Tagged: troubleshooting
2026-10-27MCP error -32001: Request timed out, -32000: Connection closed, and other errors your client makes up"MCP error -32001: Request timed out" and "MCP error -32000: Connection closed" come from your MCP client's SDK, not from the server. What each one means, how to raise the 60-second timeout, and what changes in v2 of the TypeScript SDK.2026-10-27MCP error codes explained: protocol errors vs tool errorsWhich JSON-RPC and MCP error codes a server should send, when a failed tool call belongs in an isError result instead, and what reaches the model in each case.2026-10-25An unknown tool should get a JSON-RPC error, not isErrorA maintainer fixed the one observed risk on their MCP Checkup report. What the error_taxonomy check sends and expects, how to test your server with curl, and how often 3,309 servers answered an unknown tool with isError.2026-10-16MCP server returns 406 Not Acceptable: what it means and how to fix itFix "Not Acceptable: Client must accept both application/json and text/event-stream" (HTTP 406) from an MCP server: the exact SDK messages, how to reproduce them with curl, and the fix in the client, the server and the proxy.2026-10-12MCP server won't connect? Work through the error you getYour MCP server won't connect? Work through the error you get, from 401, 404 and redirects to timeouts and "MCP error -32000: Connection closed", with the curl command for each step.2026-10-10How to test an MCP server before you ship itA layer-by-layer way to test a remote MCP server from the outside — transport, handshake, tools/list, errors, auth and tool descriptions — with curl commands you can copy.2026-09-01Why does my MCP server show "observed-unsigned"?Five real protocol-level causes behind an "observed-unsigned" MCP Checkup report — four in a server's own setup, one a bug in our probe that we found and fixed. Each with a curl self-test and a fix.