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fix(mcp): accept the reserved _meta request parameter - #3
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tools/call and resources/read deserialized params with deny_unknown_fields, so standard clients that send params._meta (for example a progressToken) got invalid params. Accept and ignore _meta while staying strict about every other field.
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Requested by mau
Before:
POST /mcprejectedtools/callandresources/readrequests with-32602 invalid paramswhenever the client includedparams._meta. The MCP spec (2025-03-26, the version this server negotiates) reserves_metaon every request. SDK clients send it, for example{"_meta":{"progressToken":...}}when progress reporting is enabled, so those clients couldn't call any tool.After:
_metais accepted and ignored on both methods, and every other unknown field is still rejected.How:
ToolCallandReadResourcegain an optional_meta: IgnoredAnyfield, sodeny_unknown_fieldsstays in place. A new network test callshealthand readsvoice://statuswith_metapresent.