> ## Documentation Index
> Fetch the complete documentation index at: https://docs.orbit.devotel.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Errors worth branching on

> Per-endpoint failure templates matching the { error, meta } envelope — what actually fires, what to retry, what to surface to the operator.

## Errors worth branching on

These five failures cover the assistant turn (POST /api/v1/orby/sessions/{id}/messages), the heartbeat of every copilot chat. Each block below is a full `{ error, meta }` envelope as the API returns it, and the matrix at the bottom answers retry vs surface for the same five classes. For the platform-wide decision table these branches plug into, see the [error handling guide](/guides/error-handling-examples).

### 401 — Unauthorized

```json theme={null}
  {
    "error": {
      "code": "UNAUTHORIZED",
      "message": "The API key is invalid, expired, or lacks the required scope.",
      "status": 401
    },
    "meta": {
      "request_id": "req_orbya1",
      "timestamp": "2026-09-03T12:00:00Z"
    }
  }
```

A `401` on this page is the bearer key failing before the route ran — it never means the resource is wrong. Rotate the key or re-mint the scoped token; retrying the same request changes nothing.

### 403 — Forbidden

```json theme={null}
  {
    "error": {
      "code": "FORBIDDEN",
      "message": "The key is valid but does not have the scope this operation requires.",
      "status": 403
    },
    "meta": {
      "request_id": "req_orbya1f",
      "timestamp": "2026-09-03T12:00:00Z"
    }
  }
```

A `403` means the key authenticated but the operation is gated by scope — check the key's scopes on the developer page; a `403` is never a data-not-found shape.

### 422 — Schema

```json theme={null}
  {
    "error": {
      "code": "VALIDATION_ERROR",
      "message": "The request failed input validation.",
      "status": 422,
      "details": { "field": "session_id", "value": "sess_0192", "expected": "an active session id from POST /api/v1/orby/sessions" }
    },
    "meta": {
      "request_id": "req_orbyb2",
      "timestamp": "2026-09-03T12:00:00Z"
    }
  }
```

A `422` means the payload did not match the request schema — branch on `error.details.field` and open a new session and re-fire the same prompt against the fresh session id instead of blind-retrying the same body.

### 429 — Rate

```json theme={null}
  {
    "error": {
      "code": "RATE_LIMITED",
      "message": "Too many requests in the current window.",
      "status": 429,
      "details": { "retry_after": 12 }
    },
    "meta": {
      "request_id": "req_orbyc3",
      "timestamp": "2026-09-03T12:00:00Z",
      "docs_url": "https://docs.orbit.devotel.io/errors/RATE_LIMITED"
    }
  }
```

The `Retry-After` header and `error.details.retry_after` are both set on every `429` — resend the SAME request after the lower of the two.

### 402 — Feature gate

```json theme={null}
  {
    "error": {
      "code": "ORBY_BUDGET_EXCEEDED",
      "message": "The Orby run exceeded its token budget for this session.",
      "status": 402,
      "details": { "budget_tokens": 50000, "used_tokens": 51214 }
    },
    "meta": {
      "request_id": "req_orbyd4",
      "timestamp": "2026-09-03T12:00:00Z"
    }
  }
```

Rotate the session or return control to the operator; do not re-fire immediately.

### 60-second retry matrix

| Class                                         | Meaning                               | Branch response                                                                                               |
| --------------------------------------------- | ------------------------------------- | ------------------------------------------------------------------------------------------------------------- |
| **401 `UNAUTHORIZED`**                        | the bearer key itself fails           | **Surface.** Rotate the key or re-mint the scoped token; do not retry the same request.                       |
| **403 `FORBIDDEN`**                           | the key lacks this operation's scope  | **Surface.** Fix the key's scope set; a retry with the same key never heals it.                               |
| **422 `VALIDATION_ERROR`**                    | the payload does not match the schema | **Fix, then resend intentionally.** Branch on `error.details.field`; a blind retry repeats the same 422.      |
| **429 `RATE_LIMITED`**                        | the window quota is exhausted         | **Retry after `error.details.retry_after`** (or the `Retry-After` header) with the same request body.         |
| **`ORBY_BUDGET_EXCEEDED`** (402 feature gate) | page-specific gating                  | **Branch on `error.code`.** Rotate the session or return control to the operator; do not re-fire immediately. |