> ## Documentation Index
> Fetch the complete documentation index at: https://docs.beta.b3os.org/llms.txt
> Use this file to discover all available pages before exploring further.

# List library backgrounds

Lists the background library: backgrounds a style names with `overrides.background_ref`, each drawn by the compositor from CSS gradient layers (no image files), with its license and source. Every entry is redistributable (MIT or B3OS's own); the MIT packs name their notice in `GET /v1/render/backgrounds/packs`. Public: no API key, rate limited per client address, and answered from the edge's cache for up to 5 minutes. The whole library fits in one page, so `next_cursor` is always null. 

` GET /v1/render/backgrounds `

List library backgrounds

Lists the background library: backgrounds a style names with `overrides.background_ref`, each drawn by the
compositor from CSS gradient layers (no image files), with its license and source. Every entry is
redistributable (MIT or B3OS's own); the MIT packs name their notice in `GET /v1/render/backgrounds/packs`.
Public: no API key, rate limited per client address, and answered from the edge's cache for up to 5 minutes.
The whole library fits in one page, so `next_cursor` is always null.


## Servers

- ` https://beta-api.b3os.org ` — API (API keys and CLI tokens)

- ` https://beta.b3os.org ` — Dashboard (session cookie and CSRF header; same paths)

## Parameters

### ` pack ` (query, optional)

Only this pack's backgrounds.

- ` value `: type ` string `

  - pattern: ` "^[a-z0-9][a-z0-9_-]{0,63}$" `

Example:

```json
"patterncraft"
```

### ` theme ` (query, optional)

Only light or only dark backgrounds.

- ` value `: type ` string `

  - enum: ` ["light","dark"] `

### ` q ` (query, optional)

Only backgrounds whose name, slug or tags contain this text (case-insensitive).

- ` value `: type ` string `

  - maxLength: ` 64 `

## Responses

### ` 200 ` — The backgrounds, in `ref` order.

Content type: ` application/json `

- ` value `: type ` unknown `

  - ` allOf constraint 1 `: type ` object ` — A page of results. Pass `next_cursor` as `cursor` to get the next page; it is `null` on the last page. Pages are ordered newest first unless the operation says otherwise. 

    - Required fields: ` object `, ` data `, ` next_cursor `

    - ` object `: type ` string `

      - enum: ` ["list"] `

    - ` data `: type ` array `

      - ` array item `: type ` unknown `

    - ` next_cursor `: type ` string `; nullable

  - ` allOf constraint 2 `: type ` object `

    - ` data `: type ` array `

      - ` array item `: type ` object ` — A library background. Name it in a style with `overrides.background_ref` (as `style` shows).

        - Required fields: ` ref `, ` object `, ` kind `, ` pack `, ` slug `, ` name `, ` theme `, ` tags `, ` palette `, ` tokens `, ` license `, ` source `, ` thumbnail_url `, ` style `

        - ` ref `: type ` string ` — `<pack>/<slug>`, the value of `overrides.background_ref`.

          - pattern: ` "^[a-z0-9][a-z0-9_-]{0,63}/[a-z0-9][a-z0-9_-]{0,127}$" `

        - ` object `: type ` string `

          - enum: ` ["render.background"] `

        - ` kind `: type ` string ` — `css`: drawn by the compositor from gradient layers.

          - enum: ` ["css"] `

        - ` pack `: type ` string `

        - ` slug `: type ` string `

        - ` name `: type ` string `

        - ` description `: type ` string `

        - ` theme `: type ` string `

          - enum: ` ["light","dark"] `

        - ` tags `: type ` array `

          - ` array item `: type ` string `

        - ` palette `: type ` array ` — The main colors, as the source lists them.

          - ` array item `: type ` string `

        - ` tokens `: type ` object ` — Color tokens and their defaults; `overrides.background_tokens` sets new colors for them.

        - ` license `: type ` string ` — `MIT` or `own` (B3OS's own work).

        - ` source `: type ` object ` — Where the background comes from.

