Errors - Momor Gateway docs

Statuses

Status	Cause	What to do
`401`	No authenticated caller.	Check the `Authorization` header. The `GET /models/...` catalogs need no token.
`404`	No configured model answers to that name, or none that does runs on a key you hold or one Momor resells.	Read the catalog. The name is wrong, that model is not configured here, it is a model of another type than the route serves, such as a decision model sent to `/models/chat`, or none of its rows says `resale: true` and you sent no key of your own for its providers. Under zero data retention, only saved keys marked `zdr` and Momor's keys its own agreements cover count.
`400`	Invalid JSON or a public-contract validation failure.	Fix the request. Numeric enums, stored handles and internal tool-routing kinds are rejected. A property Momor does not read is ignored, and a parameter value is never checked against a provider's range. Under zero data retention, `fileProcessing` other than `none` is refused.
`406`	`Accept` does not allow the response selected by `streaming`.	Allow `application/json` for unary calls or `text/event-stream` for streams. `Accept` never changes execution mode.
`413`	The request body or inline-file limits were exceeded.	Send large files by URL rather than inline bytes. Public file handles are rejected.
`415`	The request is not `application/json`.	Set `Content-Type: application/json`.
`422`	Models matched, and every one refused this request.	A capability you asked for is not offered — tools, a schema, streaming or a file type. Retrying will not help.
`429`	The caller exceeded the gateway's request-rate limit.	Read `Retry-After` and `X-RateLimit-Reset` before retrying.
`503`	The candidate ladder was exhausted by provider/transport failures.	Retry after a delay or broaden the selector.
`504`	The provider did not answer within the call's network timeout, or within the gateway's own limit.	Retry, or broaden the selector to a faster model. A `networkTimeout` you set only ever shortens the wait.
The provider's own	Every candidate was tried and failed upstream.	The status and message are the provider's, passed through. Treat it as you would treat that provider directly.
`502`	A stream opened and produced nothing, or ended without a terminal event.	Safe to retry. Arrives as an error frame inside the stream, not as an HTTP status.
`502`	A provider refused the key you sent or saved for it.	Check the key with the provider. The message names the provider.

Error bodies

Unary failures are RFC 7807 problem documents. Streamed failures are frames on the stream, because the HTTP status was already sent when the stream opened.

HTTP/1.1 404 Not Found
Content-Type: application/problem+json
{
  "status": 404,
  "detail": "No configured model answers to claud-sonnet-5."
}

event: error
data: {"success":false,"code":502,"message":"Stream ended without a terminal event."}

