Fix MCP tool name conflicts by adding server name prefixes

src/agents/mcp/server.py

@@ -275,8 +275,14 @@ async def list_tools(
             # Reset the cache dirty to False
             self._cache_dirty = False
             # Fetch the tools from the server
-            self._tools_list = (await self.session.list_tools()).tools
-            tools = self._tools_list
+            tools = (await self.session.list_tools()).tools
+            # Add server name prefix to each tool's name to ensure global uniqueness
+            for tool in tools:
+                # Store original name for actual tool calls
+                tool.original_name = tool.name
+                # Prefix tool name with server name using underscore separator
+                tool.name = f"{self.name}_{tool.name}"
+            self._tools_list = tools
 
         # Filter tools based on tool_filter
         filtered_tools = tools
@@ -287,11 +293,23 @@ async def list_tools(
         return filtered_tools
 
     async def call_tool(self, tool_name: str, arguments: dict[str, Any] | None) -> CallToolResult:
-        """Invoke a tool on the server."""
+        """Invoke a tool on the server.
+
+        Args:
+            tool_name: The name of the tool to call. This can be either the prefixed name (server_name_tool_name)
+                    or the original tool name.
+            arguments: The arguments to pass to the tool.
+        """
         if not self.session:
             raise UserError("Server not initialized. Make sure you call `connect()` first.")
 
-        return await self.session.call_tool(tool_name, arguments)
+        # If the tool name is prefixed with server name, strip it
+        if "_" in tool_name and tool_name.startswith(f"{self.name}_"):
+            original_tool_name = tool_name.split("_", 1)[1]
+        else:
+            original_tool_name = tool_name
+
+        return await self.session.call_tool(original_tool_name, arguments)
 
     async def list_prompts(
         self,

src/agents/mcp/util.py

@@ -161,7 +161,6 @@ def to_function_tool(
             on_invoke_tool=invoke_func,
             strict_json_schema=is_strict,
         )
-
     @classmethod
     async def invoke_mcp_tool(
         cls, server: "MCPServer", tool: "MCPTool", context: RunContextWrapper[Any], input_json: str
@@ -178,21 +177,24 @@ async def invoke_mcp_tool(
                 f"Invalid JSON input for tool {tool.name}: {input_json}"
             ) from e
 
+        # Use original tool name for server call (strip server prefix if present)
+        original_name = getattr(tool, 'original_name', tool.name)
+
         if _debug.DONT_LOG_TOOL_DATA:
-            logger.debug(f"Invoking MCP tool {tool.name}")
+            logger.debug(f"Invoking MCP tool {tool.name} (original: {original_name})")
         else:
-            logger.debug(f"Invoking MCP tool {tool.name} with input {input_json}")
+            logger.debug(f"Invoking MCP tool {tool.name} (original: {original_name}) with input {input_json}")
 
         try:
-            result = await server.call_tool(tool.name, json_data)
+            result = await server.call_tool(original_name, json_data)
         except Exception as e:
             logger.error(f"Error invoking MCP tool {tool.name}: {e}")
             raise AgentsException(f"Error invoking MCP tool {tool.name}: {e}") from e
 
         if _debug.DONT_LOG_TOOL_DATA:
-            logger.debug(f"MCP tool {tool.name} completed.")
+            logger.debug(f"MCP tool {tool.name} (original: {original_name}) completed.")
         else:
-            logger.debug(f"MCP tool {tool.name} returned {result}")
+            logger.debug(f"MCP tool {tool.name} (original: {original_name}) returned {result}")
 
         # The MCP tool result is a list of content items, whereas OpenAI tool outputs are a single
         # string. We'll try to convert.