agentscope-ai/agentscope · error · ValueError

Disable tools should be a list of strings, but got {self.dis

Error message

Disable tools should be a list of strings, but got {self.disable_tools}.

What it means

Same validation as enable_tools but for disable_tools: it must be None or a list of strings. Any other shape (bare string, set, list with non-string elements) raises this ValueError in model_post_init.

Source

Thrown at src/agentscope/mcp/_mcp_client.py:149

            raise ValueError(
                "STDIO MCP must be stateful (is_stateful=True).",
            )

        # Check arguments for self.enable_tools and disable_tools
        if self.enable_tools is not None:
            if not isinstance(self.enable_tools, list) or any(
                not isinstance(_, str) for _ in self.enable_tools
            ):
                raise ValueError(
                    "Enable tools should be a list of strings, but got "
                    f"{self.enable_tools}.",
                )

        if self.disable_tools is not None:
            if not isinstance(self.disable_tools, list) or any(
                not isinstance(_, str) for _ in self.disable_tools
            ):
                raise ValueError(
                    "Disable tools should be a list of strings, but got "
                    f"{self.disable_tools}.",
                )

        if self.enable_tools is not None and self.disable_tools is not None:
            intersection = set(self.enable_tools).intersection(
                set(self.disable_tools),
            )
            if len(intersection) != 0:
                raise ValueError(
                    f"The tools in enable_tools and disable_tools "
                    f"should not overlap, but got {intersection}.",
                )

        # Initialize the underlying client
        self._initialize_client()

    def _initialize_client(self) -> None:

View on GitHub (pinned to e90f1c7592)

Solutions

Use a list of strings: disable_tools=["dangerous_tool"]
Normalize config values (list(map(str, ...))) before constructing the client

Example fix

// before
client = MCPClient(name="fs", mcp_config=cfg, disable_tools="delete_file")

// after
client = MCPClient(name="fs", mcp_config=cfg, disable_tools=["delete_file"])

Defensive patterns

Strategy: validation

Validate before calling

disable_tools = None if disable_tools is None else [str(t) for t in disable_tools]
client = MCPClient(name=n, mcp_config=cfg, disable_tools=disable_tools)

Type guard

def is_tool_name_list(v) -> bool:
    return v is None or (isinstance(v, list) and all(isinstance(x, str) for x in v))

Try / catch

try:
    MCPClient(name=n, mcp_config=cfg, disable_tools=disable_tools)
except ValueError:
    disable_tools = list(map(str, disable_tools or [])) or None

Prevention

Mirror the enable_tools rules for disable_tools
Validate both filters with one shared helper
Prefer tuples->list conversion when configs come from YAML

When it happens

Trigger: MCPClient(..., disable_tools="dangerous_tool") or disable_tools=["a", None] or disable_tools=("a",).

Common situations: Symmetric with enable_tools mistakes: scalar tool name passed directly, or filters loaded from user-supplied config without normalization.

Related errors

AI-assisted analysis of agentscope-ai/agentscope@e90f1c7592 (2026-08-28). Data as JSON: /api/errors/ffa903b7dba284da. Report an issue: GitHub.