fix(tools): preserve MCP server-side tool name after rename

mellea/stdlib/tools/mcp.py

@@ -57,6 +57,12 @@ class MCPToolSpec:
     Holds everything needed to inspect or instantiate a `MelleaTool` without
     keeping a live session open.
 
+    Reassign `name` and `description` before calling `as_mellea_tool` to
+    disambiguate tools that share a name across multiple servers, or to give the
+    model better selection hints. Reassigning `name` only changes the name shown
+    to the model; the original server-side name is preserved and used for the
+    actual tool invocation.
+
     Args:
         name (str): Tool name as registered on the server.
         description (str): Human-readable description from the server.
@@ -75,6 +81,7 @@ def __init__(
     ) -> None:
         """Store the spec fields and the transport config."""
         self.name = name
+        self._server_tool_name = name
         self.description = description
         self.input_schema = input_schema
         self._connection = connection
@@ -93,7 +100,7 @@ def as_mellea_tool(self) -> MelleaTool:
         """
         return MelleaTool(
             self.name,
-            _make_sync_call(self._connection, self.name),
+            _make_sync_call(self._connection, self._server_tool_name),
             {
                 "type": "function",
                 "function": {

test/stdlib/tools/test_mcp.py

@@ -75,6 +75,31 @@ async def test_produces_mellea_tool_with_correct_name(self, connection):
         assert isinstance(tool, MelleaTool)
         assert tool.name == "get_me"
 
+    @pytest.mark.asyncio
+    async def test_reassigned_name_calls_original_server_name(self, connection):
+        """Renaming a spec to disambiguate still invokes the server-side name."""
+        called_with: list[str] = []
+
+        async def _capture(tool_name, *, arguments):
+            called_with.append(tool_name)
+            return _call_result()
+
+        session = _make_session(_make_mcp_tool("get_me"))
+        session.call_tool = _capture
+
+        with _mock_open_session(session):
+            specs = await discover_mcp_tools(connection)
+
+        # A user reassigns name to avoid a collision with another server's tool.
+        specs[0].name = "github_get_me"
+
+        with _mock_open_session(session):
+            tool = specs[0].as_mellea_tool()
+            assert tool.name == "github_get_me"
+            tool.run()
+
+        assert called_with == ["get_me"]
+
     @pytest.mark.asyncio
     async def test_json_schema_structure(self, connection):
         schema = {"type": "object", "properties": {"q": {"type": "string"}}}