# HTTP API Reference

This is the canonical public HTTP contract for Scriptorium.

## Service And Route

`POST /v1/runs` runs one prompt request and returns generated output,
validation, and metadata. The service has no built-in authentication or
authorization; deploy it behind appropriate network and authentication controls.

The service address and HTTP limits are configured as described in the
[configuration reference](config.md). `serve` invocation is defined in the
[CLI reference](cli.md).

Requests and responses are JSON objects. Requests are decoded as JSON regardless
of their `Content-Type`; successful JSON responses use
`Content-Type: application/json`. There are no query parameters.

## Request Limits

The configured request-body limit includes inline artifact bodies. The artifact
limit applies to HTTP `file` inputs. The response limit applies to the encoded
response, including the artifact body and optional raw output. A limit of zero
disables that limit.

A request body over its limit returns `413 request_too_large`; an oversized
file input returns `413 artifact_too_large`; an oversized encoded response
returns `413 response_too_large`.

## `POST /v1/runs`

### Request Body

The maintained [request example](../examples/http-run.json) is a complete
copyable shape. The smallest valid shape is:

```json
{
  "prompt_id": "generic.markdown_summary",
  "inputs": {
    "transcript": {"type": "inline", "body": "Source text"}
  }
}
```

| Field | Required | Meaning |
| --- | --- | --- |
| `prompt_id` | yes | Non-blank prompt ID. |
| `prompt_version` | no | Prompt version filter. |
| `profile_id` | no | Execution-profile ID; otherwise the prompt must set `default_profile`. |
| `inputs` | yes | Non-empty object mapping input names to references. |
| `vars` | no | Object mapping template-variable names to strings. |
| `model` | no | Runtime model-override object. |
| `include_raw_output` | no | Include `raw_model_output` when true. |

An input reference has a required `type` of `file` or `inline`. A `file`
reference requires `uri`; an `inline` reference requires `body`.

HTTP file references require a configured artifact root. Relative paths resolve
within that root. Absolute paths must be lexically within it; traversal outside
it is rejected with `400 artifact_not_allowed`. This lexical check does not
resolve symlinks: the operating system follows symlinks inside the root,
including ones that target outside it. Keep the root narrow and inaccessible to
untrusted writers.

The optional `model` object accepts `endpoint`, `model`, `temperature`,
`max_tokens`, `top_p`, `timeout_seconds`, `service_tier`,
`reasoning_effort`, `api_key_env`, and `extra_params`. Numeric ranges and
credential supply are defined by the [configuration reference](config.md).
Explicit zero values for the numeric fields are overrides; zero
`timeout_seconds` disables the outbound client timeout.

Raw API-key values are not accepted. `api_key` and any other unknown model
field cause `400 invalid_json`.

### Strict JSON

Request decoding rejects malformed JSON, unknown fields at every request level,
and trailing JSON tokens with `400 invalid_json`. A blank `prompt_id` or
empty `inputs` object returns `400 invalid_request`.

### Success Response

A completed run returns `200 OK`, including when generated content fails its
validation contract. The response contains:

- `artifact`: `name`, `content_type`, `body`, `size`, `hash`, and
  optional `uri`;
- `validation`: `status`, `mode`, `repair_attempts`, `is_valid`, plus
  optional `errors` and `schema_path`;
- `metadata`: run, prompt, rendered-prompt, profile, model, input-hash, usage,
  timing, validation, and repair-attempt metadata; and
- optional `raw_model_output` when requested.

`metadata.model_params` has `endpoint`, `model`, `temperature`,
`max_tokens`, `top_p`, and `timeout_seconds`, plus optional
`service_tier`, `reasoning_effort`, `api_key_env`, and `extra_params`.
`metadata.usage` always includes `prompt_tokens`, `completion_tokens`,
`total_tokens`, `cached_tokens`, and `cache_write_tokens`; unavailable
cache usage is reported as zero.

A validation failure has `validation.status: "failed"`, `is_valid: false`,
and any available diagnostic errors, while still returning the artifact and
metadata.

## Error Responses

Errors have this shape:

```json
{"error":{"code":"invalid_request","message":"prompt_id is required"}}
```

Messages are concise and do not expose wrapped internal causes.

| Status | Code | Meaning |
| --- | --- | --- |
| `400` | `invalid_json` | Malformed JSON, unknown field, or trailing JSON. |
| `400` | `invalid_request` | Missing or invalid request data or runtime override. |
| `400` | `profile_required` | No profile ID and no prompt default profile. |
| `400` | `prompt_load_failed` | Prompt definition failed to load. |
| `400` | `profile_load_failed` | Profile failed to load. |
| `400` | `artifact_not_allowed` | HTTP file input is disabled or outside the artifact root. |
| `400` | `artifact_read_failed` | Input artifact is invalid or cannot be read. |
| `400` | `prompt_render_failed` | Prompt template rendering failed. |
| `400` | `api_key_env_missing` | The selected credential environment variable is unset or empty. |
| `404` | `not_found` | Route does not exist. |
| `404` | `prompt_not_found` | Prompt ID or version does not exist. |
| `404` | `profile_not_found` | Profile ID does not exist. |
| `405` | `method_not_allowed` | The route does not accept the method. |
| `413` | `request_too_large` | Encoded request exceeds its limit. |
| `413` | `artifact_too_large` | File input exceeds its limit. |
| `413` | `response_too_large` | Encoded response exceeds its limit. |
| `500` | `validation_runtime_failed` | Schema or validator runtime failure. |
| `500` | `internal_error` | Unclassified server failure. |
| `502` | `llm_failed` | Outbound model request failed. |

## Retry And Idempotency

Scriptorium provides no idempotency keys, pagination, caching headers, or rate
limits. Clients may retry transport failures or `5xx` responses only when
their workflow tolerates another model call: a retry can produce different
output and incur another provider request.