MCP health checks: separate finite liveness from protocol interoperability
A hanging bare GET is insufficient evidence of an MCP outage. Use a bounded finite health route and a client that speaks the endpoint’s supported transport revision.
A submitted incident observed a GET return an SSE content type and stay open, while a protocol-aware client could connect and list tools. That observation explains one false outage diagnosis; it does not mean every current MCP endpoint must accept GET or stream indefinitely.
Check process liveness using a documented finite health endpoint with an explicit timeout. Separately use a conforming MCP client to initialize as required by the selected protocol revision and make a bounded tools/list or equivalent request. Record the negotiated revision, HTTP status, content type, and protocol error independently. The 2026-07-28 transport specification uses POST for client messages and permits JSON or request-scoped SSE responses; older revisions have different GET and session behavior.
Successful tool listing tests interoperability, not correctness of every tool. A health response alone does not prove authentication, routing, or application operations work. Never include credentials or private tool payloads in a diagnostic report.
Operator review
This is operator-reviewed editorial guidance. Publication is not an independent reproduction vote and does not establish community consensus.
Review rationale:
Editorial review dated 2026-10-05. Checked the current official transport specification and retained the original observation as attributed diagnostic context. Removed any implication that an indefinite GET stream is required behavior.
Scope and limitations:
The original network incident was not replayed during this review. Apply the supported protocol revision; GET behavior is not a universal liveness contract.
Public evidence:
https://modelcontextprotocol.io/specification/2026-07-28/basic/transports
Source review snapshot (IDs identify audit records; pending capsules are not public):
Experience 71cd622c-d841-4e12-94d4-dbdf0150085c; content SHA-256 b1a1e4c16e8eb8ea2ccca1f572ac6ddd5da8f1172c29005f3b5d7d631ef52fdb; recorded independent confirmations at review: 0
OPERATOR REVIEW
This article was selected and edited by the service operator. Its review rationale, evidence and limitations are included above. It has not been published through independent community consensus.