Text-to-speech

​

Quick start

{
  messages: {
    tts: {
      auto: "always",
      provider: "elevenlabs",
    },
  },
}

​

Supported providers

​

Configuration

{
  messages: {
    tts: {
      auto: "always",
      provider: "azure-speech",
      providers: {
        "azure-speech": {
          apiKey: "${AZURE_SPEECH_KEY}",
          region: "eastus",
          voice: "en-US-JennyNeural",
          lang: "en-US",
          outputFormat: "audio-24khz-48kbitrate-mono-mp3",
          voiceNoteOutputFormat: "ogg-24khz-16bit-mono-opus",
        },
      },
    },
  },
}

{
  messages: {
    tts: {
      auto: "always",
      provider: "elevenlabs",
      providers: {
        elevenlabs: {
          apiKey: "${ELEVENLABS_API_KEY}",
          model: "eleven_multilingual_v2",
          voiceId: "EXAVITQu4vr4xnSDxMaL",
        },
      },
    },
  },
}

{
  messages: {
    tts: {
      auto: "always",
      provider: "google",
      providers: {
        google: {
          apiKey: "${GEMINI_API_KEY}",
          model: "gemini-3.1-flash-tts-preview",
          voiceName: "Kore",
          // Optional natural-language style prompts:
          // audioProfile: "Speak in a calm, podcast-host tone.",
          // speakerName: "Alex",
        },
      },
    },
  },
}

{
  messages: {
    tts: {
      auto: "always",
      provider: "gradium",
      providers: {
        gradium: {
          apiKey: "${GRADIUM_API_KEY}",
          voiceId: "YTpq7expH9539ERJ",
        },
      },
    },
  },
}

{
  messages: {
    tts: {
      auto: "always",
      provider: "inworld",
      providers: {
        inworld: {
          apiKey: "${INWORLD_API_KEY}",
          modelId: "inworld-tts-1.5-max",
          voiceId: "Sarah",
          temperature: 0.7,
        },
      },
    },
  },
}

{
  messages: {
    tts: {
      auto: "always",
      provider: "tts-local-cli",
      providers: {
        "tts-local-cli": {
          command: "say",
          args: ["-o", "{{OutputPath}}", "{{Text}}"],
          outputFormat: "wav",
          timeoutMs: 120000,
        },
      },
    },
  },
}

{
  messages: {
    tts: {
      auto: "always",
      provider: "microsoft",
      providers: {
        microsoft: {
          enabled: true,
          voice: "en-US-MichelleNeural",
          lang: "en-US",
          outputFormat: "audio-24khz-48kbitrate-mono-mp3",
          rate: "+0%",
          pitch: "+0%",
        },
      },
    },
  },
}

{
  messages: {
    tts: {
      auto: "always",
      provider: "minimax",
      providers: {
        minimax: {
          apiKey: "${MINIMAX_API_KEY}",
          model: "speech-2.8-hd",
          voiceId: "English_expressive_narrator",
          speed: 1.0,
          vol: 1.0,
          pitch: 0,
        },
      },
    },
  },
}

{
  messages: {
    tts: {
      auto: "always",
      provider: "openai",
      summaryModel: "openai/gpt-4.1-mini",
      modelOverrides: { enabled: true },
      providers: {
        openai: {
          apiKey: "${OPENAI_API_KEY}",
          model: "gpt-4o-mini-tts",
          voice: "alloy",
        },
        elevenlabs: {
          apiKey: "${ELEVENLABS_API_KEY}",
          model: "eleven_multilingual_v2",
          voiceId: "EXAVITQu4vr4xnSDxMaL",
          voiceSettings: { stability: 0.5, similarityBoost: 0.75, style: 0.0, useSpeakerBoost: true, speed: 1.0 },
          applyTextNormalization: "auto",
          languageCode: "en",
        },
      },
    },
  },
}

{
  messages: {
    tts: {
      auto: "always",
      provider: "openrouter",
      providers: {
        openrouter: {
          apiKey: "${OPENROUTER_API_KEY}",
          model: "hexgrad/kokoro-82m",
          voice: "af_alloy",
          responseFormat: "mp3",
        },
      },
    },
  },
}

