Local TTS Workflow

Use this skill to debug the actual speech pipeline and to prepare text so the model reads it sanely.

Do not hardcode 127.0.0.1 blindly. Read the active OpenClaw config first and use the current messages.tts.openai.baseUrl as the source of truth.

Current known deployment in this workspace: http://127.0.0.1:8000/v1.

Current local model-path fallback worth remembering: if the server did not pull a model by registry name, it may be loading directly from a local path such as ./models/qwen3-tts-0.6b-mlx.

When exact route shape matters, the local OpenAPI document is available at:

• http://localhost:8000/openapi.json

Use this OpenAPI doc as a schema/reference source to compare this local mlx-audio server against OpenAI’s API. Do not treat it as a health check.

Core rule: normalize numbers before synthesis

If text is meant to be spoken aloud, do not leave Arabic numerals in the final TTS input.

Convert them into words first.

Examples:

• Chinese output: write 一 二 三, not 123
• English output: write one two three, not 123

This rule matters because the TTS model can go weird or read digits badly when fed raw numerals.

When preparing spoken text, normalize:

• dates
• times
• counts
• version-like strings if they will be read aloud
• mixed Chinese/English numeric snippets

If preserving exact machine-readable formatting matters, keep one copy for display and a separate normalized copy for TTS.

Workflow

1. Verify the server before touching OpenClaw

Read ~/.openclaw/openclaw.json first and extract:

• messages.tts.provider
• messages.tts.openai.baseUrl
• messages.tts.openai.model
• messages.tts.openai.voice

Check the basics against the actual configured host:

curl http://127.0.0.1:8000/health
curl http://127.0.0.1:8000/v1/models

Confirm that the intended TTS model exists.

If the model does not appear by pulled registry name, do not assume TTS is broken — this server may be loading a local-path model such as ./models/qwen3-tts-0.6b-mlx.

If the server is task-gated, ensure TTS is enabled:

MLX_AUDIO_SERVER_TASKS=tts uv run python server.py

2. Prove the raw TTS endpoint works

Always isolate the server from the client stack.

Minimal non-streaming test:

curl http://127.0.0.1:8000/v1/audio/speech \
 -X POST \
 -H 'Content-Type: application/json' \
 -d '{
 "model": "/models/lj-qwen3-tts/",
 "voice": "lj",
 "input": "你好，这是一次性返回完整音频的测试。",
 "response_format": "wav",
 "stream": false
 }' \
 --output sample.wav

Basic streaming test:

curl http://127.0.0.1:8000/v1/audio/speech \
 -H 'Content-Type: application/json' \
 -X POST \
 -d '{
 "model": "/models/lj-qwen3-tts/",
 "voice": "lj",
 "input": "你好，这是实时流式语音合成测试。",
 "response_format": "wav",
 "stream": true,
 "streaming_interval": 2.0
 }' \
 | ffplay -i -

If direct curl works but OpenClaw does not, the bug is probably in the TTS integration or provider selection layer, not the TTS backend.

3. Distinguish server failure from integration failure

Use this rule:

• Direct curl fails → fix the local TTS server first
• Direct curl works, but OpenClaw sounds wrong or falls back → inspect OpenClaw provider selection, fallback, and request shape
• OpenClaw sends requests but voice/mode is wrong → inspect fields like model, voice, instructions, ref_audio, ref_text, and streaming flags

4. Know the four TTS modes

Use the right request shape for the right model type.

Base speaker

Use built-in speaker playback.

Typical shape:

• model type: base
• no full ref_audio + ref_text
• voice.id means built-in speaker name

Base clone

Use clone-style synthesis.

Typical shape:

• model type: base
• must provide both ref_audio and ref_text, or supply a consent voice identity that resolves to both

Hard rule: do not attempt clone with only ref_audio.

CustomVoice

Use a model with prebuilt custom speakers.

Typical shape:

• model type: custom_voice
• voice may be accepted either as a plain string or as {"id":"..."} depending on the server
• for this workspace, lj-qwen3-tts / /models/lj-qwen3-tts/ must use speaker/voice lj
• do not send clone payloads

VoiceDesign

Use style-description-driven synthesis.

Typical shape:

• model type: voice_design
• must provide instructions
• do not send voice, ref_audio, or ref_text

5. Treat streaming as a real transport choice

This server supports real incremental generation, not fake post-hoc slicing.

Important behavior:

• Current OpenAPI says stream defaults to false
• response_format defaults to mp3
• streaming_interval defaults to 2.0
• Required fields are only model and input
• Extra optional fields exposed by this local server include instruct, voice, speed, gender, pitch, lang_code, ref_audio, ref_text, temperature, top_p, top_k, repetition_penalty, response_format, stream, streaming_interval, max_tokens, and verbose

Do not assume OpenAI parity on names or defaults — check the local OpenAPI schema first.

6. Use consent uploads properly

For consent-based clone flows, upload voice material through /v1/audio/voice_consents.

Use ref_text with the recording. That is not optional in spirit, even if a workflow tries to pretend otherwise.

If later synthesis depends on stored consent voices, verify that the saved identity actually maps to both:

• reference audio
• reference text

7. OpenClaw-specific debugging pattern

When OpenClaw TTS appears broken:

1. Confirm messages.tts points at the actual configured endpoint in openclaw.json
2. Confirm the intended model exists in /v1/models or is otherwise accepted by the server; if not, check whether it is a local-path-backed deployment such as ./models/qwen3-tts-0.6b-mlx
3. Confirm the selected provider is really the OpenAI-compatible path and not Microsoft fallback
4. Test direct curl with the same effective model/voice/mode assumptions
5. Inspect whether OpenClaw is falling back to another provider
6. If using [[tts:...]], verify whether single-reply override keys (model, voice, maybe provider) are enabled and are being honored
7. If needed, compare raw request shape with a dump proxy

If OpenClaw reaches the server successfully, the next question is usually which mode did it actually request.

8. Preferred test ladder

Use this order:

1. GET /health
2. GET /v1/models
3. direct non-streaming TTS test
4. direct streaming TTS test
5. consent upload test if clone is involved
6. OpenAI client compatibility test if relevant
7. OpenClaw integration test
8. dump-proxy / log inspection only if still ambiguous

9. Common conclusions

Server good, integration bad

Typical signs:

• manual curl returns playable audio
• OpenClaw output sounds like fallback voice or wrong mode
• provider selection is inconsistent

Conclusion: fix integration, not inference.

Text normalization bug

Typical signs:

• synthesis succeeds technically
• numbers are read awkwardly, skipped, or glitched

Conclusion: normalize the spoken text first. Do not blame the transport layer for a prompt-content problem.

Mode mismatch

Typical signs:

• clone request sent to CustomVoice
• VoiceDesign called without instructions
• only ref_audio present for Base clone

Conclusion: wrong request semantics for the chosen model type.

10. Use the reference doc when exact fields matter

Read references/tts-api.md when you need exact behavior for:

• /v1/audio/speech
• /v1/audio/voice_consents
• streaming vs non-streaming
• stream_format="audio" vs stream_format="event"
• mode selection and response headers
• consent storage semantics
• exact model/request mismatch errors

Do not assume generic OpenAI TTS docs fully match this local server.

Resources

references/

• references/tts-api.md — exact local API behavior, streaming semantics, mode rules, consent upload flow, and common error conditions