> ## Documentation Index > Fetch the complete documentation index at: https://docs.moonbounce.ai/llms.txt > Use this file to discover all available pages before exploring further. # Set what a decision decides, in one sentence > Stores one sentence, in plain language, on what the decision decides ('Decides whether a late delivery earns a refund.'), which reviewers read on the decision's review pages. Send only that sentence: it is stored and shown as written, so never paste policy text or the brief into it. `getDecision` and `listDecisions` read it back. It belongs to the whole organization, like the decision, so a test key and a production key share one value and the latest write wins; there is no history. `{"description": null}` clears it. It is not part of the structure and never changes `structure_hash` or anything evaluated. Always 200: `changed` is false, and nothing is written, when it already read that way. 404 DECISION_UNKNOWN when the decision doesn't exist (register a version first). An Idempotency-Key covers the body after trimming. ## OpenAPI ````yaml /openapi.json put /v1/decisions/{decision_id}/description openapi: 3.1.0 info: title: Moonbounce Decisions API version: 0.0.0 description: >- Moonbounce decisions: evaluate an item's state against a decision structure (System One questions, attributes you supply and aggregations over both), record feedback and import labeled examples, review a ranked queue, and improve the structure through suggestions that ship as code diffs, each with a preview (backtest) and an evidence label. **Authentication.** Send an API key as `Authorization: Bearer ` on every operation except `GET /health` and `POST /v1/validate`, and an upload's own `url` (`PUT /v1/uploads/{upload_id}/{token}`), which its token authorizes. Call the API from a server, never a browser: a key must not reach one, and the API sends no CORS headers. A key belongs to one organization and one environment: production, or test for a key with the `env:test` permission. Test traffic never counts as production traffic. **Requests.** JSON bodies (`Content-Type: application/json`) of at most 1 MB, parsed strictly: duplicate keys, lone surrogates, integers outside ±(2^53 - 1), `__proto__` keys, U+0000 and nesting deeper than 64 are a 400. A larger dataset, or a file you'd rather not paste, goes up as a file: `createUpload` answers a URL to PUT it to. **Retries.** Send an `Idempotency-Key` on every POST under /v1 that takes one (all but `POST /v1/validate`, `POST /v1/review/items/fill`, whose retry is another fill within the day's budget, and `createUpload`, whose retry is another upload). Keep it for the request's retries. The same key with the same request returns the first stored result, marked `Idempotent-Replayed: true`, for 24 hours (410 if that result was since deleted); with another request it is 422 IDEMPOTENCY_KEY_REUSED. Keys are scoped to the organization and environment across every operation, so use a fresh key per request. A request that failed before its result was stored runs again when retried. 429 and 503 under /v1 may carry `Retry-After` (seconds); a daily QUOTA_EXCEEDED cap instead names its reset time. **Lists.** A list answers one page: `{environment, items, next_cursor, has_more}` (named `Page`), in the order the operation states. Pass `next_cursor` back as `cursor`, with the same filters, while `has_more` is true; on the last page `next_cursor` is null. `limit` defaults to 50 and is at most 100, with these exceptions: cases go up to 200 a page (a run's batch; 50 with content), suggestions default to 20, since each carries its whole candidate structure and evidence, and the review queue (a reviewer's screen) defaults to 20, at most 50. **Errors.** Every error under /v1 is `{"error": {"type", "message", "reason"?, "param"?, "details"?}}` (ErrorBody); `GET /health` answers its own shape. Every response carries a `Request-Id` header. Rate limits apply per key, and per client IP for requests without a valid key; a 429 RATE_LIMITED carries `Retry-After`. servers: - url: https://api.moonbounce.ai description: Production security: [] tags: - name: Evaluate description: Run one item through a decision and read evaluations back. Start here. - name: Decisions description: >- Validate a decision file, register its versions, and read decisions and versions. - name: Feedback description: >- Say what the right answer was, import labeled examples, and read feedback and cases. - name: Suggestions description: Ask for a better version of a decision, and follow the improvement loop. - name: Uploads description: >- Send a dataset or structure file once, then name it in runs, imports and registrations. - name: Previews & tests description: >- Replay a structure change over past cases, and score a version over