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

# List deterministic signals available to evaluators

> Closed catalog of signals a deterministic evaluator can be bound to.

Drives the frontend's signal-picker UI when creating an evaluator with
``kind='deterministic'``. Sourced from the in-process probe registry —
no DB hit.



## OpenAPI

````yaml /api-reference/openapi.json get /v1/evals/signals
openapi: 3.1.0
info:
  title: Feather API
  description: >-
    Unified customer experience platform API. Manages identity, conversations,
    memory, agents, procedures, policies, model routing, knowledge bases,
    integrations, and runtime execution.
  version: 1.21.0
servers:
  - url: https://api-sandbox.featherhq.com
    description: Sandbox
  - url: http://localhost:8000
    description: Local dev
security: []
paths:
  /v1/evals/signals:
    get:
      tags:
        - evals
        - evals
      summary: List deterministic signals available to evaluators
      description: |-
        Closed catalog of signals a deterministic evaluator can be bound to.

        Drives the frontend's signal-picker UI when creating an evaluator with
        ``kind='deterministic'``. Sourced from the in-process probe registry —
        no DB hit.
      operationId: listEvalSignals
      responses:
        '200':
          description: Successful Response
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SignalCatalogResponse'
        '400':
          description: Bad request
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '401':
          description: Authentication required
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
      security:
        - APIKeyHeader: []
components:
  schemas:
    SignalCatalogResponse:
      properties:
        signals:
          items:
            $ref: '#/components/schemas/SignalCatalogItem'
          type: array
          title: Signals
      type: object
      required:
        - signals
      title: SignalCatalogResponse
      description: Closed set of deterministic signals available to evaluators.
    ErrorResponse:
      properties:
        error:
          type: string
          title: Error
        message:
          type: string
          title: Message
      type: object
      required:
        - error
        - message
      title: ErrorResponse
      description: Standard error response returned by all API error handlers.
    SignalCatalogItem:
      properties:
        key:
          type: string
          title: Key
        label:
          type: string
          title: Label
        unit:
          type: string
          title: Unit
        format:
          type: string
          enum:
            - boolean
            - enum
            - numeric
            - score
          title: Format
        aggregations:
          items:
            type: string
          type: array
          title: Aggregations
        filters:
          items:
            $ref: '#/components/schemas/SignalFilterDimResponse'
          type: array
          title: Filters
        channels:
          items:
            type: string
          type: array
          title: Channels
        description:
          type: string
          title: Description
          default: ''
      type: object
      required:
        - key
        - label
        - unit
        - format
        - aggregations
        - channels
      title: SignalCatalogItem
      description: |-
        One entry in the deterministic signal catalog.

        Drives the frontend's signal-picker UI when creating a deterministic
        evaluator. Matches the runtime ``SignalSpec`` shape minus the extractor
        callable.
    SignalFilterDimResponse:
      properties:
        key:
          type: string
          title: Key
        type:
          type: string
          enum:
            - string
            - string_list
            - string_to_string_map
          title: Type
        required:
          type: boolean
          title: Required
          default: false
        description:
          type: string
          title: Description
          default: ''
      type: object
      required:
        - key
        - type
      title: SignalFilterDimResponse
      description: One configurable filter on a deterministic signal.
  securitySchemes:
    APIKeyHeader:
      type: apiKey
      in: header
      name: x-api-key

````