Round 20, and almost all of it is fallout from round 19's two changes. Both
were right in direction and wrong in the detail, in the same way: each solved
its case by treating a broad thing as a proxy for a narrow one.
**The durability guard wrote newly entered secrets to disk in plaintext.**
Preserving legacy plaintext for a session-scoped store is correct — stripping
it moves the only durable copy into RAM. Using *the whole submitted entry* as
the proxy for "legacy" was not: it turned
`MCP_INSPECTOR_SECRET_STORE=memory` into "write every new secret to
`mcp.json` in the clear", while the footer for that very store says secrets
are written nowhere. A security regression introduced by a data-loss fix, and
the same overshoot in `client.json`.
Provenance decides now. A secret field is kept on disk only when it was
already there, unchanged, in the file being overwritten; a newly entered or
changed value is stripped and lives in the session store, which is exactly
what the footer promises. Where provenance cannot be established — an
unparseable prior file — the value is treated as new, because writing a
secret to disk on a guess is the failure that matters.
**The atomic claim was not as safe as its comments said.** Four ways:
- A crash between the claim and the copy left only
`secrets.json.migrating-<pid>`. The next run checked the canonical path,
found nothing, selected the keychain, and every stored credential vanished
with no warning. Orphans are now adopted at startup.
- Restoring used `rename`, which on POSIX **replaces** its destination — so
the restore path could overwrite a `secrets.json` a concurrent writer had
recreated, destroying the later successful write that claiming exists to
protect. The comment beside it asserted the opposite. `link` + `unlink` is
the no-clobber primitive this needed.
- Every claim failure was read as a lost race. `EACCES`/`EROFS` leave the
file exactly where it is, and returning quietly selected the keychain while
file-backed secrets sat there invisible. Only `ENOENT` is benign now.
- A failed cleanup left a plaintext-capable snapshot on disk with a silent
catch, while the app reported the keychain as the only store. It names the
path now.
**A third secret-entry surface had no disclosure at all.** `ServerConfigModal`
takes stdio `env` values, which are extracted into the store exactly as
Server Settings' are — and the footer's own doc comment claimed there were
only two such dialogs. It has the footer now, and every server write that can
carry a secret (config submit, both import flows) refreshes the descriptor,
not just the settings save.
Full `npm run ci` green, staged tree verified first.
Signed-off-by: cliffhall <cliff@futurescale.com>
15e9260484