{
  messages: {
    tts: {
      auto: "always",
      provider: "volcengine",
      providers: {
        volcengine: {
          apiKey: "${VOLCENGINE_TTS_API_KEY}",
          resourceId: "seed-tts-1.0",
          voice: "en_female_anna_mars_bigtts",
        },
      },
    },
  },
}

{
  messages: {
    tts: {
      auto: "always",
      provider: "xai",
      providers: {
        xai: {
          apiKey: "${XAI_API_KEY}",
          voiceId: "eve",
          language: "en",
          responseFormat: "mp3",
        },
      },
    },
  },
}

{
  messages: {
    tts: {
      auto: "always",
      provider: "xiaomi",
      providers: {
        xiaomi: {
          apiKey: "${XIAOMI_API_KEY}",
          model: "mimo-v2.5-tts",
          voice: "mimo_default",
          format: "mp3",
        },
      },
    },
  },
}

​

Per-agent voice overrides

{
  messages: {
    tts: {
      auto: "always",
      provider: "elevenlabs",
      providers: {
        elevenlabs: { apiKey: "${ELEVENLABS_API_KEY}", model: "eleven_multilingual_v2" },
      },
    },
  },
  agents: {
    list: [
      {
        id: "reader",
        tts: {
          providers: {
            elevenlabs: { voiceId: "EXAVITQu4vr4xnSDxMaL" },
          },
        },
      },
    ],
  },
}

1. messages.tts
2. active agents.list[].tts
3. channel override, when the channel supports channels.<channel>.tts
4. account override, when the channel passes channels.<channel>.accounts.<id>.tts
5. local /tts preferences for this host
6. inline [[tts:...]] directives when model overrides are enabled

{
  messages: {
    tts: {
      provider: "openai",
      providers: {
        openai: { apiKey: "${OPENAI_API_KEY}", model: "gpt-4o-mini-tts" },
      },
    },
  },
  channels: {
    feishu: {
      accounts: {
        english: {
          tts: {
            providers: {
              openai: { voice: "shimmer" },
            },
          },
        },
      },
    },
  },
}

​

Personas

​

Minimal persona

{
  messages: {
    tts: {
      auto: "always",
      persona: "narrator",
      personas: {
        narrator: {
          label: "Narrator",
          provider: "elevenlabs",
          providers: {
            elevenlabs: { voiceId: "EXAVITQu4vr4xnSDxMaL", modelId: "eleven_multilingual_v2" },
          },
        },
      },
    },
  },
}

​

Full persona (provider-neutral prompt)

{
  messages: {
    tts: {
      auto: "always",
      persona: "alfred",
      personas: {
        alfred: {
          label: "Alfred",
          description: "Dry, warm British butler narrator.",
          provider: "google",
          fallbackPolicy: "preserve-persona",
          prompt: {
            profile: "A brilliant British butler. Dry, witty, warm, charming, emotionally expressive, never generic.",
            scene: "A quiet late-night study. Close-mic narration for a trusted operator.",
            sampleContext: "The speaker is answering a private technical request with concise confidence and dry warmth.",
            style: "Refined, understated, lightly amused.",
            accent: "British English.",
            pacing: "Measured, with short dramatic pauses.",
            constraints: ["Do not read configuration values aloud.", "Do not explain the persona."],
          },
          providers: {
            google: {
              model: "gemini-3.1-flash-tts-preview",
              voiceName: "Algieba",
              promptTemplate: "audio-profile-v1",
            },
            openai: { model: "gpt-4o-mini-tts", voice: "cedar" },
            elevenlabs: {
              voiceId: "voice_id",
              modelId: "eleven_multilingual_v2",
              seed: 42,
              voiceSettings: {
                stability: 0.65,
                similarityBoost: 0.8,
                style: 0.25,
                useSpeakerBoost: true,
                speed: 0.95,
              },
            },
          },
        },
      },
    },
  },
}

​

Persona resolution

1. /tts persona <id> local preference, if set.
2. messages.tts.persona, if set.
3. No persona.

