Admin API

Problem types

Every error the Tandem Admin API returns is an RFC 9457 problem detail, served as application/problem+json. The type is always a canonical URL under https://tandem.codingful.com/problems/ — never about:blank.

The kebab-case slug is the stable machine identifier: match on it, not on title or detail, which are human-readable and may be reworded. A published slug never changes its meaning; a new problem type gets a new slug.

Type	Status	Meaning
`invalid-parameter`	400	A query or path parameter, or the request body, could not be parsed.
`replay-no-selector`	400	Bulk replay was called with no selector — it will not replay everything by default.
`ordering-break-not-acknowledged`	400	Discard requires acknowledging that skipping an event breaks ordering.
`unauthorized`	401	Missing or invalid credentials — produced by the host application, not by Tandem.
`not-found`	404	No such outbox message or relay bucket, or no operation at this path.
`method-not-allowed`	405	The path does not accept this HTTP method; `Allow` lists the ones it does.
`not-acceptable`	406	The `Accept` header admits nothing the operation returns.
`message-not-replayable`	409	The message is still in flight; only `DONE` or `FAILED` can be replayed.
`message-not-discardable`	409	Only a `FAILED` message can be discarded.
`relay-coordination-unsupported`	409	The operation needs per-bucket state that only `LEASE` coordination keeps.
`internal-error`	500	An unexpected failure; the detail is deliberately generic.