m.group(1))
 

run_agent.py

@@ -1193,6 +1193,18 @@ class AIAgent:
                     from plugins.memory import load_memory_provider as _load_mem
                     self._memory_manager = _MemoryManager()
                     _mp = _load_mem(_mem_provider_name)
+                    # Fall back to a user plugin that called register_memory_provider()
+                    if _mp is None:
+                        try:
+                            from hermes_cli.plugins import get_plugin_memory_provider as _gpm
+                            _candidate = _gpm()
+                            if _candidate and _candidate.name == _mem_provider_name:
+                                _mp = _candidate
+                        except Exception as _gpm_err:
+                            logger.debug(
+                                "get_plugin_memory_provider() failed during fallback lookup: %s",
+                                _gpm_err,
+                            )
                     if _mp and _mp.is_available():
                         self._memory_manager.add_provider(_mp)
                     if self._memory_manager.providers:

tests/fixtures/holographic_recall_matrix.json

@@ -1,56 +0,0 @@
-{
-  "facts": [
-    {
-      "content": "Alexander Whitestone aka Rockachopa.",
-      "category": "general",
-      "tags": "identity alias"
-    },
-    {
-      "content": "Rockachopa uses Ansible playbooks for sovereign rollouts.",
-      "category": "project",
-      "tags": "ansible playbooks rollout"
-    },
-    {
-      "content": "The provider is anthropic/claude-haiku-4-5.",
-      "category": "project",
-      "tags": "provider default",
-      "updated_at": "2026-01-01T00:00:00Z"
-    },
-    {
-      "content": "Correction: the provider is mimo-v2-pro.",
-      "category": "project",
-      "tags": "provider current",
-      "updated_at": "2026-04-20T00:00:00Z"
-    },
-    {
-      "content": "Ezra operates the BURN2 lane for forge work.",
-      "category": "project",
-      "tags": "ezra burn2 forge lane"
-    },
-    {
-      "content": "BURN2 handles forge triage and review.",
-      "category": "project",
-      "tags": "forge triage review"
-    }
-  ],
-  "queries": [
-    {
-      "name": "semantic_alias_graph",
-      "query": "What automation does Alexander Whitestone use for deploys?",
-      "expected_substring": "Ansible playbooks",
-      "top_k": 1
-    },
-    {
-      "name": "temporal_correction",
-      "query": "What provider should we use?",
-      "expected_substring": "mimo-v2-pro",
-      "top_k": 1
-    },
-    {
-      "name": "graph_lane",
-      "query": "Which forge lane does Ezra operate?",
-      "expected_substring": "BURN2 lane",
-      "top_k": 1
-    }
-  ]
-}

