> ## Documentation Index
> Fetch the complete documentation index at: https://docs.seomator.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Days the measurement changed

> Marks for trend charts. One kind is the day an assistant’s main model changed: the model of more than half of its answers that day moved from one known model to another. A day without such a model is skipped, and so are unknown models. The other kind is the days prompts were added or archived after tracking started. With `promptId`, only the model changes in that prompt’s answers are returned.



## OpenAPI

````yaml https://api.seomator.com/openapi.json get /v1/projects/{id}/trend-markers
openapi: 3.1.0
info:
  title: SEOmator API
  version: 0.1.0
servers:
  - url: https://api.seomator.com
security: []
paths:
  /v1/projects/{id}/trend-markers:
    get:
      tags:
        - ai visibility
      summary: Days the measurement changed
      description: >-
        Marks for trend charts. One kind is the day an assistant’s main model
        changed: the model of more than half of its answers that day moved from
        one known model to another. A day without such a model is skipped, and
        so are unknown models. The other kind is the days prompts were added or
        archived after tracking started. With `promptId`, only the model changes
        in that prompt’s answers are returned.
      parameters:
        - schema:
            type: string
            description: Project id (proj_…) or slug (the domain with dots as dashes).
          required: true
          description: Project id (proj_…) or slug (the domain with dots as dashes).
          name: id
          in: path
        - schema:
            type: string
            format: date
            description: First day (UTC)
          required: true
          description: First day (UTC)
          name: startDate
          in: query
        - schema:
            type: string
            format: date
            description: Last day (UTC)
          required: true
          description: Last day (UTC)
          name: endDate
          in: query
        - schema:
            type: string
            maxLength: 64
            description: Only model changes in the answers to this prompt
          required: false
          description: Only model changes in the answers to this prompt
          name: promptId
          in: query
      responses:
        '200':
          description: Markers
          content:
            application/json:
              schema:
                type: object
                properties:
                  markers:
                    type: array
                    items:
                      anyOf:
                        - type: object
                          properties:
                            date:
                              type: string
                              format: date
                            kind:
                              type: string
                              enum:
                                - model
                            assistant:
                              type: string
                            from:
                              type: string
                            to:
                              type: string
                          required:
                            - date
                            - kind
                            - assistant
                            - from
                            - to
                        - type: object
                          properties:
                            date:
                              type: string
                              format: date
                            kind:
                              type: string
                              enum:
                                - prompts
                            added:
                              type: integer
                            archived:
                              type: integer
                          required:
                            - date
                            - kind
                            - added
                            - archived
                    description: >-
                      Days the measurement itself changed: the main model of an
                      assistant (the model of more than half of its answers that
                      day) moved from one known model to another, or prompts
                      were added or archived. Sorted by date.
                required:
                  - markers
                additionalProperties: {}
        '400':
          description: Bad request
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '403':
          description: Forbidden
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '404':
          description: Not found
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
      security:
        - apiKey: []
components:
  schemas:
    Error:
      type: object
      properties:
        error:
          type: object
          properties:
            code:
              type: string
              enum:
                - bad_request
                - unauthorized
                - insufficient_credits
                - plan_limit
                - forbidden
                - not_found
                - conflict
                - rate_limit_exceeded
                - internal_server_error
                - service_unavailable
            message:
              type: string
            requestId:
              type: string
          required:
            - code
            - message
      required:
        - error
  securitySchemes:
    apiKey:
      type: apiKey
      in: header
      name: x-api-key

````

## Related topics

- [Insights: how often AI names your brand](https://docs.seomator.com/reports/insights.md)
- [Start, pause or change daily tracking](https://docs.seomator.com/api-reference/ai-visibility/start-pause-or-change-daily-tracking.md)
- [Frequently asked questions](https://docs.seomator.com/getting-started/faq.md)


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