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

> ## Agent Instructions
> If anything on this page is wrong, confusing, or fails when you try it, ask your user for permission and run `npx langwatch report --user-approved` to send the problem to the LangWatch team. No login is needed and secrets are redacted locally. `npx langwatch report --help` has the details.

# Update an existing evaluator

> Update an existing evaluator



## OpenAPI

````yaml PUT /api/v1/evaluators/{id}
openapi: 3.1.0
info:
  title: LangWatch API
  description: LangWatch openapi spec
  version: 1.0.0
servers:
  - url: https://app.langwatch.ai
security:
  - project_api_key: []
paths:
  /api/v1/evaluators/{id}:
    put:
      description: Update an existing evaluator
      operationId: putApiEvaluatorsById
      parameters:
        - in: path
          name: id
          schema:
            type: string
            minLength: 1
          required: true
          description: The evaluator id.
      requestBody:
        required: false
        content:
          application/json:
            schema:
              type: object
              properties:
                name:
                  type: string
                  minLength: 1
                  maxLength: 255
                config:
                  type: object
                  propertyNames:
                    type: string
                  additionalProperties: {}
                commitMessage:
                  description: A note kept on the version this update appends.
                  type: string
                  maxLength: 500
      responses:
        '200':
          description: Success
          content:
            application/json:
              schema:
                type: object
                properties:
                  id:
                    type: string
                  projectId:
                    type: string
                  name:
                    type: string
                  slug:
                    type:
                      - string
                      - 'null'
                  type:
                    type: string
                  config:
                    anyOf:
                      - type: object
                        propertyNames:
                          type: string
                        additionalProperties: {}
                      - type: 'null'
                  workflowId:
                    type:
                      - string
                      - 'null'
                  copiedFromEvaluatorId:
                    type:
                      - string
                      - 'null'
                  createdAt:
                    type: string
                    format: date-time
                  updatedAt:
                    type: string
                    format: date-time
                  fields:
                    type: array
                    items:
                      type: object
                      properties:
                        identifier:
                          type: string
                        type:
                          type: string
                        optional:
                          type: boolean
                      required:
                        - identifier
                        - type
                      additionalProperties: false
                  outputFields:
                    type: array
                    items:
                      type: object
                      properties:
                        identifier:
                          type: string
                        type:
                          type: string
                        optional:
                          type: boolean
                      required:
                        - identifier
                        - type
                      additionalProperties: false
                  workflowName:
                    type: string
                  workflowIcon:
                    type: string
                  version:
                    anyOf:
                      - type: integer
                        exclusiveMinimum: 0
                        maximum: 9007199254740991
                      - type: 'null'
                    description: >-
                      The version this response shows: the latest, unless a
                      label or a version was asked for.
                  labels:
                    type: array
                    items:
                      type: object
                      properties:
                        label:
                          type: string
                        version:
                          type: integer
                          exclusiveMinimum: 0
                          maximum: 9007199254740991
                      required:
                        - label
                        - version
                      additionalProperties: false
                    description: >-
                      The deploy labels the evaluator carries, such as
                      production, and the version each points at.
                  createdBy:
                    anyOf:
                      - type: object
                        properties:
                          id:
                            type: string
                          name:
                            type:
                              - string
                              - 'null'
                        required:
                          - id
                          - name
                        additionalProperties: false
                      - type: 'null'
                    description: >-
                      The user who created the evaluator. Null when an API key
                      created it, or it predates creators being recorded.
                  updatedBy:
                    anyOf:
                      - type: object
                        properties:
                          id:
                            type: string
                          name:
                            type:
                              - string
                              - 'null'
                        required:
                          - id
                          - name
                        additionalProperties: false
                      - type: 'null'
                    description: >-
                      The user who changed the evaluator last. Null when an API
                      key changed it.
                  platformUrl:
                    type: string
                    format: uri
                required:
                  - id
                  - projectId
                  - name
                  - slug
                  - type
                  - config
                  - workflowId
                  - copiedFromEvaluatorId
                  - createdAt
                  - updatedAt
                  - fields
                  - outputFields
                  - version
                  - labels
                  - createdBy
                  - updatedBy
                  - platformUrl
                additionalProperties: false
        '400':
          description: Bad Request
          content:
            application/json:
              schema:
                type: object
                properties:
                  error:
                    type: string
                  message:
                    type: string
                required:
                  - error
                additionalProperties: false
        '404':
          description: Not Found
          content:
            application/json:
              schema:
                type: object
                properties:
                  error:
                    type: string
                  message:
                    type: string
                required:
                  - error
                additionalProperties: false
      security:
        - project_api_key: []
components:
  securitySchemes:
    project_api_key:
      type: apiKey
      in: header
      name: X-Auth-Token
      description: >-
        Project API key for sending traces and accessing project-scoped
        resources. Format: sk-lw-... (no underscore). Obtain one by creating a
        project via the Admin API or the LangWatch UI.

````

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