{"version":"2.1.221","anchor":"failure-telemetry-errorcode-is-now-normalized-against-a-fixe","canonical_anchor":"failure-telemetry-errorcode-is-now-normalized-against-a-fixe","heading":"Failure telemetry errorCode is now normalized against a fixed allowlist","tier":"internal","area":"MCP","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.221\/e\/failure-telemetry-errorcode-is-now-normalized-against-a-fixe","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.221","markdown":"### Failure telemetry errorCode is now normalized against a fixed allowlist\n\nMCP connection failure reporting now uses a fixed set of error codes instead of raw values.\n\n**What**\n\n`errorCode` on `tengu_mcp_server_connection_failed` is no longer the raw stringified code.\n\n**Details**\n\n- It emits `missing` when absent, keeps numeric codes, keeps values from a fixed list, and otherwise reports `other`.\n- The list includes new entries such as `ERA_NEGOTIATION_FAILED`, `LIST_PAGINATION_EXCEEDED`, `METHOD_NOT_SUPPORTED_BY_PROTOCOL_VERSION` and the `CLIENT_HTTP_*` family.\n- The client-side error code map also gained `list_pagination_exceeded` plus explicit `-32000` and `-32001` entries.\n\n**Evidence**\n\n`METHOD_NOT_SUPPORTED_BY_PROTOCOL_VERSION`\n\n- Area: MCP\n- Tier: Under the hood\n- Useful: 1\/5\n- Signal: 0\/5"}