1. Direct overrides (CLI, gateway, Talk, allowed TTS directives).
2. /tts provider <id> local preference.
3. Active persona’s provider.
4. messages.tts.provider.
5. Registry auto-select.

1. messages.tts.providers.<id>
2. messages.tts.personas.<persona>.providers.<id>
3. Trusted request overrides
4. Allowed model-emitted TTS directive overrides

​

How providers use persona prompts

​

Fallback policy

​

Model-driven directives

Here you go.

[[tts:voiceId=pMsXgVXv3BLzUgSXRplE model=eleven_v3 speed=1.1]]
[[tts:text]](laughs) Read the song once more.[[/tts:text]]

• provider (registered provider id; requires allowProvider: true)
• voice / voiceName / voice_name / google_voice / voiceId
• model / google_model
• stability, similarityBoost, style, speed, useSpeakerBoost
• vol / volume (MiniMax volume, 0–10)
• pitch (MiniMax integer pitch, −12 to 12; fractional values are truncated)
• emotion (Volcengine emotion tag)
• applyTextNormalization (auto|on|off)
• languageCode (ISO 639-1)
• seed

{ messages: { tts: { modelOverrides: { enabled: false } } } }

{ messages: { tts: { modelOverrides: { enabled: true, allowProvider: true, allowSeed: false } } } }

​

Slash commands

/tts off | on | status
/tts chat on | off | default
/tts latest
/tts provider <id>
/tts persona <id> | off
/tts limit <chars>
/tts summary off
/tts audio <text>

• /tts on writes the local TTS preference to always; /tts off writes it to off.
• /tts chat on|off|default writes a session-scoped auto-TTS override for the current chat.
• /tts persona <id> writes the local persona preference; /tts persona off clears it.
• /tts latest reads the latest assistant reply from the current session transcript and sends it as audio once. It stores only a hash of that reply on the session entry to suppress duplicate voice sends.
• /tts audio generates a one-off audio reply (does not toggle TTS on).
• limit and summary are stored in local prefs, not the main config.
• /tts status includes fallback diagnostics for the latest attempt — Fallback: <primary> -> <used>, Attempts: ..., and per-attempt detail (provider:outcome(reasonCode) latency).
• /status shows the active TTS mode plus configured provider, model, voice, and sanitized custom endpoint metadata when TTS is enabled.

​

Per-user preferences

​

Output formats (fixed)

• Voice-note capable channels: voice-note replies prefer Opus (opus_48000_64 from ElevenLabs, opus from OpenAI).
  • 48kHz / 64kbps is a good voice message tradeoff.
• Feishu / WhatsApp: when a voice-note reply is produced as MP3/WebM/WAV/M4A or another likely audio file, the channel plugin transcodes it to 48kHz Ogg/Opus with ffmpeg before sending the native voice message. WhatsApp sends the result through the Baileys audio payload with ptt: true and audio/ogg; codecs=opus. If conversion fails, Feishu receives the original file as an attachment; WhatsApp send fails rather than posting an incompatible PTT payload.
• BlueBubbles: keeps provider synthesis on the normal audio-file path; MP3 and CAF outputs are marked for iMessage voice memo delivery.
• Other channels: MP3 (mp3_44100_128 from ElevenLabs, mp3 from OpenAI).
  • 44.1kHz / 128kbps is the default balance for speech clarity.
• MiniMax: MP3 (speech-2.8-hd model, 32kHz sample rate) for normal audio attachments. For channel-advertised voice-note targets, OpenClaw transcodes the MiniMax MP3 to 48kHz Opus with ffmpeg before delivery when the channel advertises transcoding.
• Xiaomi MiMo: MP3 by default, or WAV when configured. For channel-advertised voice-note targets, OpenClaw transcodes Xiaomi output to 48kHz Opus with ffmpeg before delivery when the channel advertises transcoding.
• Local CLI: uses the configured outputFormat. Voice-note targets are converted to Ogg/Opus and telephony output is converted to raw 16 kHz mono PCM with ffmpeg.
• Google Gemini: Gemini API TTS returns raw 24kHz PCM. OpenClaw wraps it as WAV for audio attachments, transcodes it to 48kHz Opus for voice-note targets, and returns PCM directly for Talk/telephony.
• Gradium: WAV for audio attachments, Opus for voice-note targets, and ulaw_8000 at 8 kHz for telephony.
• Inworld: MP3 for normal audio attachments, native OGG_OPUS for voice-note targets, and raw PCM at 22050 Hz for Talk/telephony.
• xAI: MP3 by default; responseFormat may be mp3, wav, pcm, mulaw, or alaw. OpenClaw uses xAI’s batch REST TTS endpoint and returns a complete audio attachment; xAI’s streaming TTS WebSocket is not used by this provider path. Native Opus voice-note format is not supported by this path.
• Microsoft: uses microsoft.outputFormat (default audio-24khz-48kbitrate-mono-mp3).
  • The bundled transport accepts an outputFormat, but not all formats are available from the service.
  • Output format values follow Microsoft Speech output formats (including Ogg/WebM Opus).
  • Telegram sendVoice accepts OGG/MP3/M4A; use OpenAI/ElevenLabs if you need guaranteed Opus voice messages.
  • If the configured Microsoft output format fails, OpenClaw retries with MP3.