many items. - name: Models description: List the models a decision can run on and choose one. - name: Objective description: >- Set what a decision optimizes for, then judge runs and tune cuts against it. - name: Usage description: What a decision's model calls cost. - name: Account description: Identify your key, and check that the API is up. paths: /v1/decisions/{decision_id}/description: put: tags: - Decisions summary: Set what a decision decides, in one sentence description: >- Stores one sentence, in plain language, on what the decision decides ('Decides whether a late delivery earns a refund.'), which reviewers read on the decision's review pages. Send only that sentence: it is stored and shown as written, so never paste policy text or the brief into it. `getDecision` and `listDecisions` read it back. It belongs to the whole organization, like the decision, so a test key and a production key share one value and the latest write wins; there is no history. `{"description": null}` clears it. It is not part of the structure and never changes `structure_hash` or anything evaluated. Always 200: `changed` is false, and nothing is written, when it already read that way. 404 DECISION_UNKNOWN when the decision doesn't exist (register a version first). An Idempotency-Key covers the body after trimming. operationId: setDescription parameters: - schema: $ref: '#/components/schemas/DecisionId' required: true description: >- A name you choose for this decision, such as `refund-exception`: a lowercase letter, then up to 127 of `a-z 0-9 _ . -`. Unique in your organization and shared by its test and production keys. The first registration or evaluation under a new one creates the decision. name: decision_id in: path - schema: type: string minLength: 1 maxLength: 255 pattern: ^[\x20-\x7e]+$ description: >- Makes a retry safe. For 24 hours, the same key with the same request returns the first stored result (with Idempotent-Replayed: true); the same key with a different request is a 422 IDEMPOTENCY_KEY_REUSED. Keys are scoped to the organization and environment across every operation, so use a fresh key per request. A request that failed before its result was stored runs again when retried with its key. required: false description: >- Makes a retry safe. For 24 hours, the same key with the same request returns the first stored result (with Idempotent-Replayed: true); the same key with a different request is a 422 IDEMPOTENCY_KEY_REUSED. Keys are scoped to the organization and environment across every operation, so use a fresh key per request. A request that failed before its result was stored runs again when retried with its key. name: idempotency-key in: header requestBody: required: true content: application/json: examples: one_sentence: summary: One sentence on what the decision decides value: description: >- Decides whether a refund request is granted, escalated or denied. clear: summary: Clear it value: description: null schema: $ref: '#/components/schemas/DecisionDescriptionWrite' responses: '200': description: The description, changed or not headers: Idempotent-Replayed: schema: type: string enum: - 'true' description: >- Present and `true` when this is the stored result of an earlier request with the same Idempotency-Key. required: false description: >- Present and `true` when this is the stored result of an earlier request with the same Idempotency-Key. content: application/json: examples: stored: summary: The sentence, stored value: decision_id: refund-exception description: >- Decides whether a refund request is granted, escalated or denied. changed: true schema: $ref: '#/components/schemas/DecisionDescriptionWritten' '400': description: 'Invalid request: `param` names the field at fault when one applies' content: application/json: schema: $ref: '#/components/schemas/ErrorBody' '401': description: Missing or invalid API key (reason KEY_INVALID) content: application/json: schema: $ref: '#/components/schemas/ErrorBody' '403': description: The key may not do this content: application/json: schema: $ref: '#/components/schemas/ErrorBody' '404': description: Not found, or not visible to this key (reason DECISION_UNKNOWN) x-error-reasons: - DECISION_UNKNOWN content: application/json: schema: $ref: '#/components/schemas/ErrorBody' '410': description: >- The Idempotency-Key's first result was deleted, so it cannot be replayed content: application/json: schema: $ref: '#/components/schemas/ErrorBody' '413': description: The HTTP body exceeds 1 MB (reason BODY_TOO_LARGE) content: application/json: schema: $ref: '#/components/schemas/ErrorBody' '422': description: >- The request is well formed but cannot be processed (IDEMPOTENCY_KEY_REUSED requires a fresh key; REQUEST_TOO_LARGE requires a smaller request) content: application/json: