BerriAI/litellm · error · ValueError

name is required for tool {name}

Error message

name is required for tool {name}

What it means

Registry loader validation for tools declared in config: a tool entry reached registration without a name. This generic ValueError is raised while parsing the config list, before any handler resolution.

Source

Thrown at litellm/proxy/_experimental/mcp_server/tool_registry.py:130

            input_schema = tool_config.get("input_schema", {})
            handler_name = tool_config.get("handler")

            if not all([name, description, handler_name]):
                continue

            # Try to resolve the handler
            # First check if it's a module path (e.g., "module.submodule.function")
            if handler_name is None:
                raise ValueError(f"handler is required for tool {name}")
            handler = get_instance_fn(handler_name, config_file_path)

            if handler is None:
                verbose_logger.warning("Warning: Could not find handler %s for tool %s", handler_name, name)
                continue

            # Register the tool
            if name is None:
                raise ValueError(f"name is required for tool {name}")
            if description is None:
                raise ValueError(f"description is required for tool {name}")

            self.register_tool(
                name=name,
                description=description,
                input_schema=input_schema,
                handler=handler,
            )
        verbose_logger.debug("all registered tools: %s", json.dumps(self.tools, indent=4, default=str))


global_mcp_tool_registry: Final = MCPToolRegistry()

View on GitHub (pinned to 77b7c6c40c)

Solutions

1. Add a 'name' field to the tool entry in mcp_tools config.

Example fix

mcp_tools: [{name: 'my_tool', ...}]

When it happens

Trigger: Thrown at litellm/proxy/_experimental/mcp_server/tool_registry.py:130 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of BerriAI/litellm@77b7c6c40c (2026-08-18). Data as JSON: /api/errors/b351cdf4696b2772. Report an issue: GitHub.