What is stackchan-mcp AGENTS.md?

A project guide for Stack-chan, a voice avatar running on an M5Stack CoreS3 device, with firmware and a Python server that controls it over HTTP.

Use it when changing the firmware or server, handling face assets, starting the HTTP service, or validating device-related work.

It highlights device-safety rules, protected settings, restricted tools, and important behavior such as recording data being cleared when read.

How migratorywhale/stackchan-mcp configures Codex and OpenCode

Reuse

Borrowing it

Nothing to install: this file belongs to migratorywhale/stackchan-mcp. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/migratorywhale/stackchan-mcp/master/AGENTS.md

Clone the repo

git clone --depth 1 https://github.com/migratorywhale/stackchan-mcp

Made for: Codex, OpenCode.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/migratorywhale/stackchan-mcp/agents-md/github.svg)](https://agentmods.dev/instructions/migratorywhale/stackchan-mcp/agents-md)

Your own site

<a href="https://agentmods.dev/instructions/migratorywhale/stackchan-mcp/agents-md"><img src="https://agentmods.dev/badge/instructions/migratorywhale/stackchan-mcp/agents-md/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/migratorywhale/stackchan-mcp/agents-md"><img src="https://agentmods.dev/badge/instructions/migratorywhale/stackchan-mcp/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 1,939 This file is loaded in full into every session.

When invoked 1,939 The same file — it is already loaded in full.

Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.01939	$0.01939
Opus 5.5	$0.00776	$0.00776
Sonnet 5.5	$0.00388	$0.00388
Haiku 4.5	$0.00194	$0.00194

Measured 1mo ago against content hash 3becaed0fcb6, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

stackchan-mcp AGENTS.md scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -sS --max-time 5 http://$STACKCHAN_IP/audio/status

AGENTS.md · 192 lines

How it starts

The opening of the file, as written. The whole thing — 192 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Stack-chan Project Guide

This repository contains firmware and host-side tooling for a push-based Stack-chan voice avatar running on M5Stack CoreS3.

Scope

firmware/ contains the Arduino/PlatformIO firmware for M5Stack CoreS3.
mcp-server/ contains a Python MCP server that lets clients control Stack-chan over HTTP.
faces/ and firmware/data/ contain the PNG face assets used by the device.
start-http.sh starts the MCP HTTP server. Public tunnel startup is opt-in with STACKCHAN_ENABLE_PUBLIC_MCP_TUNNEL=1.

Important Rules

Do not read or use any CLAUDE.md files. They are for a different assistant.
Do not call memory, identity, or introspection MCP tools such as imprint-memory, memory_search, breath, or similar tools.
Be careful with live-device endpoints. GET /audio consumes and clears the current recording buffer on the device.
Do not overwrite local secrets or Wi-Fi settings in firmware/src/config.h. Use firmware/config.h.example for documented defaults.
Avoid destructive git operations unless explicitly requested.
Use Conventional Commits for all commit messages.

Firmware Notes

The firmware exposes a local HTTP API on port 80:

POST /play queues a WAV URL for playback.
POST /play/pcm?session=<id>&seq=<n>&final=<0|1> plays or queues a raw 24kHz mono s16le PCM segment. The MCP server sends Fish PCM in bounded segments with Content-Length; firmware only queues segments for the active PCM session and clears queued PCM on playback timeout.
POST /mode switches between api and mcp recording behavior.
GET /audio/status reports whether a recording is ready.
GET /audio returns the latest WAV recording and then clears it.
POST /move, POST /home, POST /nod, and POST /shake control servos.
POST /face and GET /face control or inspect the current expression.
GET /snapshot returns a 320x240 JPEG from the camera.

Key services live in:

firmware/src/http_server.cpp
firmware/src/mic_service.cpp
firmware/src/playback_service.cpp
firmware/src/face_service.cpp
firmware/src/servo_service.cpp
firmware/src/camera_service.cpp
firmware/src/wifi_manager.cpp

Read the full file on GitHub · 192 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

1mo ago Changed · +7 lines · +164 tokens per session 3becaed0fcb6
2mo ago First seen · 185 lines · 1,775 tokens per session scan A e298ec230d22

Subscribe to this mod's changes

stackchan-mcp AGENTS.md is an instructions file published in the GitHub repository migratorywhale/stackchan-mcp (101 stars, last pushed 1mo ago), licensed MIT. It adds 1,939 tokens to every session, about $0.0078 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Hardware and IoT

stackchan-mcp AGENTS.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
stackchan-mcp AGENTS.mdmigratorywhale/stackchan-mcp	Instructions file	101	1mo ago	MIT	A	1,939	Codex, OpenCode
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	9,719	GitHub Copilot
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	5,516	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	yesterday	MIT	A	7,461	Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	today	MIT	A	4,680	Codex, OpenCode
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	3,093	GitHub Copilot
vscode model-prompts.instructions.mdmicrosoft/vscode	Instructions file	195k	today	MIT	A	2,022	GitHub Copilot

stackchan-mcp: Instructions file for Codex