Publish review_upload as one object so Anthropic accepts it - #621
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OpenCode forwards MCP input schemas to the Anthropic API unchanged, and the API rejects oneOf/anyOf/allOf at the top level of a tool input_schema. The upload tool published its discriminated union verbatim, so enabling Whiteboard broke every request. Claude Code flattens such schemas itself, which hid the problem there. Publish upload as one object with kind as an enum and the kind-specific fields optional; the host still validates the union. Agent-Session: 0e2e21cf-19cf-4e82-b801-11a38760f54a Agent-Session: ffd15b4f-a561-403e-bf42-e841bd247f58
Agent-Session: 0e2e21cf-19cf-4e82-b801-11a38760f54a Agent-Session: ffd15b4f-a561-403e-bf42-e841bd247f58
sidkmenon
approved these changes
Sep 27, 2026
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Fixes a user report: with OpenCode, requests fail with
tools.302.custom.input_schema: input_schema does not support oneOf, allOf, or anyOf at the top level.The upload tool published
uploadSchema, az.discriminatedUnion, as its input schema, so the JSON Schema had a top-leveloneOf. The Anthropic API rejects that. OpenCode forwards MCP schemas unchanged, so enabling Whiteboard broke every request. Claude Code flattens top-level combinators itself, which is why it kept working there.review_upload/session_uploadnow publish one object:id,repositoryIdandkind(enumimage | trace | map) are required, and the kind-specific fields (base64,trace,pins,side,model) are optional. The flat shape is derived fromuploadSchema.options, so the two can't drift apart.anyOf,oneOforallOf. It failed onsession_uploadbefore this change.Pi is unaffected: its package is a skill that shells out to
whiteboard api, so no MCP schema goes to the model.Verification
vitest run src/review-api: 315 passed.pnpm lintand thepackages/reviewtypecheck are clean.session_uploadwith a flat image payload.anthropic/claude-haiku-4-5against the same stub server: the old tool list reproduces the reportedtools.N.custom.input_schemaerror, and the new one produces a correctsession_uploadcall.gpt-6-solagainst the same stub server: the old and new tool lists produce the samesession_uploadcall. OpenAI accepts the top-leveloneOf, so Codex was never affected.The MCP adapter reads tool schemas from the running host, so users get this fix when their Whiteboard Desktop updates.