openclaw-cartesia — Cartesia Sonic-2 TTS for OpenClaw

OpenClaw speech provider for Cartesia Sonic-2 — high-quality text-to-speech with instant voice cloning, drop-in for OpenClaw's messages.tts pipeline, talk-voice CLI, and any channel that supports voice notes (Telegram, Slack, Discord, etc.).

Why

OpenClaw bundles ElevenLabs, Azure, Google, etc. as speech providers, but not Cartesia. Cartesia's Sonic-2 is competitively priced (generous free tier), has very low TTFB (~90ms), and produces excellent instant voice clones — but you couldn't use it as a first-class OpenClaw provider until now.

This plugin closes that gap. It registers cartesia as a speechProviders contract so OpenClaw can:

• Speak messages.tts replies in Telegram, Slack, Discord, etc. (voice notes)
• Power the talk-voice (sag) CLI skill
• Synthesize audio files (MP3) for embedded surfaces
• Stream PCM for telephony

Install

Requires Node 20+ and ffmpeg on PATH (used to transcode PCM → OGG/Opus for voice notes — Cartesia doesn't emit Opus natively).

From npm (recommended)

openclaw plugins install npm:openclaw-cartesia

From a local path (for development)

git clone https://github.com/parijatmukherjee/openclaw-cartesia.git
openclaw plugins install ./openclaw-cartesia

From git

openclaw plugins install git:github.com/parijatmukherjee/openclaw-cartesia

Configure

Drop the snippet at examples/openclaw.json.snippet into your openclaw.json (merging — don't overwrite). Minimal version:

{
  "plugins": {
    "allow": ["cartesia"],
    "entries": { "cartesia": { "enabled": true } }
  },
  "messages": {
    "tts": {
      "persona": "dobby",
      "personas": {
        "dobby": {
          "providers": {
            "cartesia": {
              "voiceId": { "source": "env", "provider": "default-env", "id": "CARTESIA_DOBBY_VOICE_ID" }
            }
          }
        }
      },
      "providers": {
        "cartesia": {
          "apiKey": { "source": "env", "provider": "default-env", "id": "CARTESIA_API_KEY" }
        }
      }
    }
  }
}

Set the env vars (recommended: 1Password CLI, sops, or systemd EnvironmentFile=):

export CARTESIA_API_KEY=sk_car_xxxxxxxxxxxxxxxx
export CARTESIA_DOBBY_VOICE_ID=00000000-0000-0000-0000-000000000000

Restart the gateway:

openclaw gateway restart

When does the voice actually fire?

This plugin only registers Cartesia as a speech provider. Whether a given assistant turn produces audio is decided by OpenClaw's top-level messages.tts.auto setting. Valid modes:

If you see Dobby reply with text and voice to every text message you send, you almost certainly want "inbound" (and a gateway restart):

openclaw config set messages.tts.auto inbound
openclaw gateway restart

suppressDuplicateText is a complement to auto, not a replacement: auto decides whether to synthesize at all, and suppressDuplicateText cancels the redundant text-send when synthesis did happen.

Provider config reference

All keys live under messages.tts.providers.cartesia (or personas.<id>.providers.cartesia for per-persona overrides):

Output formats

The plugin picks the right format based on the synthesis target:

Voice cloning

Create your clone in the Cartesia dashboard (Instant Voice Cloning is on the free tier). Copy the voice_id and set it as CARTESIA_DOBBY_VOICE_ID.

Development

git clone https://github.com/parijatmukherjee/openclaw-cartesia.git
cd openclaw-cartesia
# No build step needed — `src/` is plain ESM, `dist/` is a copy for npm publish.
# Validate:
node --check dist/index.js

To test in your local OpenClaw:

openclaw plugins install ./openclaw-cartesia
openclaw plugins inspect cartesia --runtime
openclaw gateway restart

License

MIT — see LICENSE.

Status

✅ v0.2.3 — runs in production on OpenClaw 2026.5.7. Verified end-to-end on Telegram voice notes. Telephony PCM path implemented but unverified. Issues and PRs welcome — see CHANGELOG.md for release history.

Known limitations

• suppressDuplicateText is a hook-based workaround, not a first-class OpenClaw feature. It cancels the channel's text-send by sequence proximity to the voice synthesis. Works in 1:1 chats and the canonical agent-reply path; may not handle multi-message turns or out-of-order delivery cleanly.
• Telegram channel delivers Cartesia audio as a voice note via sendVoice automatically when the synthesis is voiceCompatible: true (OGG/Opus). Other channels with voice-note support are not yet verified.

Related

• OpenClaw
• Cartesia
• OpenClaw plugin development guide
• openclaw-orchestra — multi-agent orchestration pattern for OpenClaw

Keywords

openclaw, cartesia, tts, text-to-speech, voice-cloning, speech-synthesis, sonic-2, plugin, npm, voice, telegram-bot, discord-bot, slack-bot, ai