schema: $ref: '#/components/schemas/ErrorBody' '429': description: >- RATE_LIMITED: retry after Retry-After seconds; QUOTA_EXCEEDED: details.reset_at gives the daily reset time (no Retry-After) headers: Retry-After: schema: type: string description: Seconds to wait before retrying, when waiting helps. required: false description: Seconds to wait before retrying, when waiting helps. content: application/json: schema: $ref: '#/components/schemas/ErrorBody' '503': description: >- Temporarily unavailable, with Retry-After (for example reason AUTH_UNAVAILABLE, ENGINE_UNAVAILABLE or STORE_UNAVAILABLE): retry with the same Idempotency-Key headers: Retry-After: schema: type: string description: Seconds to wait before retrying, when waiting helps. required: true description: Seconds to wait before retrying, when waiting helps. content: application/json: schema: $ref: '#/components/schemas/ErrorBody' security: - bearerAuth: - decisions:develop components: schemas: DecisionId: type: string pattern: ^[a-z][a-z0-9_.-]{0,127}$ description: >- A name you choose for this decision, such as `refund-exception`: a lowercase letter, then up to 127 of `a-z 0-9 _ . -`. Unique in your organization and shared by its test and production keys. The first registration or evaluation under a new one creates the decision. DecisionDescriptionWrite: type: object properties: description: anyOf: - $ref: '#/components/schemas/DecisionDescription' - type: 'null' description: The sentence. Null clears it. required: - description additionalProperties: false DecisionDescriptionWritten: type: object properties: decision_id: $ref: '#/components/schemas/DecisionIdOutput' description: anyOf: - $ref: '#/components/schemas/DecisionDescriptionOutput' - type: 'null' changed: type: boolean description: False when it already read that way, so nothing was written. required: - decision_id - description - changed ErrorBody: type: object properties: error: type: object properties: type: $ref: '#/components/schemas/ErrorType' reason: type: string pattern: ^[A-Z][A-Z0-9_]+$ description: >- Set where a caller can act on it, one of the reasons in the ErrorReason schema. New reasons may be added: treat an unknown one by the status and `type`. message: type: string description: For people; don't parse it. param: type: string description: >- The request field at fault, as a dotted path (`attribute_values.region`, `claims.1.value`). details: type: object properties: issues: type: array items: $ref: '#/components/schemas/ErrorIssue' additionalProperties: {} required: - type - message additionalProperties: true x-moonbounce-sdk-known-fields: true required: - error additionalProperties: true x-moonbounce-sdk-known-fields: true DecisionDescription: type: string minLength: 1 maxLength: 200 description: >- One sentence, in plain language, on what the decision decides, for the people reading it: 'Decides whether a late delivery earns a refund.' 1 to 200 characters on one line, trimmed. Never part of the structure hash. example: Decides whether a late delivery earns a refund. DecisionIdOutput: type: string pattern: ^[a-z][a-z0-9_.-]{0,127}$ description: >- A name you choose for this decision, such as `refund-exception`: a lowercase letter, then up to 127 of `a-z 0-9 _ . -`. Unique in your organization and shared by its test and production keys. The first registration or evaluation under a new one creates the decision. DecisionDescriptionOutput: type: string minLength: 1 maxLength: 200 description: >- One sentence, in plain language, on what the decision decides, for the people reading it: 'Decides whether a late delivery earns a refund.' 1 to 200 characters on one line, trimmed. Never part of the structure hash. example: Decides whether a late delivery earns a refund. ErrorType: type: string enum: - invalid_request - authentication - permission_denied - not_found - conflict - rate_limited - engine_failed - unavailable - internal ErrorIssue: type: object properties: param: type: string code: type: string pattern: ^[A-Z][A-Z0-9_]+$ description: >- Stable, extensible issue code; unknown codes still have a parameter and human-readable message. message: type: string required: - param - code - message additionalProperties: true x-moonbounce-sdk-known-fields: true securitySchemes: bearerAuth: type: http scheme: bearer description: >- An API key, sent as `Authorization: Bearer `. Each operation lists the scope its key needs: `decisions:evaluate` (evaluate and read evaluations), `decisions:feedback` (your app's feedback) or `decisions:develop` (everything else, including owner feedback and the review queue). An operation listing no scope takes any scoped key. A key with no scope, or without the operation's, gets 403 INSUFFICIENT_SCOPE. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.