> ## Documentation Index > Fetch the complete documentation index at: https://docs.firedrill.run/llms.txt > Use this file to discover all available pages before exploring further. # Read a retained value chunk > Requires `read`. Returns a bounded UTF-8 JSON chunk of an exact retained value. eventId is required only for source=event; checkId is required only for check_actual/check_expected. Continue with nextOffset and the returned digest; a changed digest conflicts. These reads do not execute or reassess the target. ## OpenAPI ````yaml /api-reference/openapi.json get /v1/runs/{runId}/value openapi: 3.1.0 info: title: Firedrill API version: '2026-10-14' description: >- Authenticated simulation coordination, retained evidence and controlled Tools. Your customer-owned runner executes the target. This reference covers the documented JSON workflows; Tool-native HTTP routes and MCP methods are discovered from the selected Tool. Structural schemas do not replace canonical validation or capability checks. servers: - url: https://api.firedrill.run security: - FiredrillCredential: [] tags: - name: discovery description: Capabilities, authority and structural authoring schemas. - name: projects description: Projects and their logical environment. - name: simulations description: Preparation, queued batches and cancellation. - name: runs description: Individual recorded executions. - name: reports description: Retained observations, distributions and descriptive comparisons. - name: assessment description: Optional semantic assessment and authored scenario ranking. - name: evidence description: Authenticated captured files. - name: runner-protocol description: Advanced customer-runner coordination; native SDKs manage this protocol. - name: scenarios description: Immutable retained versions of repository-authored scenarios. - name: credentials description: Expiring scoped CI credentials. - name: authentication description: Human-approved sign-in boundaries. - name: tools description: Tool releases, data, instances and observations. - name: tool-connections description: Bounded target/manual grants, separate from control authority. - name: tool-lifecycle description: Epoch-fenced reusable Tool actions and exact-key recovery. paths: /v1/runs/{runId}/value: get: tags: - reports summary: Read a retained value chunk description: >- Requires `read`. Returns a bounded UTF-8 JSON chunk of an exact retained value. eventId is required only for source=event; checkId is required only for check_actual/check_expected. Continue with nextOffset and the returned digest; a changed digest conflicts. These reads do not execute or reassess the target. operationId: runs_get_value parameters: - name: runId in: path required: true schema: type: string minLength: 1 maxLength: 160 - name: source in: query required: true schema: type: string enum: - output - input - scenario - configuration - target - assessment - event - check_actual - check_expected - name: pointer in: query required: false schema: type: string description: RFC 6901 pointer into the selected retained value. - name: eventId in: query required: false schema: type: string - name: checkId in: query required: false schema: type: string - name: offset in: query required: false schema: type: integer minimum: 0 - name: limit in: query required: false schema: type: integer minimum: 256 maximum: 32768 default: 8192 - name: sha256 in: query required: false schema: type: string pattern: ^[a-f0-9]{64}$ description: >- Required for continuation offsets; use the digest from the first chunk. - name: x-fd-read-scope-version in: header required: false schema: type: string const: 2026-10-16-read-scope.1 description: >- Send all three selected-read headers together. The response echoes the confirmed selection. - name: x-fd-read-project-id in: header required: false schema: type: string description: >- Your selected project. A resource outside the selected context returns 409. - name: x-fd-read-environment-id in: header required: false schema: type: string description: Your selected environment. These headers never grant authority. responses: '200': description: The retained resource or operation response. content: application/json: schema: $ref: '#/components/schemas/RetainedValueChunk' headers: x-fd-read-scope-version: description: >- Send all three selected-read headers together. The response echoes the confirmed selection. schema: type: string const: 2026-10-16-read-scope.1 x-fd-read-project-id: description: >- Your selected project. A resource outside the selected context returns 409. schema: type: string x-fd-read-environment-id: description: Your selected environment. These headers never grant authority. schema: type: string '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/Forbidden' '404': $ref: '#/components/responses/NotFound' '409': $ref: '#/components/responses/Conflict' '410': $ref: '#/components/responses/Gone' '413': $ref: '#/components/responses/PayloadTooLarge' '415': $ref: '#/components/responses/UnsupportedMediaType' '422': $ref: '#/components/responses/InvalidInput' '429': $ref: '#/components/responses/Capacity' '500': $ref: '#/components/responses/Internal' '503': $ref: '#/components/responses/Unavailable' components: schemas: RetainedValueChunk: type: object properties: schemaVersion: type: string const: 2026-10-15-retained-value.1 resource: type: object properties: kind: type: string enum: - batch - run id: type: string required: - kind - id encoding: type: string const: utf-8 serialization: type: string const: json offset: type: number returnedBytes: type: number text: type: string nextOffset: anyOf: - type: 'null' - type: number complete: type: boolean source: $ref: '#/components/schemas/RetainedValueSource' pointer: type: string eventId: anyOf: - type: string checkId: anyOf: - type: string valueType: $ref: '#/components/schemas/RetainedValueType' totalBytes: type: number sha256: type: string readPath: type: string required: - schemaVersion - resource - encoding - serialization - offset - returnedBytes - text - nextOffset - complete - source - pointer - valueType - totalBytes - sha256 - readPath RetainedValueSource: type: string enum: - output - input - target - scenario - configuration - recipe - assessment - event - check_actual - check_expected RetainedValueType: type: string enum: - string - number - boolean - object - 'null' - array ApiError: type: object properties: error: type: object properties: code: type: string message: type: string repair: type: string requestId: type: string details: anyOf: - type: 'null' - type: string - type: number - type: boolean const: false - type: boolean const: true - type: array items: $ref: '#/components/schemas/JsonValue' - type: object properties: {} required: [] additionalProperties: $ref: '#/components/schemas/JsonValue' validation: anyOf: - $ref: '#/components/schemas/ValidationDiagnostics' required: - code - message - repair - requestId required: - error JsonValue: description: >- Any JSON value: null, boolean, finite number, string, array or object. The request transport must contain valid JSON; canonical validation rejects nonfinite numbers. ValidationDiagnostics: type: object properties: issues: type: array items: $ref: '#/components/schemas/ValidationIssue' totalIssues: type: number omittedIssues: type: number required: - issues - totalIssues - omittedIssues ValidationIssue: type: object properties: path: type: array items: anyOf: - type: string - type: number code: type: string message: type: string pathTruncated: anyOf: - type: boolean const: true required: - path - code - message responses: BadRequest: description: >- Malformed request or missing operation key. Repair the input before retrying. content: application/json: schema: $ref: '#/components/schemas/ApiError' Unauthorized: description: >- Missing, expired or revoked authority. Complete supported sign-in or use an authorized credential. content: application/json: schema: $ref: '#/components/schemas/ApiError' Forbidden: description: >- The current capability, actor, audience or ownership grant does not allow this operation. content: application/json: schema: $ref: '#/components/schemas/ApiError' NotFound: description: The exact resource is unavailable under the current authority and scope. content: application/json: schema: $ref: '#/components/schemas/ApiError' Conflict: description: >- Selected context, epoch, revision, lease or saved operation intent conflicts; inspect retained state. content: application/json: schema: $ref: '#/components/schemas/ApiError' Gone: description: >- Retained content is expired, deleted or unavailable under its retention fence. Metadata is not a replacement payload. content: application/json: schema: $ref: '#/components/schemas/ApiError' PayloadTooLarge: description: >- Request, response or retained-resource size exceeds this operation’s enforced bound. content: application/json: schema: $ref: '#/components/schemas/ApiError' UnsupportedMediaType: description: Send the documented JSON or exact artifact media type. content: application/json: schema: $ref: '#/components/schemas/ApiError' InvalidInput: description: >- Input failed canonical validation. Inspect error.validation and repair the indicated fields. content: application/json: schema: $ref: '#/components/schemas/ApiError' Capacity: description: >- Bounded capacity or resource admission rejected the operation. Inspect retained work before retrying. content: application/json: schema: $ref: '#/components/schemas/ApiError' Internal: description: >- The service could not complete the request. Inspect retained state before exact-key recovery. content: application/json: schema: $ref: '#/components/schemas/ApiError' Unavailable: description: >- A required service, provider or authority check is unavailable. Existing evidence remains separate from this failure. content: application/json: schema: $ref: '#/components/schemas/ApiError' securitySchemes: FiredrillCredential: type: http scheme: bearer description: >- Opaque Firedrill interactive or scoped machine credential. The CLI handles human-approved login; CI stores its scoped credential as FIREDRILL_TOKEN. Capabilities and project/environment ownership are rechecked at use. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.