> ## Documentation Index > Fetch the complete documentation index at: https://docs.errorbar.ai/llms.txt > Use this file to discover all available pages before exploring further. # Score a rollout group > Score up to 64 rollouts against a session's reward. Billing ids are namespaced `reward::` so a re-scored step is idempotent. Refusals are explicit: 402 `budget_exhausted` (the session's kill switch), 409 `held` (the anchor held the run — resume deliberately or ship the pinned step), 404 (unknown/foreign session), 422 (the reward no longer validates). An unparseable judge returns `grade: null` for that item: mask it, never zero it. ## OpenAPI ````yaml /openapi.json post /v1/reward/score openapi: 3.1.0 info: title: errorbar Management API description: >- The management API behind the improvement loop: capture and setup, request logs and datasets, grades (labels), judges (criteria), evals and deploy gates, fine-tuning and reinforcement learning, dedicated GPU endpoints, and model aliases and versions. Authenticated with a workspace API key (sk_sovereign_...). The inference API (chat, embeddings, rerank, responses) is OpenAI-compatible and documented separately. Responses are snake_case, list endpoints on the loop products use the {"object": "list", "data": [...]} envelope, and refusals use the same nested error shape the gateway emits: {"error": {"message", "type", "code"}}. Request bodies on the loop products (logs, labels, criteria, evals, datasets, aliases) are snake_case; the training and infrastructure products (fine-tuning, GRPO, environment tools, dedicated, model-version adoption) validate camelCase bodies, and each schema below says which it is. Endpoints that spend money require a key minted by a workspace owner or admin and return 403 otherwise. version: 1.0.0 servers: - url: https://gateway.errorbar.ai description: Production - url: https://www.errorbar.ai/api description: Control plane (also served at this base URL) security: - bearerAuth: [] tags: - name: Certified reward description: >- The certified reward for your own trainer: sessions with judge certificates, scoring with a ledger-true kill switch, and the mid-run anchor that holds a run when the reward diverges from an independent judge. paths: /v1/reward/score: post: tags: - Certified reward summary: Score a rollout group description: >- Score up to 64 rollouts against a session's reward. Billing ids are namespaced `reward::` so a re-scored step is idempotent. Refusals are explicit: 402 `budget_exhausted` (the session's kill switch), 409 `held` (the anchor held the run — resume deliberately or ship the pinned step), 404 (unknown/foreign session), 422 (the reward no longer validates). An unparseable judge returns `grade: null` for that item: mask it, never zero it. operationId: scoreReward requestBody: required: true content: application/json: schema: type: object required: - sessionId - items properties: sessionId: type: string step: type: string pattern: ^[A-Za-z0-9_.-]{1,40}$ description: Optimizer step tag; defaults to "s". items: type: array minItems: 1 maxItems: 64 items: $ref: '#/components/schemas/RewardItem' responses: '200': description: Scores in the order the server grouped them (match on request_id). content: application/json: schema: type: object properties: session_id: type: string scores: type: array items: $ref: '#/components/schemas/RewardScore' spend_micros: type: string criteria: type: array items: type: string '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '402': $ref: '#/components/responses/InsufficientBalance' '403': $ref: '#/components/responses/Forbidden' '404': $ref: '#/components/responses/NotFound' '409': description: >- The session is held by its anchor (`code: held`); the body names the pinned step. content: application/json: schema: $ref: '#/components/schemas/Error' components: schemas: RewardItem: type: object required: - requestId - conversation properties: requestId: type: string maxLength: 200 description: >- Your id for the rollout; re-sending the same (step, requestId) settles into the same ledger rows. conversation: type: string description: The prompt/conversation the policy answered. response: type: string description: Single-turn completion (omit when sending steps). steps: type: array maxItems: 200 items: type: object required: - role - content properties: role: type: string enum: - assistant - tool content: type: string source: type: string enum: - code - recorded - declared - simulated - flagged toolName: type: string description: >- Agentic sessions: the whole rollout as structured steps; the server renders and sanitises it through the same instrument trace calibration uses. sessionId: type: string description: >- The episode's errorbar environment session id (exec verifiers + attestation). RewardScore: type: object properties: request_id: type: string grade: type: - number - 'null' description: >- Composite grade in [0,1]: mean of judge P(pass) and 0/1 assertions. null = the judge could not parse a verdict — MASK the sample, never treat it as 0. verdict: type: string enum: - pass - fail - unparsed description: 'Strict read: every component passes.' sim_fraction: type: number raw_grade: type: number exec_unverified: type: boolean attested: type: boolean attestation_mismatch: type: boolean Error: type: object properties: error: type: object properties: message: type: string type: type: string description: >- invalid_request_error, insufficient_quota, rate_limit_error, or api_error. code: type: string description: >- Machine-stable cause, e.g. invalid_api_key, not_found, insufficient_permissions, precondition_failed. required: - message - type - code description: >- Every refusal — gateway and management API alike — uses this one envelope. responses: BadRequest: description: Malformed request or invalid field. content: application/json: schema: $ref: '#/components/schemas/Error' Unauthorized: description: Missing, malformed, or revoked API key. content: application/json: schema: $ref: '#/components/schemas/Error' example: error: message: Invalid API key type: invalid_request_error code: invalid_api_key InsufficientBalance: description: Your wallet can't cover the required prepaid runway. content: application/json: schema: $ref: '#/components/schemas/Error' example: error: message: >- Insufficient balance: deploying this endpoint requires at least 1h of runway. Top up and try again. type: insufficient_quota code: insufficient_balance Forbidden: description: The key lacks the required owner/admin permission. content: application/json: schema: $ref: '#/components/schemas/Error' NotFound: description: The resource does not exist in your workspace. content: application/json: schema: $ref: '#/components/schemas/Error' securitySchemes: bearerAuth: type: http scheme: bearer description: >- Your workspace API key, e.g. `sk_sovereign_...`, sent as `Authorization: Bearer `. ````