          - Required fields: ` url `

          - ` url `: type ` string `; format ` uri `

          - ` path `: type ` string `

          - ` commit `: type ` string `

          - ` id `: type ` string `

          - ` via `: type ` string `

        - ` thumbnail_url `: type ` string `; format ` uri ` — A 360x200 WebP drawn by the compositor, a B3OS static asset under `https://beta.b3os.org/assets/presets/library/`.

        - ` style `: type ` object ` — The `style` value that draws this background.

          - Required fields: ` overrides `

          - ` overrides `: type ` object `

            - Required fields: ` background_ref `

            - ` background_ref `: type ` string `

Response header ` x-request-id ` — The request ID (`req_…`). It is the `instance` of any problem and the key for `GET /v1/requests/{request_id}`.

- ` value `: type ` string `

  - pattern: ` "^req_[0-9a-hjkmnp-tv-z]{26}$" `

Response header ` Server-Timing ` — Phase durations in milliseconds (W3C Server Timing); the handler's phases break the request down. For a
response whose body size is known, `total` runs from reading the request head to writing the response head.
Streaming responses (event streams, WebSockets, chunked bodies) carry no `total` here: they report their
final phases in the terminal event (`job.succeeded`, `job.failed`, `job.canceled`) or the final job. The
time from the first request byte to the last response byte is recorded in the node's metrics and request
log (`GET /v1/requests/{request_id}`). The edge prepends `edge_auth` and `edge_upstream`.


- ` value `: type ` string `

Example:

```json
{
  "object": "list",
  "data": [
    {
      "ref": "patterncraft/top-amber-glow",
      "object": "render.background",
      "kind": "css",
      "pack": "patterncraft",
      "slug": "top-amber-glow",
      "name": "Top Amber Glow",
      "description": "White with a warm amber radial glow from the top",
      "theme": "light",
      "tags": [
        "amber",
        "warm",
        "top",
        "glow",
        "light",
        "energetic"
      ],
      "palette": [
        "#ffffff",
        "#f59e0b"
      ],
      "tokens": {
        "accent": "#f59e0b"
      },
      "license": "MIT",
      "source": {
        "url": "https://github.com/megh-bari/pattern-craft",
        "path": "src/data/patterns.ts",
        "commit": "d36a8d515d507381447871fa41ea511e90defb44",
        "id": "top-amber-glow"
      },
      "thumbnail_url": "https://beta.b3os.org/assets/presets/library/patterncraft/top-amber-glow.webp",
      "style": {
        "overrides": {
          "background_ref": "patterncraft/top-amber-glow"
        }
      }
    }
  ],
  "next_cursor": null
}
```

### ` 400 ` — The request failed validation (`invalid_request`, `invalid_url`).

Content type: ` application/problem+json `

- ` value `: type ` object ` — An RFC 9457 problem. `code` is stable and listed in the errors catalog; `type` links to its entry. `detail` is human-readable and may change. Extension members appear only for the codes that document them; ignore members you do not recognize. 

  - Required fields: ` type `, ` title `, ` status `, ` code `, ` detail `

  - ` type `: type ` string `; format ` uri ` — `https://docs.beta.b3os.org/errors#<code>`.

    - example: ` "https://docs.beta.b3os.org/errors#invalid_request" `

  - ` title `: type ` string ` — Short summary of the problem type.

  - ` status `: type ` integer ` — The HTTP status code, repeated for convenience.

    - minimum: ` 400 `

    - maximum: ` 599 `

  - ` code `: type ` string ` — Stable machine-readable error code from the errors catalog.

    - pattern: ` "^[a-z][a-z0-9_]*$" `

  - ` detail `: type ` string ` — Explanation of this occurrence. Never contains secrets.

  - ` instance `: type ` string ` — The request ID (`req_…`) of the request that failed. Include it when you contact support.

    - example: ` "req_01m5t4yg394wegr3j4y01qb363" `

  - ` errors `: type ` array ` — Validation problems, one per field (`invalid_request` and the other codes that list `errors`).

