Inspired by Claude Code v2.1.219: MCP config string values with hidden
leading/trailing whitespace (pasted tokens with trailing newlines, URLs
with leading spaces) now trigger a startup warning naming the server and
the dotted key path, instead of failing later as an opaque auth/connect
error.
Advisory only: values are never mutated, secrets are never logged (only
key paths), and warnings dedupe to once per process per (server, path).
Checked after ${VAR} interpolation so whitespace inside referenced env
vars is caught too.
Teknium