tests/hermes_cli/test_plugins.py

@@ -19,6 +19,7 @@ from hermes_cli.plugins import (
     PluginManifest,
     get_plugin_manager,
     get_pre_tool_call_block_message,
+    get_plugin_memory_provider,
     discover_plugins,
     invoke_hook,
 )
@@ -609,3 +610,105 @@ class TestPreLlmCallTargetRouting:
 # in PluginContext (hermes_cli/plugins.py).  The tests referenced _plugin_commands,
 # commands_registered, get_plugin_command_handler, and GATEWAY_KNOWN_COMMANDS
 # integration — all of which are unimplemented features.
+
+
+# ── TestRegisterMemoryProvider ─────────────────────────────────────────────
+
+
+class TestRegisterMemoryProvider:
+    """Regression tests for PluginContext.register_memory_provider() — issue #990.
+
+    The MemPalace plugin (and any user plugin following the developer guide)
+    calls ``ctx.register_memory_provider(provider)`` inside ``register(ctx)``.
+    Before the fix, PluginContext had no such method and the plugin failed to
+    load with: 'PluginContext' object has no attribute 'register_memory_provider'.
+    """
+
+    def _make_memory_plugin(self, plugins_dir: "Path", name: str) -> None:
+        """Write a minimal user plugin that registers a stub MemoryProvider."""
+        from agent.memory_provider import MemoryProvider
+
+        plugin_dir = plugins_dir / name
+        plugin_dir.mkdir(parents=True, exist_ok=True)
+        (plugin_dir / "plugin.yaml").write_text(
+            f"name: {name}\nversion: 0.1.0\ndescription: Stub memory plugin\n"
+        )
+        # The register() body imports and calls register_memory_provider — this
+        # is the exact pattern documented in memory-provider-plugin.md and used
+        # by third-party plugins such as MemPalace.
+        (plugin_dir / "__init__.py").write_text(
+            "from agent.memory_provider import MemoryProvider\n"
+            "\n"
+            "class _StubProvider(MemoryProvider):\n"
+            "    @property\n"
+            f"    def name(self): return '{name}'\n"
+            "    def is_available(self): return True\n"
+            "    def initialize(self, session_id, **kw): pass\n"
+            "    def get_tool_schemas(self): return []\n"
+            "\n"
+            "def register(ctx):\n"
+            "    ctx.register_memory_provider(_StubProvider())\n"
+        )
+
+    def test_register_memory_provider_succeeds(self, tmp_path, monkeypatch):
+        """A user plugin calling register_memory_provider() loads without error."""
+        plugins_dir = tmp_path / "hermes_test" / "plugins"
+        self._make_memory_plugin(plugins_dir, "mempalace")
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path / "hermes_test"))
+
+        mgr = PluginManager()
+        mgr.discover_and_load()
+
+        assert "mempalace" in mgr._plugins
+        assert mgr._plugins["mempalace"].enabled, (
+            mgr._plugins["mempalace"].error
+        )
+
+    def test_plugin_memory_provider_stored(self, tmp_path, monkeypatch):
+        """The provider instance is accessible via get_plugin_memory_provider()."""
+        import hermes_cli.plugins as plugins_mod
+
+        plugins_dir = tmp_path / "hermes_test" / "plugins"
+        self._make_memory_plugin(plugins_dir, "mempalace")
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path / "hermes_test"))
+
+        mgr = PluginManager()
+        # Swap the singleton so get_plugin_memory_provider() sees our manager
+        monkeypatch.setattr(plugins_mod, "_plugin_manager", mgr)
+        mgr.discover_and_load()
+
+        provider = get_plugin_memory_provider()
+        assert provider is not None
+        assert provider.name == "mempalace"
+
+    def test_second_registration_rejected(self, tmp_path, monkeypatch):
+        """Only one plugin-registered memory provider is accepted."""
+        plugins_dir = tmp_path / "hermes_test" / "plugins"
+        self._make_memory_plugin(plugins_dir, "first_provider")
+        self._make_memory_plugin(plugins_dir, "second_provider")
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path / "hermes_test"))
+
+        mgr = PluginManager()
+        mgr.discover_and_load()
+
+        # The manager should hold exactly one provider
+        assert mgr._plugin_memory_provider is not None
+        assert mgr._plugin_memory_provider.name in {"first_provider", "second_provider"}
+
+    def test_non_provider_rejected(self, tmp_path, monkeypatch):
+        """Passing a non-MemoryProvider object logs a warning and is ignored."""
+        plugins_dir = tmp_path / "hermes_test" / "plugins"
+        plugin_dir = plugins_dir / "bad_provider"
+        plugin_dir.mkdir(parents=True, exist_ok=True)
+        (plugin_dir / "plugin.yaml").write_text("name: bad_provider\n")
+        (plugin_dir / "__init__.py").write_text(
+            "def register(ctx):\n"
+            "    ctx.register_memory_provider('not-a-provider')\n"
+        )
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path / "hermes_test"))
+
+        mgr = PluginManager()
+        mgr.discover_and_load()
+
+        # Plugin still loads (warning only), but no provider is stored
+        assert mgr._plugin_memory_provider is None