    - ` array item `: type ` object ` — One validation problem.

      - Required fields: ` pointer `, ` detail `

      - ` pointer `: type ` string ` — Where the problem is: a JSON pointer into the request body (`/url`, `/steps/0/uses`), or `#query/<name>`, `#path/<name>` or `#header/<name>` for parameters. 

        - example: ` "/url" `

      - ` detail `: type ` string ` — What is wrong there.

        - example: ` "must be an absolute http or https URL" `

  - ` reason `: type ` string ` — Finer-grained cause for codes that document one (`unauthorized`, `forbidden`, `egress_denied`, `upstream_unreachable`, …).

  - ` required_scope `: type ` string ` — The scope that was missing (`forbidden` with `reason: scope`).

  - ` retry_after_s `: type ` integer ` — Same value as the `Retry-After` header, for clients that only read the body.

    - minimum: ` 0 `

  - ` limit `: type ` object ` — The limit an error refers to. IDs and current values are listed by `GET /v1/limits`.

    - Required fields: ` id `, ` limit `, ` unit `

    - ` id `: type ` string ` — Limit ID, such as `vision.scrape.rpm` or `sandboxes.concurrent`.

      - example: ` "vision.scrape.rpm" `

    - ` limit `: type ` number ` — The limit's value.

    - ` unit `: type ` string ` — What the limit counts, such as `requests`, `sandboxes`, `vcpu` or `MiB`.

    - ` window_s `: type ` integer ` — Window length in seconds for rate limits and quotas.

    - ` current `: type ` number ` — Current usage against the limit, when known.

  - ` current_status `: type ` string ` — The object's current status, for state conflicts such as `sandbox_not_running`.

  - ` upstream_status `: type ` integer ` — The HTTP status the upstream returned (`upstream_error`, `action_output_invalid`).

  - ` step `: type ` string ` — The failed step, as a step ID (routines), an index (`act`) or a path such as `beats/2/do/0` (render).

  - ` pack_error `: type ` object ` — The error a pack's error mapping chose (`upstream_error` from pack actions).

    - Required fields: ` code `, ` message `, ` retryable `

    - ` code `: type ` string `

    - ` message `: type ` string `

    - ` retryable `: type ` boolean `

Response header ` x-request-id ` — The request ID (`req_…`). It is the `instance` of any problem and the key for `GET /v1/requests/{request_id}`.

- ` value `: type ` string `

  - pattern: ` "^req_[0-9a-hjkmnp-tv-z]{26}$" `

Response header ` Server-Timing ` — Phase durations in milliseconds (W3C Server Timing); the handler's phases break the request down. For a
response whose body size is known, `total` runs from reading the request head to writing the response head.
Streaming responses (event streams, WebSockets, chunked bodies) carry no `total` here: they report their
final phases in the terminal event (`job.succeeded`, `job.failed`, `job.canceled`) or the final job. The
time from the first request byte to the last response byte is recorded in the node's metrics and request
log (`GET /v1/requests/{request_id}`). The edge prepends `edge_auth` and `edge_upstream`.


- ` value `: type ` string `

Example:

```json
{
  "type": "https://docs.beta.b3os.org/errors#invalid_request",
  "title": "Invalid request",
  "status": 400,
  "code": "invalid_request",
  "detail": "1 field failed validation",
  "instance": "req_01m5t4yg394wegr3j4y01qb363",
  "errors": [
    {
      "pointer": "/url",
      "detail": "must be an absolute http or https URL"
    }
  ]
}
```

### ` 429 ` — A rate, concurrency or quota limit applies (`rate_limited`, `concurrency_limited`, `quota_exceeded`).

Content type: ` application/problem+json `

- ` value `: type ` object ` — An RFC 9457 problem. `code` is stable and listed in the errors catalog; `type` links to its entry. `detail` is human-readable and may change. Extension members appear only for the codes that document them; ignore members you do not recognize. 

