fix(time): use McpError for proper JSON-RPC error propagation#4483
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isheng-eqi wants to merge 2 commits into
Open
fix(time): use McpError for proper JSON-RPC error propagation#4483isheng-eqi wants to merge 2 commits into
isheng-eqi wants to merge 2 commits into
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Two fixes in the time server:
1. call_tool handler (line 216): Was raising plain ValueError instead of
McpError. The MCP protocol requires JSON-RPC errors via McpError with
proper error codes. A ValueError propagates as a generic internal error
to the client, losing the error context.
2. get_zoneinfo (line 56): Catch KeyError specifically for unknown
timezones vs. generic exceptions for invalid timezone strings. Gives
the client more precise error messages ('Unknown timezone' vs
'Invalid timezone').
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Summary
Two fixes in the time server for proper MCP protocol error handling.
Problem
call_toolhandler raisedValueErrorinstead ofMcpError(line 216). The MCP protocol requires errors to be sent as JSON-RPC error responses viaMcpError. A bareValueErrorgets caught by the SDK as a generic internal error, losing the error code and context.get_zoneinfocaught all exceptions generically (line 56).ZoneInfo("invalid")raisesKeyErrorwhileZoneInfo(bad_object)raisesTypeError— the function gave the same "Invalid timezone" message for both, making debugging harder.Changes
src/time/src/mcp_server_time/server.py(+4/-2):get_zoneinfo: separateKeyError(unknown timezone name) from generic exceptions (invalid format), with distinct messagescall_toolhandler:ValueError→McpError(ErrorData(code=INVALID_PARAMS, ...))for correct JSON-RPC error propagation