The messages you will see

`detail`	Meaning
`No configured model answers to <name>.`	Nothing in the catalog matches the name, tier and provider you asked for, in the system the route names. A model not yet classified is never served, and a tier, `auto` or `*` also leaves out deprecated models and those released on or before the cut-off.
`No configured model answering to <name> runs on a key the caller or Momor holds.`	`404`. Models matched, and none of them runs on your own key or on a key Momor resells. Send your key for one of its providers in `keys`, or choose a model whose catalog row says `resale: true`. Under zero data retention, that is a saved key marked `zdr` or a Momor key its own agreements cover; a key sent with the call is not used.
`No configured model supports this request.`	Models matched the selector, but none could carry every capability the request requires. Read the catalog to compare tools, structured output, streaming and content types.
`<model> requires MaxTokens.`	The Anthropic API requires an output ceiling. Set `parameters.maxTokens`.
`<model> requires max_tokens.`	The same ceiling on a Chat Completions call. Set `max_tokens` or `max_completion_tokens`.
`<model> has no block for <type> content here.` · `<model> has no part for <type> content.`	Anthropic or Gemini has no way to carry that part of a Chat Completions call. The call moved on to the next candidate; this is the answer only where no candidate could carry it.
`prioritization names <provider>, which this deployment does not serve.`	Read the catalog's `provider` values. A region is named `name@region`, such as `azure@eu`, and must be one the deployment serves.
`prioritization both orders and ignores <provider>.`	Name a provider in `order` or `ignore`, not both.
`'provider.zdr' must be a boolean.`	`400`. On Chat Completions, `provider.zdr` is `true` or `false`.
`keys names <provider>, which this deployment does not serve.`	Send keys only for providers the catalog lists.
`<provider>@<region> serves no model that runs on a caller's own key.`	`400`. A key cannot be saved for that region alone. Save it for the root, which runs the root and all its regions.
`<provider> has no model a key for it is tried against.`	That provider's key cannot be saved or tested. It still works per call, sent in `keys`.
`<provider> refused the caller's own key for it: …`	`502`. The provider turned your key away; check it with the provider.
`<provider> is rate-limiting the caller's own key: …`	`429`. The limit is your key's own; wait it out or send no key.
`A decision carries its questions as systemPrompt, an array of at least one question.`	`POST /models/decision` takes `systemPrompt` as an array of questions, and at least one.
`A decision takes no stream, tools or responseSchema.`	Leave `streaming`, `tools` and `responseSchema` out of a decision.
`Every question needs a name of its own.`	Give each question a `name`, and no two the same.
`Question <name> needs instructions.`	Say what the question asks in `instructions`.
`Question <name>'s criteria do not fit a <type>: …`	A `boolean` explains `true` and `false`, a `choice` explains at least two values, and a `score` lists two to ten levels, lowest first.
`<model> decides on text alone, not <type>.`	The provider's `400`, ending `by address` where the file came as a URL. That decision model reads a text or JSON file as it is, and any other file only as the text it was parsed to.
`<model> decides on text and inline images alone, not <type>.`	The provider's `400`, ending `by address` where the file came as a URL. Send an image, text or JSON file inline, or have any other file parsed to text.
`<model> decides on user messages alone.`	The provider's `400`. A decision reads the user's messages only; leave the model's turns and tool results out.
`A transcription carries one recording, an audio file attached to a user message.`	`POST /models/transcribe` and `POST /v1/audio/transcriptions` take exactly one `audio/*` file.
`A transcription takes no stream, tools or responseSchema.`	Leave `streaming`, `tools` and `responseSchema` out of a transcription.
`<model> transcribes a recording sent with the call, not one by address.`	The recording came as a URL. Send it inline, or as a file Momor holds.
`'response_format' is json or text.`	`POST /v1/audio/transcriptions` answers `json` or `text`.
`<model> takes at most <count> options a question.` · `<model> takes at most <count> choices a question.`	The provider's `400`. That decision model takes no more options in one question: 24 on Tev1, 255 choices on Jev.
`<model> answered <question> with '<letter>', which is not one of its option letters.`	`502`. The model answered outside the options it was given; safe to retry.

Capability refusals remain internal. Several candidates can refuse for different reasons, so the aggregate does not select one candidate's explanation and present it as the answer for the whole ladder.

status is the machine-readable contract. detail is present on router-originated failures; framework rejections such as an unsupported content type can instead carry a title. Problem type and tracing headers are not yet a stable Gateway contract.

Upstream failures

A provider's own status and message reach you unchanged, so you get its rate-limit, overload and content-policy signals rather than a translation of them. Handle them as you would handle that provider directly.

Known rough edge For OpenAI-compatible providers whose error body is not OpenAI's error object, the message is the client library's rendering of the failure rather than the provider's bare text, so it can read like Service request failed. followed by the status. The status is correct; the prose is noisier than it should be.

What is worth retrying

Outcome	Retry?
`400` · `401` · `404` · `406` · `413` · `415` · `422`	No. The request is wrong, or the deployment cannot serve it.
`502`	Yes, unless a provider refused your own key.
`503`	Yes, after a delay.
`504`	Yes, or with a wider selection.
Provider `429` / `5xx`	Only after a delay, or with a wider selection.

Before returning any upstream failure, Momor has already stepped through every other model that could have served the request. You are not being asked to do the failover — you are being told it was exhausted.