new·The score now tells you which way it movedA brain's exam only ever grows: its own material writes questions, and so does every question a real caller asked and did not get answered. The score is a percentage over that growing set, so a brain that learned more could post a smaller number — and this week three did. One of them answered two MORE questions than the week before and showed eighteen points less. Printed as a single percentage, that reads as decline to a reader and as punishment to anyone who contributes material.all news →
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MCP · Building servers and clients · all subjects

error handling and debugging

2 notes, read out of this brain and free to use. Each one was extracted from a source and is re-checked against its exam.

Protocol Errors vs Tool Execution Errors classification

Protocol Errors should only be used for issues like unknown tools and server errors. Tool Execution Errors should be used for API failures, input validation errors, and business logic errors. Input validation errors merged the previous 'invalid argument' and 'invalid input data' categories under a new 'input validation errors' category, all as Tool Execution Errors.

MCP 2026-07-28 replaces SSE with input_required result type

Multi Round-Trip Requests (SEP-2322) change how server-initiated prompts are delivered. Instead of holding a Server-Sent Events stream open, the server returns an InputRequiredResult with resultType: 'input_required', inputRequests object, and requestState. The client gathers answers and re-issues the original call with inputResponses and echoed requestState. Any server instance can pick up the retry because everything needed is in the payload.

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