  - Required fields: ` type `, ` title `, ` status `, ` code `, ` detail `

  - ` type `: type ` string `; format ` uri ` — `https://docs.beta.b3os.org/errors#<code>`.

    - example: ` "https://docs.beta.b3os.org/errors#invalid_request" `

  - ` title `: type ` string ` — Short summary of the problem type.

  - ` status `: type ` integer ` — The HTTP status code, repeated for convenience.

    - minimum: ` 400 `

    - maximum: ` 599 `

  - ` code `: type ` string ` — Stable machine-readable error code from the errors catalog.

    - pattern: ` "^[a-z][a-z0-9_]*$" `

  - ` detail `: type ` string ` — Explanation of this occurrence. Never contains secrets.

  - ` instance `: type ` string ` — The request ID (`req_…`) of the request that failed. Include it when you contact support.

    - example: ` "req_01m5t4yg394wegr3j4y01qb363" `

  - ` errors `: type ` array ` — Validation problems, one per field (`invalid_request` and the other codes that list `errors`).

    - ` array item `: type ` object ` — One validation problem.

      - Required fields: ` pointer `, ` detail `

      - ` pointer `: type ` string ` — Where the problem is: a JSON pointer into the request body (`/url`, `/steps/0/uses`), or `#query/<name>`, `#path/<name>` or `#header/<name>` for parameters. 

        - example: ` "/url" `

      - ` detail `: type ` string ` — What is wrong there.

        - example: ` "must be an absolute http or https URL" `

  - ` reason `: type ` string ` — Finer-grained cause for codes that document one (`unauthorized`, `forbidden`, `egress_denied`, `upstream_unreachable`, …).

  - ` required_scope `: type ` string ` — The scope that was missing (`forbidden` with `reason: scope`).

  - ` retry_after_s `: type ` integer ` — Same value as the `Retry-After` header, for clients that only read the body.

    - minimum: ` 0 `

  - ` limit `: type ` object ` — The limit an error refers to. IDs and current values are listed by `GET /v1/limits`.

    - Required fields: ` id `, ` limit `, ` unit `

    - ` id `: type ` string ` — Limit ID, such as `vision.scrape.rpm` or `sandboxes.concurrent`.

      - example: ` "vision.scrape.rpm" `

    - ` limit `: type ` number ` — The limit's value.

    - ` unit `: type ` string ` — What the limit counts, such as `requests`, `sandboxes`, `vcpu` or `MiB`.

    - ` window_s `: type ` integer ` — Window length in seconds for rate limits and quotas.

    - ` current `: type ` number ` — Current usage against the limit, when known.

  - ` current_status `: type ` string ` — The object's current status, for state conflicts such as `sandbox_not_running`.

  - ` upstream_status `: type ` integer ` — The HTTP status the upstream returned (`upstream_error`, `action_output_invalid`).

  - ` step `: type ` string ` — The failed step, as a step ID (routines), an index (`act`) or a path such as `beats/2/do/0` (render).

  - ` pack_error `: type ` object ` — The error a pack's error mapping chose (`upstream_error` from pack actions).

    - Required fields: ` code `, ` message `, ` retryable `

    - ` code `: type ` string `

    - ` message `: type ` string `

    - ` retryable `: type ` boolean `

Response header ` x-request-id ` — The request ID (`req_…`). It is the `instance` of any problem and the key for `GET /v1/requests/{request_id}`.

- ` value `: type ` string `

  - pattern: ` "^req_[0-9a-hjkmnp-tv-z]{26}$" `

Response header ` Server-Timing ` — Phase durations in milliseconds (W3C Server Timing); the handler's phases break the request down. For a
response whose body size is known, `total` runs from reading the request head to writing the response head.
Streaming responses (event streams, WebSockets, chunked bodies) carry no `total` here: they report their
final phases in the terminal event (`job.succeeded`, `job.failed`, `job.canceled`) or the final job. The
time from the first request byte to the last response byte is recorded in the node's metrics and request
log (`GET /v1/requests/{request_id}`). The edge prepends `edge_auth` and `edge_upstream`.


