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References

Canonical upstream links for every component mentioned in these docs. When a claim in another file cites upstream, the link is here. Treat this as the source-of-truth for re-verification.

Hardware

Resource URL What's there
M5Stack StackChan README https://github.com/m5stack/StackChan Our firmware codebase. Body spec (servos, LEDs, NFC, IR, touch, battery).
M5Stack CoreS3 datasheet https://docs.m5stack.com/en/core/CoreS3 SoC, memory, display, camera, IMU, PMU, audio codec part numbers.
meganetaaan/stack-chan (original) https://github.com/meganetaaan/stack-chan TypeScript/Moddable JS origin project — we don't run this, but it's the lineage.
78/xiaozhi-esp32 firmware (generic) https://github.com/78/xiaozhi-esp32 Multi-board voice-assistant firmware. Authority for the WS + MCP protocols below.

Voice pipeline

Resource URL What's there
xiaozhi-esp32-server https://github.com/xinnan-tech/xiaozhi-esp32-server Our Docker server. README lists all provider options.
xiaozhi-esp32-server (English README) https://github.com/xinnan-tech/xiaozhi-esp32-server/blob/main/README_en.md English feature catalog.
xiaozhi.dev docs portal https://xiaozhi.dev/en/docs/ Protocol + emotion docs.
FunAudioLLM / SenseVoiceSmall https://huggingface.co/FunAudioLLM/SenseVoiceSmall ASR model card. Languages, SER, AED, latency figures.
FunASR project https://github.com/modelscope/FunASR Toolkit that hosts SenseVoice.
Silero VAD https://github.com/snakers4/silero-vad VAD tunables, version history, limitations.
Piper TTS (engine) https://github.com/rhasspy/piper Local neural TTS.
rhasspy/piper-voices https://huggingface.co/rhasspy/piper-voices Voice catalog (includes en_GB-cori-medium). Repo license MIT; individual voices carry their own.
rany2/edge-tts https://github.com/rany2/edge-tts Unofficial EdgeTTS library — the technique we use, not the official path.

Brain

Resource URL What's there
ZeroClaw https://github.com/zeroclaw-labs/zeroclaw Agent runtime. Architecture, workspace files, providers, MCP support. Rust / dual MIT+Apache-2.0.
Qwen3-30B-A3B-Instruct-2507 https://huggingface.co/Qwen/Qwen3-30B-A3B-Instruct-2507 Model card. Param counts, experts, context length, sampling recommendations.
OpenRouter (Qwen3 page) https://openrouter.ai/qwen/qwen3-30b-a3b-instruct-2507 Pricing, latency, provider availability.
OpenRouter docs https://openrouter.ai/docs Tool calling, streaming, failover.
Qwen-Agent https://github.com/QwenLM/Qwen-Agent Tool-use framework recommended by the Qwen3 card.

Protocols

Resource URL What's there
Xiaozhi WebSocket protocol https://github.com/78/xiaozhi-esp32/blob/main/docs/websocket.md Full message catalog, hello shape, binary audio framing.
Xiaozhi MCP protocol https://github.com/78/xiaozhi-esp32/blob/main/docs/mcp-protocol.md tools/list, tools/call, AddTool vs AddUserOnlyTool.
Xiaozhi emotion docs https://xiaozhi.dev/en/docs/development/emotion/ 21-emotion catalog + wire format.
Agent Client Protocol https://agentclientprotocol.com ACP spec (Zed-originated). JSON-RPC 2.0 over stdio/HTTP/WS.
ACP prompt-turn spec https://agentclientprotocol.com/protocol/prompt-turn session/prompt, session/update, session/cancel, session/request_permission.
MCP (Model Context Protocol) https://modelcontextprotocol.io The base spec ACP reuses JSON shapes from.

Pricing (volatile)

OpenRouter pricing changes often — values below are most recently observed per references.md#brain but should be re-fetched before quoting.

Model $/M input $/M output Source
Qwen3-30B-A3B-Instruct-2507 ~$0.08 ~$0.28 OpenRouter (check live)

Licensing summary

Component License Notes
ZeroClaw MIT / Apache-2.0 (dual) Binary is yours to run.
FunASR / SenseVoiceSmall Check the HF card Weights license varies.
SileroVAD MIT
Piper engine MIT
Piper voices MIT repo, per-voice varies en_GB-cori-medium license — verify before redistributing your robot's outputs.
EdgeTTS N/A — reverse-engineered Microsoft can cut it off at any time. No support.
xiaozhi-esp32 firmware See repo Modify and redistribute per upstream.
xiaozhi-esp32-server See repo Same.
m5stack/StackChan See repo
meganetaaan/stack-chan MIT (check repo) Original project.
Qwen3 model weights See HF card Commercial-use terms vary by Qwen release.
This repo MIT See ../LICENSE.

Always verify licensing on the upstream page before redistribution — this table paraphrases and may drift.

See also

Last verified: 2026-05-17.