openclaw - 💡(How to fix) Fix Mail MCP tools declare output schemas but return unstructured content, breaking list/read/move/mark [1 participants]

[tools] mail__list failed: MCP error -32600: Tool list has an output schema but did not return structured content [tools] mail__get_message_json failed: MCP error -32600: Tool get_message_json has an output schema but did not return structured content [tools] mail__read_message_contents failed: MCP error -32600: Tool read_message_contents has an output schema but did not return structured content [tools] mail__mark failed: MCP error -32600: Tool mark has an output schema but did not return structured content [tools] mail__move failed: MCP error -32600: Tool move has an output schema but did not return structured content

• mark/move operations fail with the same schema error
• scheduled mailbox-cleanup jobs are left in partial/error state [tools] mail__list failed: MCP error -32600: Tool list has an output schema but did not return structured content raw_params={"scope":"mailbox://inbox","limit":50,"presentation":"structured"} [tools] mail__list failed: MCP error -32600: Tool list has an output schema but did not return structured content raw_params={"scope":"mailbox://sent","presentation":"compact","limit":30} [tools] mail__get_message_json failed: MCP error -32600: Tool get_message_json has an output schema but did not return structured content raw_params={"identifier":"message://..."} [tools] mail__read_message_contents failed: MCP error -32600: Tool read_message_contents has an output schema but did not return structured content raw_params={"identifier":"message://...","maxChars":4000} [tools] mail__mark failed: MCP error -32600: Tool mark has an output schema but did not return structured content raw_params={"identifier":"message://...","status":"read"} [tools] mail__move failed: MCP error -32600: Tool move has an output schema but did not return structured content raw_params={"identifier":"message://...","toMailbox":"mailbox://Exchange/Archive"}

TL;DR

The most likely fix involves ensuring the Mail MCP server returns structured content matching its declared output schemas or modifying the OpenClaw MCP bridge to adapt plain/text responses into structured output.

Guidance

• Verify the Mail MCP server's response format to confirm whether it matches the declared output schemas.
• Check the OpenClaw MCP bridge configuration to ensure it is correctly set up to handle the Mail server's responses, potentially adapting plain/text to structured content.
• Review the tool descriptors for any mismatches between declared output schemas and actual result payloads.
• Consider temporarily modifying the Mail tools to not declare output schemas if the bridge cannot adapt the responses, as a workaround to restore basic functionality.

Example

No specific code snippet can be provided without more details on the bridge or server implementation, but ensuring the response from the Mail MCP server is JSON-formatted and matches the expected schema could resolve the issue.

Notes

The exact solution depends on the specifics of the Mail MCP server's implementation and the OpenClaw MCP bridge's capabilities, which are not fully detailed in the provided information.

Recommendation

Apply a workaround by either ensuring the Mail MCP server returns structured content or modifying the OpenClaw MCP bridge to correctly adapt responses, as upgrading to a fixed version is not mentioned as an option in the provided context. This approach is chosen because it directly addresses the suspected root causes of the issue.