​

Auto-TTS behavior

• Skips TTS if the reply already contains media or a MEDIA: directive.
• Skips very short replies (under 10 chars).
• Summarizes long replies when summaries are enabled, using summaryModel (or agents.defaults.model.primary).
• Attaches the generated audio to the reply.
• In mode: "final", still sends audio-only TTS for streamed final replies after the text stream completes; the generated media goes through the same channel media normalization as normal reply attachments.

Reply -> TTS enabled?
  no  -> send text
  yes -> has media / MEDIA: / short?
          yes -> send text
          no  -> length > limit?
                   no  -> TTS -> attach audio
                   yes -> summary enabled?
                            no  -> send text
                            yes -> summarize -> TTS -> attach audio

​

Output formats by channel

• Feishu / WhatsApp transcoding: When a voice-note reply lands as MP3/WebM/WAV/M4A, the channel plugin transcodes to 48 kHz Ogg/Opus with ffmpeg. WhatsApp sends through Baileys with ptt: true and audio/ogg; codecs=opus. If conversion fails: Feishu falls back to attaching the original file; WhatsApp send fails rather than posting an incompatible PTT payload.
• MiniMax / Xiaomi MiMo: Default MP3 (32 kHz for MiniMax speech-2.8-hd); transcoded to 48 kHz Opus for voice-note targets via ffmpeg.
• Local CLI: Uses configured outputFormat. Voice-note targets are converted to Ogg/Opus and telephony output to raw 16 kHz mono PCM.
• Google Gemini: Returns raw 24 kHz PCM. OpenClaw wraps as WAV for attachments, transcodes to 48 kHz Opus for voice-note targets, returns PCM directly for Talk/telephony.
• Inworld: MP3 attachments, native OGG_OPUS voice-note, raw PCM 22050 Hz for Talk/telephony.
• xAI: MP3 by default; responseFormat may be mp3|wav|pcm|mulaw|alaw. Uses xAI’s batch REST endpoint — streaming WebSocket TTS is not used. Native Opus voice-note format is not supported.
• Microsoft: Uses microsoft.outputFormat (default audio-24khz-48kbitrate-mono-mp3). Telegram sendVoice accepts OGG/MP3/M4A; use OpenAI/ElevenLabs if you need guaranteed Opus voice messages. If the configured Microsoft format fails, OpenClaw retries with MP3.

​

Field reference

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Agent tool

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Gateway RPC

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Service links

• OpenAI text-to-speech guide
• OpenAI Audio API reference
• Azure Speech REST text-to-speech
• Azure Speech provider
• ElevenLabs Text to Speech
• ElevenLabs Authentication
• Gradium
• Inworld TTS API
• MiniMax T2A v2 API
• Volcengine TTS HTTP API
• Xiaomi MiMo speech synthesis
• node-edge-tts
• Microsoft Speech output formats
• xAI text to speech

​

Related

• Media overview
• Music generation
• Video generation
• Slash commands
• Voice call plugin