fix(agent): repair mcp_ prefix drop in _repair_tool_call

run_agent.py

@@ -5629,6 +5629,22 @@ def _strip_tool_suffix(s: str) -> str | None:
         if normalized in self.valid_tool_names:
             return normalized
 
+        # MCP prefix-strip: models sometimes drop the ``mcp_`` prefix that
+        # Hermes prepends when registering MCP server tools, e.g. calling
+        # ``APE_search`` instead of ``mcp_APE_search``.  A direct prepend
+        # check is unambiguous — only resolves when there's an exact match.
+        # (difflib scores ~0.60 for this pattern, just under the 0.7 cutoff.)
+        for prefix_candidate in (f"mcp_{tool_name}", f"mcp_{lowered}", f"mcp_{normalized}"):
+            if prefix_candidate in self.valid_tool_names:
+                return prefix_candidate
+        # Also try mcp_ + each valid name stripped of its prefix, case-folded.
+        # Handles APE_SEARCH -> mcp_APE_search when the registered name has
+        # mixed case after the server component.
+        lowered_with_prefix = f"mcp_{lowered}"
+        for vname in self.valid_tool_names:
+            if vname.lower() == lowered_with_prefix:
+                return vname
+
         # Build the full candidate set for class-like emissions.
         cands: set[str] = {tool_name, lowered, normalized, _camel_snake(tool_name)}
         # Strip trailing tool-suffix up to twice — TodoTool_tool needs it.

tests/run_agent/test_repair_tool_call_name.py

@@ -115,3 +115,68 @@ def test_none_passed_as_name(self, repair):
     def test_very_long_name_does_not_match_by_accident(self, repair):
         # Fuzzy match should not claim a tool for something obviously unrelated.
         assert repair("ThisIsNotRemotelyARealToolName_tool") is None
+
+
+MCP_VALID = {
+    "mcp_APE_meta",
+    "mcp_APE_search",
+    "mcp_APE_add",
+    "mcp_APE_contextualize",
+    "mcp_APE_graph_nearby",
+    "mcp_APE_graph_connect",
+    "mcp_discord_send",
+    "terminal",
+    "read_file",
+}
+
+
+@pytest.fixture
+def mcp_repair():
+    """Repair fixture with MCP-prefixed tool names registered."""
+    from run_agent import AIAgent
+    stub = SimpleNamespace(valid_tool_names=MCP_VALID)
+    return AIAgent._repair_tool_call.__get__(stub, AIAgent)
+
+
+class TestMcpPrefixDrop:
+    """Regression guard: models drop the ``mcp_`` prefix Hermes adds when
+    registering MCP server tools (e.g. ``APE_search`` instead of
+    ``mcp_APE_search``).  difflib scores ~0.60 for this pattern — just
+    below the 0.7 cutoff — so the fuzzy path misses it.  The explicit
+    prefix-prepend check introduced alongside these tests catches it."""
+
+    def test_ape_meta_without_prefix(self, mcp_repair):
+        assert mcp_repair("APE_meta") == "mcp_APE_meta"
+
+    def test_ape_search_without_prefix(self, mcp_repair):
+        assert mcp_repair("APE_search") == "mcp_APE_search"
+
+    def test_ape_add_without_prefix(self, mcp_repair):
+        assert mcp_repair("APE_add") == "mcp_APE_add"
+
+    def test_ape_contextualize_without_prefix(self, mcp_repair):
+        assert mcp_repair("APE_contextualize") == "mcp_APE_contextualize"
+
+    def test_ape_graph_nearby_without_prefix(self, mcp_repair):
+        assert mcp_repair("APE_graph_nearby") == "mcp_APE_graph_nearby"
+
+    def test_other_mcp_server_without_prefix(self, mcp_repair):
+        # Not APE-specific — any mcp_<server>_<tool> pattern should resolve.
+        assert mcp_repair("discord_send") == "mcp_discord_send"
+
+    def test_already_correct_name_unchanged(self, mcp_repair):
+        # Already has prefix — fast-path returns it directly, no double-prefix.
+        assert mcp_repair("mcp_APE_meta") == "mcp_APE_meta"
+
+    def test_uppercase_without_prefix(self, mcp_repair):
+        # Case-insensitive: APE_SEARCH -> mcp_APE_search via lowered candidate.
+        assert mcp_repair("APE_SEARCH") == "mcp_APE_search"
+
+    def test_non_mcp_tool_unaffected(self, mcp_repair):
+        # Non-MCP tools in the valid set must still resolve normally.
+        assert mcp_repair("TERMINAL") == "terminal"
+
+    def test_prefix_drop_does_not_invent_tools(self, mcp_repair):
+        # Prepending mcp_ to a non-existent name must not return a wrong match.
+        assert mcp_repair("APE_nonexistent") is None
+