Stack Chan

What stack-chan/stack-chan does

The stack-chan/stack-chan MCP server brings AI-controlled interaction and emotional behavior to Stack-chan, an open-source robot built around M5Stack hardware. The project combines JavaScript-driven firmware with user applications called MODs, giving developers a way to run custom behavior on a supported device or in the browser-based simulator.

The repository is broader than the MCP functionality alone. It includes firmware, MOD examples and development scripts, browser utilities, case models for 3D printing, schematics, documentation, and release information. It fits the 📟 Embedded System category because the target runtime is a physical desktop robot rather than a purely software-based service.

How it works

A supported M5Stack device runs the Stack-chan firmware. M5StackChan CoreS3 is the standard configuration and the hardware target used for physical-release validation. The distributed firmware also supports M5Stack, M5Stack Core2, and M5Stack CoreS3. Firmware for Stack-chan RT and Takao Core2 with SG90 can be built from source, subject to the target-specific instructions.

AI-facing behavior is exposed through the project’s MCP server functionality, while the robot’s firmware handles device-side operation. MODs provide user applications and can be tested either on hardware or with the WebAssembly firmware and 3D simulator.

Setup and configuration

For a preassembled device, the documented starting point is an M5StackChan AI Desktop Robot using the CoreS3 configuration. Flashing requires a data-capable USB cable and the web firmware installer, opened in Chrome or Edge. Select “M5StackChan CoreS3” in the installer; the setup instructions state that the Moddable SDK and ESP-IDF are not required for this process.

The browser Preferences tool changes Wi-Fi and other device preferences over BLE. The MOD Gallery provides published applications, and the block editor can create or modify MODs. The simulator lets developers run MODs without immediately installing them on a physical robot.

Flashing the repository firmware replaces the factory firmware supplied by M5Stack. Restoring the factory image requires following M5Stack’s product documentation and using M5Burner.

Tools and capabilities

The stack-chan/stack-chan MCP server is intended for AI-controlled interaction with the robot and its emotional behavior. Around that server, the project supplies these documented browser capabilities:

• Install firmware over USB on a supported M5Stack device.
• Change Wi-Fi and device preferences over BLE.
• Browse, test, and install published MODs.
• Create MODs with Blockly and run them in a simulator or on hardware.
• Design custom faces by arranging eyes and a mouth.
• Simulate MODs with WebAssembly firmware and a 3D model.
• Send tracked face and hand movement over BLE through MediaPipe.

These tools are useful for prototyping behavior before deploying it to a device. The repository also includes a firmware API and development guides for contributors and MOD authors.

Limitations and notes

Hardware compatibility depends on the target. CoreS3 is the documented standard configuration, while some other targets require source builds and target-specific commands.

The project is distributed under the Apache License 2.0. Because firmware flashing overwrites the factory image, preserve the documented restoration path if returning a device to its original software is important.