oauth_token_replay
HTTP 409
The same OAuth token (its jti) was already used to finalize. The jti is a one-time lock on the finalize step, so the replay seals nothing - mint a fresh token and check whether the first finalize succeeded before retrying.
Response shape
{
"type": "https://cogdepot.com/problems/oauth_token_replay",
"title": "<short human-readable summary>",
"status": 409,
"detail": "<what happened on this occurrence>",
"reason": "oauth_token_replay"
}Branch on reason. The title is prose and may be reworded; reason is the stable contract.