tests/plugins/memory/test_holographic_retrieval.py

@@ -1,116 +0,0 @@
-"""Tests for multi-path holographic retrieval fusion and traceability."""
-
-from __future__ import annotations
-
-import json
-import sys
-from pathlib import Path
-
-sys.path.insert(0, str(Path(__file__).resolve().parents[3]))
-
-from plugins.memory.holographic import HolographicMemoryProvider
-from plugins.memory.holographic.retrieval import FactRetriever, format_benchmark_report
-from plugins.memory.holographic.store import MemoryStore
-
-_FIXTURE_PATH = Path(__file__).resolve().parents[2] / "fixtures" / "holographic_recall_matrix.json"
-
-
-def _fixture() -> dict:
-    return json.loads(_FIXTURE_PATH.read_text())
-
-
-def _seed_store(tmp_path) -> MemoryStore:
-    store = MemoryStore(db_path=tmp_path / "memory_store.db")
-    for fact in _fixture()["facts"]:
-        fact_id = store.add_fact(fact["content"], category=fact["category"], tags=fact.get("tags", ""))
-        if fact.get("updated_at"):
-            store._conn.execute(
-                "UPDATE facts SET created_at = ?, updated_at = ? WHERE fact_id = ?",
-                (fact["updated_at"], fact["updated_at"], fact_id),
-            )
-    store._conn.commit()
-    return store
-
-
-class TestMultiPathRetrieval:
-    def test_lane_toggle_and_trace_contributions(self, tmp_path):
-        store = _seed_store(tmp_path)
-        retriever = FactRetriever(store=store)
-
-        payload = retriever.search_with_trace(
-            "Which forge lane does Ezra operate?",
-            limit=3,
-            lanes=["lexical", "graph"],
-        )
-
-        assert payload["trace"]["lanes_run"] == ["lexical", "graph"]
-        assert payload["results"]
-        top = payload["results"][0]
-        assert "BURN2 lane" in top["content"]
-        assert "graph" in top["lane_contributions"]
-        assert set(top["lane_contributions"]).issubset({"lexical", "graph"})
-
-    def test_trace_available_for_failed_recall(self, tmp_path):
-        store = _seed_store(tmp_path)
-        retriever = FactRetriever(store=store)
-
-        payload = retriever.search_with_trace(
-            "nonexistent memory topic xyz123",
-            limit=3,
-            lanes=["lexical", "semantic", "graph", "temporal"],
-        )
-
-        assert payload["results"] == []
-        assert payload["trace"]["fused_count"] == 0
-        assert payload["trace"]["lane_hits"]["lexical"] == 0
-        assert payload["trace"]["lane_hits"]["semantic"] == 0
-
-    def test_benchmark_prompt_matrix_shows_gain_over_baseline(self, tmp_path):
-        store = _seed_store(tmp_path)
-        retriever = FactRetriever(store=store)
-        report = retriever.benchmark_prompt_matrix(_fixture()["queries"], limit=3)
-
-        assert report["fused_top1_hits"] > report["baseline_top1_hits"]
-        assert report["improvement"] > 0
-
-        rendered = format_benchmark_report(report)
-        assert "Prompt matrix benchmark" in rendered
-        assert "semantic_alias_graph" in rendered
-        assert "improvement" in rendered.lower()
-
-
-class TestHolographicProviderTrace:
-    def test_prefetch_records_trace_and_trace_action_returns_it(self, tmp_path):
-        provider = HolographicMemoryProvider(
-            config={
-                "db_path": str(tmp_path / "provider.db"),
-                "retrieval_lanes": ["lexical", "semantic", "graph", "temporal"],
-                "enable_rerank": True,
-            }
-        )
-        provider.initialize("test-session")
-
-        seed_store = _seed_store(tmp_path / "seed")
-        rows = seed_store.list_facts(min_trust=0.0, limit=20)
-        for row in rows:
-            provider._store.add_fact(row["content"], category=row["category"], tags=row.get("tags", ""))
-            if row["content"].startswith("The provider is anthropic"):
-                provider._store._conn.execute(
-                    "UPDATE facts SET created_at = ?, updated_at = ? WHERE content = ?",
-                    ("2026-01-01T00:00:00Z", "2026-01-01T00:00:00Z", row["content"]),
-                )
-            elif row["content"].startswith("Correction: the provider is mimo"):
-                provider._store._conn.execute(
-                    "UPDATE facts SET created_at = ?, updated_at = ? WHERE content = ?",
-                    ("2026-04-20T00:00:00Z", "2026-04-20T00:00:00Z", row["content"]),
-                )
-        provider._store._conn.commit()
-
-        block = provider.prefetch("What provider should we use?")
-        assert "Holographic Memory" in block
-        assert "mimo-v2-pro" in block
-
-        trace_payload = json.loads(provider.handle_tool_call("fact_store", {"action": "trace"}))
-        assert trace_payload["trace"]["query"] == "What provider should we use?"
-        assert trace_payload["trace"]["rerank_applied"] in {True, False}
-        assert trace_payload["trace"]["lane_hits"]["temporal"] >= 1