agentscope-ai/agentscope · error · ValueError

The tools in enable_tools and disable_tools should not overl

Error message

The tools in enable_tools and disable_tools should not overlap, but got {intersection}.

What it means

MCPClient rejects configurations where a tool name appears in both enable_tools and disable_tools, since the filter behavior would be ambiguous. The error message includes the overlapping tool names.

Source

Thrown at src/agentscope/mcp/_mcp_client.py:159

                    "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:
        """Pre-build the stdio client context manager."""
        if self.mcp_config.type == "stdio_mcp":
            config = self.mcp_config
            self._client = stdio_client(
                StdioServerParameters(
                    command=config.command,
                    args=config.args or [],
                    env=config.env,
                    cwd=str(config.cwd) if config.cwd else None,
                    encoding="utf-8",

View on GitHub (pinned to e90f1c7592)

Solutions

Remove the overlapping tool(s) listed in the error from either enable_tools or disable_tools
If both lists come from separate configs, deduplicate/intersect-check before constructing MCPClient

Example fix

// before
client = MCPClient(name="m", mcp_config=cfg,
    enable_tools=["search", "fetch"],
    disable_tools=["fetch"],
)

// after
client = MCPClient(name="m", mcp_config=cfg,
    enable_tools=["search", "fetch"],
    disable_tools=["delete"],
)

Defensive patterns

Strategy: validation

Validate before calling

if enable_tools and disable_tools:
    overlap = set(enable_tools) & set(disable_tools)
    assert not overlap, f"tools in both filters: {overlap}"
client = MCPClient(name=n, mcp_config=cfg, enable_tools=enable_tools, disable_tools=disable_tools)

Try / catch

try:
    MCPClient(name=n, mcp_config=cfg, enable_tools=en, disable_tools=dis)
except ValueError as e:
    if "should not overlap" in str(e):
        dis = [t for t in dis if t not in set(en)]

Prevention

Treat enable_tools as the authoritative allowlist and derive disable_tools by difference
Validate config composition when merging MCP filter settings from multiple sources
Unit-test filter configs for disjointness

When it happens

Trigger: MCPClient(..., enable_tools=["search", "fetch"], disable_tools=["fetch"]) — any non-empty intersection of the two lists.

Common situations: Appending to one filter list during development while forgetting the tool is already in the other; merging filter configs from multiple sources; copy-paste between enable and disable blocks.

Related errors

AI-assisted analysis of agentscope-ai/agentscope@e90f1c7592 (2026-08-28). Data as JSON: /api/errors/414a4958dfdaaf81. Report an issue: GitHub.