> ## Documentation Index
> Fetch the complete documentation index at: https://polyai-mintlify-665e356f.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Update voice tuning settings

> Update one or more tuning settings for a voice in the project. Only the fields you provide are changed. Set `resetToDefault` to true to revert all settings to the provider defaults. Speed is validated against the provider's allowed range.



## OpenAPI

````yaml PUT /v1/agents/{agentId}/voices/{voiceId}/tuning-settings
openapi: 3.1.0
info:
  title: PolyAI Agents API
  version: 1.0.4
  description: >-
    Build and deploy PolyAI agents programmatically. Create agents, manage
    branches, update behavior rules, configure knowledge bases, provision
    telephony, configure voices, publish deployments, and update real-time
    configs.
servers:
  - url: https://api.us.poly.ai
    description: US region
  - url: https://api.uk.poly.ai
    description: UK region
  - url: https://api.eu.poly.ai
    description: EU region
security:
  - ApiKeyAuth: []
tags:
  - name: Agents
    description: Create, list, duplicate, and delete agents.
  - name: Branches
    description: Create isolated branches for parallel development and merge back to main.
  - name: Agent Behavior
    description: >-
      Read and update an agent's behavior rules (system prompt, interaction
      style, edge cases).
  - name: Knowledge Base
    description: Manage knowledge base topics used for retrieval and tool invocation.
  - name: Variants
    description: Manage site-specific variations of an agent using attributes and variants.
  - name: Deployments
    description: Publish drafts, promote across environments, and roll back deployments.
  - name: Connectors
    description: >-
      Manage telephony connectors that bind phone numbers to voice
      infrastructure.
  - name: Phone Numbers
    description: Provision, reassign, and delete phone numbers on an agent's connectors.
  - name: Real-Time Configs
    description: Update runtime values (e.g. opening hours) outside the publish workflow.
  - name: Voices
    description: >-
      Configure agent voices: pick the active voice, run multi-voice rotations,
      tune stability and speed, and generate audio previews.
paths:
  /v1/agents/{agentId}/voices/{voiceId}/tuning-settings:
    parameters:
      - name: agentId
        in: path
        required: true
        schema:
          type: string
      - name: voiceId
        in: path
        required: true
        schema:
          type: string
        description: Voice ID from the voice library
    put:
      tags:
        - Voices
      summary: Update voice tuning settings
      description: >-
        Update one or more tuning settings for a voice in the project. Only the
        fields you provide are changed. Set `resetToDefault` to true to revert
        all settings to the provider defaults. Speed is validated against the
        provider's allowed range.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/EditVoiceTuningBody'
      responses:
        '200':
          description: Updated tuning settings
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/TuningSettingsResponse'
        '400':
          description: Validation error
        '401':
          description: Unauthorized – missing or invalid API key
        '403':
          description: Forbidden – insufficient permissions
components:
  schemas:
    EditVoiceTuningBody:
      description: >-
        Update tuning settings for a voice. Only fields you include are changed.
        Set `resetToDefault` to true to revert all settings to the provider
        defaults.
      type: object
      properties:
        stability:
          description: Voice stability (0–100)
          type: integer
          minimum: 0
          maximum: 100
        similarityBoost:
          description: Similarity boost (0–100)
          type: integer
          minimum: 0
          maximum: 100
        speed:
          description: >-
            Playback speed multiplier. The valid range depends on the voice
            provider; out-of-range values return a 400.
          type: number
          format: float
        modelId:
          description: Provider model ID override
          type: string
        resetToDefault:
          description: >-
            Reset all tuning settings to the provider defaults. Overrides other
            fields when true.
          type: boolean
      additionalProperties: false
      title: EditVoiceTuningBody
    TuningSettingsResponse:
      description: >-
        Voice tuning settings for a given voice and purpose. Fields are null
        when the tuning provider does not support them or no override has been
        set.
      type: object
      properties:
        stability:
          description: >-
            Voice stability (0–100). Higher values make the voice more
            consistent and less expressive.
          type: integer
        similarityBoost:
          description: >-
            Similarity boost (0–100). Higher values make the output sound closer
            to the original voice sample.
          type: integer
        style:
          description: Style exaggeration (provider-specific, 0–100)
          type: integer
        optimizeStreamingLatency:
          description: Streaming latency optimization level (provider-specific)
          type: integer
        speed:
          description: >-
            Playback speed multiplier. Valid range depends on the voice
            provider.
          type: number
          format: float
        modelId:
          description: Provider model ID used for synthesis
          type: string
      additionalProperties: false
      title: TuningSettingsResponse
  securitySchemes:
    ApiKeyAuth:
      type: apiKey
      in: header
      name: x-api-key

````