- ` value `: type ` string `

Response header ` Retry-After ` — Seconds to wait before retrying or polling again.

- ` value `: type ` integer `

  - minimum: ` 0 `

Response header ` RateLimit-Limit ` — Requests allowed in the current window for the limit that applies to this operation.

- ` value `: type ` integer `

Response header ` RateLimit-Remaining ` — Requests left in the current window.

- ` value `: type ` integer `

Response header ` RateLimit-Reset ` — Seconds until the current window resets.

- ` value `: type ` integer `

Response header ` RateLimit-Policy ` — The applied policy as `<limit>;w=<window seconds>;name="<limit id>"` (limit IDs are listed by `GET /v1/limits`).

- ` value `: type ` string `

Example:

```json
{
  "type": "https://docs.beta.b3os.org/errors#rate_limited",
  "title": "Rate limited",
  "status": 429,
  "code": "rate_limited",
  "detail": "60 scrapes per minute allowed; retry in 12 seconds",
  "instance": "req_01m5t4yg394wegr3j4y01qb363",
  "retry_after_s": 12,
  "limit": {
    "id": "vision.scrape.rpm",
    "limit": 60,
    "unit": "requests",
    "window_s": 60,
    "current": 60
  }
}
```

### ` 500 ` — Something failed inside B3OS (`internal`). Retry with backoff.

Content type: ` application/problem+json `

- ` value `: type ` object ` — An RFC 9457 problem. `code` is stable and listed in the errors catalog; `type` links to its entry. `detail` is human-readable and may change. Extension members appear only for the codes that document them; ignore members you do not recognize. 

  - Required fields: ` type `, ` title `, ` status `, ` code `, ` detail `

  - ` type `: type ` string `; format ` uri ` — `https://docs.beta.b3os.org/errors#<code>`.

    - example: ` "https://docs.beta.b3os.org/errors#invalid_request" `

  - ` title `: type ` string ` — Short summary of the problem type.

  - ` status `: type ` integer ` — The HTTP status code, repeated for convenience.

    - minimum: ` 400 `

    - maximum: ` 599 `

  - ` code `: type ` string ` — Stable machine-readable error code from the errors catalog.

    - pattern: ` "^[a-z][a-z0-9_]*$" `

  - ` detail `: type ` string ` — Explanation of this occurrence. Never contains secrets.

  - ` instance `: type ` string ` — The request ID (`req_…`) of the request that failed. Include it when you contact support.

    - example: ` "req_01m5t4yg394wegr3j4y01qb363" `

  - ` errors `: type ` array ` — Validation problems, one per field (`invalid_request` and the other codes that list `errors`).

    - ` array item `: type ` object ` — One validation problem.

      - Required fields: ` pointer `, ` detail `

      - ` pointer `: type ` string ` — Where the problem is: a JSON pointer into the request body (`/url`, `/steps/0/uses`), or `#query/<name>`, `#path/<name>` or `#header/<name>` for parameters. 

        - example: ` "/url" `

      - ` detail `: type ` string ` — What is wrong there.

        - example: ` "must be an absolute http or https URL" `

  - ` reason `: type ` string ` — Finer-grained cause for codes that document one (`unauthorized`, `forbidden`, `egress_denied`, `upstream_unreachable`, …).

  - ` required_scope `: type ` string ` — The scope that was missing (`forbidden` with `reason: scope`).

  - ` retry_after_s `: type ` integer ` — Same value as the `Retry-After` header, for clients that only read the body.

    - minimum: ` 0 `

  - ` limit `: type ` object ` — The limit an error refers to. IDs and current values are listed by `GET /v1/limits`.

    - Required fields: ` id `, ` limit `, ` unit `

    - ` id `: type ` string ` — Limit ID, such as `vision.scrape.rpm` or `sandboxes.concurrent`.

