fix(mcp): surface real error in collection validation catch#383
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mvanhorn wants to merge 1 commit into
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fix(mcp): surface real error in collection validation catch#383mvanhorn wants to merge 1 commit into
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The catch block in handlers.ts interpolated `err.message || err`, which falls through to default object stringification when the thrown value is a plain object without a `.message` property. The user-facing MCP response ended up reading "Error validating collection creation: [object Object]". Replace the antipattern with a `formatValidationError` helper that tries `err.message`, then nested `response.data.message` and `response.data.detail`, then `response.statusText`, then JSON.stringify, and only falls back to String(err) when nothing usable can be extracted. Apply the helper to the same antipattern at the other catch sites in the file (sync, fallback query, snapshot delete, indexing dispatcher). `npx tsc --noEmit` on packages/mcp passes after this change. Fixes zilliztech#215
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Summary
Replace the
err.message || errinterpolation in the MCP catch blocks with a smallformatValidationErrorhelper so users see the actual error from Zilliz / Milvus instead of[object Object].Why this matters
Issue #215 reports
Error validating collection creation: [object Object]fromindex_codebase. Multiple users in the thread confirm the same opaque message (@DeadManPoe on Rust, @Wazabit on a NestJS TS codebase, @PeterSenyszyn, @mahmoudnaif, @KrustyHack). @PeterSenyszyn traced the root cause: Zilliz Cloud free tier caps collections at 5 per cluster, and the create call rejects past that.The catch at
packages/mcp/src/handlers.ts:463interpolated${validationError.message || validationError}. WhenvalidationErroris a plain object without.message, the||fallback returns the object itself and template coercion produces[object Object]. The same antipattern repeats at four other catch sites in the file (cloud sync description, fallback query, snapshot delete, indexing dispatcher).formatValidationErrortries, in order:err.message(when it's a non-empty string and not literally[object Object])err.response.data.messageerr.response.data.detailerr.response.statusTextJSON.stringify(err)(when the result is not{}ornull)String(err)(final fallback)This turns the Zilliz collection-limit error and similar response-bearing errors into a readable message at every existing catch site without changing the surrounding flow.
checkCollectionLimititself is not modified; this is purely a presentation fix.Testing
npx tsc --noEmitonpackages/mcppasses.Fixes #215