Three refusals still answered 401 with prose alone: the Bearer re-read on
`/api/auth/me/sessions`, and the wrong-second-factor arm on both MFA step-up
routes. The shared 401 description told clients the code is the field to
branch on, so a client that took that advice landed in its default arm on all
three — and on the MFA pair that is the difference between re-prompting for a
digit and signing the user out over a typo.
The sessions re-read is the same missing-credential fact the gate already
names, so it reuses `auth.missing`. The MFA pair gets a code of its own,
`auth.mfa.code_invalid`: none of the existing ones fit, because every other
401 code asks the client to discard something, and this one asks it to keep
the session and try another code.
The description narrows to match what is actually true. The generic gates
name a reason; a route that checks a credential of its own — sign-in, the MFA
challenge exchange, a password confirmation — still answers 401 with prose,
and the text now says so instead of promising a field those responses do not
carry.
`requireAuth`, `requireAdmin`, `requireCookieAuth`, `requireFreshMfa` and
`requireBearerAuth` all refused with a bare prose string and no `meta`.
So the single most important branch a native client makes — refresh the
token and retry, drop the session and show the login screen, or stop
retrying because this credential will never work — could only be made by
string-matching the English sentence "Token expired". Any rewording of
that string, or a localisation pass, silently turns a recoverable
refresh into a forced logout for every already-shipped build.
The mechanism was already here and these gates were the ones skipped:
the assistant, consent, step-up, module and sharing refusals all carry
`meta.errorCode`, and `/api/auth/refresh` emits `auth.refresh.*`. So
`HttpError` takes an optional code and the wrapper puts it in the same
field. Five values, dot.case like the majority: `auth.missing`,
`auth.token.expired`, `auth.token.invalid`, `auth.scope.insufficient`,
`auth.admin.required`. A revoked token reads invalid, not expired —
refreshing a revoked token loops forever.
Additive: an HttpError thrown without a code serialises byte-identically
to before, which is most of them. The published 401 description now
enumerates the codes and says what a client should do with each.
api-handler imports the record-session fence and the fence threw
RecordSessionChangedError / SharingAccessDeniedError imported back from
api-handler — the one real import cycle in the tree, working only by
evaluation-order luck. HttpError, the SharingAuthError family and
StepUpRequiredError now live in api-errors.ts (importing nothing but
the fence contract), api-handler re-exports the identical class objects
so no importer moves, and the fence imports the leaf. A guard pins both
the identity and the leaf structure.
Marc-André Bombeck