      - example: ` "vision.scrape.rpm" `

    - ` limit `: type ` number ` — The limit's value.

    - ` unit `: type ` string ` — What the limit counts, such as `requests`, `sandboxes`, `vcpu` or `MiB`.

    - ` window_s `: type ` integer ` — Window length in seconds for rate limits and quotas.

    - ` current `: type ` number ` — Current usage against the limit, when known.

  - ` current_status `: type ` string ` — The object's current status, for state conflicts such as `sandbox_not_running`.

  - ` upstream_status `: type ` integer ` — The HTTP status the upstream returned (`upstream_error`, `action_output_invalid`).

  - ` step `: type ` string ` — The failed step, as a step ID (routines), an index (`act`) or a path such as `beats/2/do/0` (render).

  - ` pack_error `: type ` object ` — The error a pack's error mapping chose (`upstream_error` from pack actions).

    - Required fields: ` code `, ` message `, ` retryable `

    - ` code `: type ` string `

    - ` message `: type ` string `

    - ` retryable `: type ` boolean `

Response header ` x-request-id ` — The request ID (`req_…`). It is the `instance` of any problem and the key for `GET /v1/requests/{request_id}`.

- ` value `: type ` string `

  - pattern: ` "^req_[0-9a-hjkmnp-tv-z]{26}$" `

Response header ` Server-Timing ` — Phase durations in milliseconds (W3C Server Timing); the handler's phases break the request down. For a
response whose body size is known, `total` runs from reading the request head to writing the response head.
Streaming responses (event streams, WebSockets, chunked bodies) carry no `total` here: they report their
final phases in the terminal event (`job.succeeded`, `job.failed`, `job.canceled`) or the final job. The
time from the first request byte to the last response byte is recorded in the node's metrics and request
log (`GET /v1/requests/{request_id}`). The edge prepends `edge_auth` and `edge_upstream`.


- ` value `: type ` string `

Example:

```json
{
  "type": "https://docs.beta.b3os.org/errors#internal",
  "title": "Internal error",
  "status": 500,
  "code": "internal",
  "detail": "internal error",
  "instance": "req_01m5t4yg394wegr3j4y01qb363"
}
```

### ` 503 ` — The node or the product is not available right now (`node_unavailable`, `product_unavailable`, `capacity_unavailable`).

Content type: ` application/problem+json `

- ` value `: type ` object ` — An RFC 9457 problem. `code` is stable and listed in the errors catalog; `type` links to its entry. `detail` is human-readable and may change. Extension members appear only for the codes that document them; ignore members you do not recognize. 

  - Required fields: ` type `, ` title `, ` status `, ` code `, ` detail `

  - ` type `: type ` string `; format ` uri ` — `https://docs.beta.b3os.org/errors#<code>`.

    - example: ` "https://docs.beta.b3os.org/errors#invalid_request" `

  - ` title `: type ` string ` — Short summary of the problem type.

  - ` status `: type ` integer ` — The HTTP status code, repeated for convenience.

    - minimum: ` 400 `

    - maximum: ` 599 `

  - ` code `: type ` string ` — Stable machine-readable error code from the errors catalog.

    - pattern: ` "^[a-z][a-z0-9_]*$" `

  - ` detail `: type ` string ` — Explanation of this occurrence. Never contains secrets.

  - ` instance `: type ` string ` — The request ID (`req_…`) of the request that failed. Include it when you contact support.

    - example: ` "req_01m5t4yg394wegr3j4y01qb363" `

  - ` errors `: type ` array ` — Validation problems, one per field (`invalid_request` and the other codes that list `errors`).

    - ` array item `: type ` object ` — One validation problem.

      - Required fields: ` pointer `, ` detail `

      - ` pointer `: type ` string ` — Where the problem is: a JSON pointer into the request body (`/url`, `/steps/0/uses`), or `#query/<name>`, `#path/<name>` or `#header/<name>` for parameters. 

