The Admin UI's Authorize & Fetch Token flow stored its pending server in a
module-level dict, so /register, /authorize and /token only succeeded when
every leg happened to land on the process that served /session. On a proxy
with NUM_WORKERS greater than 1, or more than one replica, each click was an
independent draw and failed with a bare 404, which reads as intermittent.
Persist the pending server as a short-lived draft row instead, so any worker
resolves it. The in-memory cache is kept as the fallback for proxies with no
database configured, which keeps single-process deployments working as before.
A session runs under a caller-supplied id only when that id names a server
that really exists, which is the edit form re-authorizing a saved server.
Anything else gets a fresh id, so two concurrent sessions can never share one
draft and silently adopt each other's URL or client credentials. Drafts past
their lifetime are swept on each write so abandoned sessions do not
accumulate, and a lost create race adopts the winner rather than failing a
caller whose session is ready.
Drafts are excluded from listings and never enter the runtime registry. The
exclusion keeps rows whose approval status is NULL, which both short spellings
of the filter drop, silently hiding every server predating the approval
workflow.
Measured on a two-worker proxy against the live GitHub MCP server, 120
concurrent authorize calls per leg: staging 56/120 failures, this branch
0/120, staging again 65/120 as a positive control.