> ## Documentation Index > Fetch the complete documentation index at: https://modem.dev/docs/llms.txt > Use this file to discover all available pages before exploring further. # Get history > Get change history for a topic. Returns audit trail of modifications with user attribution. ## OpenAPI ````yaml /api-reference/openapi.json get /topics/{topicId}/history openapi: 3.1.1 info: description: >- The public Modem API. Authenticate with an organization API key: `Authorization: Bearer modem_…`. title: Modem API version: 1.0.0 servers: - description: Production url: https://api.modem.dev/v1 security: - bearerAuth: [] paths: /topics/{topicId}/history: get: tags: - Topics summary: Get history description: >- Get change history for a topic. Returns audit trail of modifications with user attribution. operationId: topics.getHistory parameters: - in: path name: topicId required: true schema: anyOf: - format: uuid type: string - format: uuid type: string - allowEmptyValue: true allowReserved: true explode: true in: query name: changedByFilter required: false schema: description: >- Filter by actor type. Defaults to user and agent changes (excludes system). items: description: >- Actor type that initiated the change: system (internal/cascading), agent (AI), or user (manual). enum: - agent - system - user title: Changed By Type type: string title: Changed By Filter type: array style: deepObject - allowEmptyValue: true allowReserved: true in: query name: limit required: false schema: default: 20 description: Maximum number of history records to return (default 20, max 50). exclusiveMinimum: 0 maximum: 50 title: Limit type: integer responses: '200': content: application/json: schema: properties: actions: items: properties: actionAt: format: date-time type: string actionType: description: >- Semantic category of the action taken: started (a discrete unit of work was initiated, e.g. a PR was opened — per-artifact, not a topic-level state), merged (a code change was integrated into a canonical branch — NOT the same as deployed/shipped/released), resolved (a tracked task was completed positively, e.g. issue closed as completed), dismissed (a task was closed as wontfix / not pursued). User-initiated rows (created via dashboard, agent MCP tool, or direct API call) use the same enum values as auto rows — origin is encoded in metadata.source. enum: - dismissed - merged - resolved - started title: Topic Action Type type: string createdByUser: anyOf: - properties: id: anyOf: - type: string - type: string image: anyOf: - type: string - type: 'null' description: Optional URL to the user avatar image. title: Image name: description: Human-readable name of the user. title: Name type: string required: - id - image - name type: object - type: 'null' externalLink: anyOf: - properties: authorLogin: type: string createdAt: format: date-time type: string draft: type: boolean linkType: const: github_pull_request merged: type: boolean number: type: integer state: enum: - closed - open type: string title: type: string url: format: uri type: string required: - authorLogin - draft - linkType - merged - number - state - title - url type: object - properties: linkType: const: github_issue number: type: integer title: type: string url: format: uri type: string required: - linkType - number - title - url type: object - properties: linkType: const: none required: - linkType type: object id: description: Unique identifier for the action record. format: uuid title: Action ID type: string metadata: {} note: anyOf: - type: string - type: 'null' required: - actionType - createdByUser - externalLink - id - note type: object type: array history: items: properties: changedAt: format: date-time type: string changedBy: description: >- Actor type that initiated the change: system (internal/cascading), agent (AI), or user (manual). enum: - agent - system - user title: Changed By Type type: string changes: additionalProperties: {} propertyNames: type: string type: object id: anyOf: - format: uuid type: string - format: uuid type: string operation: description: >- Type of database operation that triggered the history record. enum: - DELETE - INSERT - UPDATE title: Topic History Operation type: string previousValues: anyOf: - additionalProperties: {} propertyNames: type: string type: object - type: 'null' user: anyOf: - properties: id: anyOf: - type: string - type: string image: anyOf: - type: string - type: 'null' description: Optional URL to the user avatar image. title: Image name: description: Human-readable name of the user. title: Name type: string required: - id - image - name type: object - type: 'null' required: - changedBy - changes - id - operation - previousValues - user type: object type: array mergedInto: anyOf: - properties: id: type: string mergedAt: format: date-time type: string targetTopic: anyOf: - properties: id: type: string title: type: string required: - id - title type: object - type: 'null' user: anyOf: - properties: id: anyOf: - type: string - type: string image: anyOf: - type: string - type: 'null' description: Optional URL to the user avatar image. title: Image name: description: Human-readable name of the user. title: Name type: string required: - id - image - name type: object - type: 'null' required: - id - targetTopic - user type: object - type: 'null' merges: items: properties: id: type: string mergedAt: format: date-time type: string sourceTopics: items: properties: id: type: string title: type: string required: - id - title type: object type: array user: anyOf: - properties: id: anyOf: - type: string - type: string image: anyOf: - type: string - type: 'null' description: Optional URL to the user avatar image. title: Image name: description: Human-readable name of the user. title: Name type: string required: - id - image - name type: object - type: 'null' required: - id - sourceTopics - user type: object type: array totalCount: type: number required: - actions - history - mergedInto - merges - totalCount type: object description: OK '400': content: application/json: schema: $ref: '#/components/schemas/Error' description: Invalid request (validation failed). '401': content: application/json: schema: $ref: '#/components/schemas/Error' description: Missing or invalid API key. '403': content: application/json: schema: $ref: '#/components/schemas/Error' description: The API key does not have access to this resource. '404': content: application/json: schema: $ref: '#/components/schemas/Error' description: The requested resource was not found. '429': content: application/json: schema: $ref: '#/components/schemas/Error' description: Rate limit exceeded. '500': content: application/json: schema: $ref: '#/components/schemas/Error' description: Internal server error. components: schemas: Error: properties: code: description: Machine-readable error code, e.g. `NOT_FOUND`. examples: - NOT_FOUND type: string data: description: Optional structured error details. defined: description: True if the error was declared in the procedure contract. type: boolean message: description: Human-readable error message. type: string status: description: HTTP status code. examples: - 404 type: integer required: - code - defined - message - status type: object securitySchemes: bearerAuth: description: Organization API key (`modem_…`). scheme: bearer type: http ````