        - example: ` "/url" `

      - ` detail `: type ` string ` — What is wrong there.

        - example: ` "must be an absolute http or https URL" `

  - ` reason `: type ` string ` — Finer-grained cause for codes that document one (`unauthorized`, `forbidden`, `egress_denied`, `upstream_unreachable`, …).

  - ` required_scope `: type ` string ` — The scope that was missing (`forbidden` with `reason: scope`).

  - ` retry_after_s `: type ` integer ` — Same value as the `Retry-After` header, for clients that only read the body.

    - minimum: ` 0 `

  - ` limit `: type ` object ` — The limit an error refers to. IDs and current values are listed by `GET /v1/limits`.

    - Required fields: ` id `, ` limit `, ` unit `

    - ` id `: type ` string ` — Limit ID, such as `vision.scrape.rpm` or `sandboxes.concurrent`.

      - example: ` "vision.scrape.rpm" `

    - ` limit `: type ` number ` — The limit's value.

    - ` unit `: type ` string ` — What the limit counts, such as `requests`, `sandboxes`, `vcpu` or `MiB`.

    - ` window_s `: type ` integer ` — Window length in seconds for rate limits and quotas.

    - ` current `: type ` number ` — Current usage against the limit, when known.

  - ` current_status `: type ` string ` — The object's current status, for state conflicts such as `sandbox_not_running`.

  - ` upstream_status `: type ` integer ` — The HTTP status the upstream returned (`upstream_error`, `action_output_invalid`).

  - ` step `: type ` string ` — The failed step, as a step ID (routines), an index (`act`) or a path such as `beats/2/do/0` (render).

  - ` pack_error `: type ` object ` — The error a pack's error mapping chose (`upstream_error` from pack actions).

    - Required fields: ` code `, ` message `, ` retryable `

    - ` code `: type ` string `

    - ` message `: type ` string `

    - ` retryable `: type ` boolean `

Response header ` x-request-id ` — The request ID (`req_…`). It is the `instance` of any problem and the key for `GET /v1/requests/{request_id}`.

- ` value `: type ` string `

  - pattern: ` "^req_[0-9a-hjkmnp-tv-z]{26}$" `

Response header ` Server-Timing ` — Phase durations in milliseconds (W3C Server Timing); the handler's phases break the request down. For a
response whose body size is known, `total` runs from reading the request head to writing the response head.
Streaming responses (event streams, WebSockets, chunked bodies) carry no `total` here: they report their
final phases in the terminal event (`job.succeeded`, `job.failed`, `job.canceled`) or the final job. The
time from the first request byte to the last response byte is recorded in the node's metrics and request
log (`GET /v1/requests/{request_id}`). The edge prepends `edge_auth` and `edge_upstream`.


- ` value `: type ` string `

Response header ` Retry-After ` — Seconds to wait before retrying or polling again.

- ` value `: type ` integer `

  - minimum: ` 0 `

Example:

```json
{
  "type": "https://docs.beta.b3os.org/errors#node_unavailable",
  "title": "Node unavailable",
  "status": 503,
  "code": "node_unavailable",
  "detail": "Node n1 is not reachable; retry in 5 seconds",
  "instance": "req_01m5t4yg394wegr3j4y01qb363",
  "retry_after_s": 5
}
```

## Request examples

### cURL

```curl
curl -X GET 'https://beta-api.b3os.org/v1/render/backgrounds' \
  -H 'Authorization: Bearer YOUR_API_TOKEN'
```

### JavaScript

```javascript
const response = await fetch('https://beta-api.b3os.org/v1/render/backgrounds', {
  method: 'GET',
  headers: {
      "Authorization": "Bearer YOUR_API_TOKEN"
  }
});

const data = await response.json();
console.log(data);
```

### Python

```python
import requests

headers = {
    'Authorization': 'Bearer YOUR_API_TOKEN'
}

response = requests.get('https://beta-api.b3os.org/v1/render/backgrounds', headers=headers)
print(response.json())
```