Pocket Master MCP Server

pocket-master-mcp

An MCP server that lets an AI assistant (Claude Desktop or any other MCP client) control a Sonicake Pocket Master guitar processor over USB MIDI. It also includes offline tools that translate the device's UI into other languages, with Russian built in.

Describe the sound you want in plain words ("tight modern metal rhythm", "clean with a wide chorus, less reverb"). The assistant picks models, sets parameters, reorders the chain, and saves and names presets on the unit.

Unofficial project. It is not affiliated with or endorsed by Sonicake. The protocol is based on the reverse-engineering work in PocketEdit. Reading (current preset, preset names, the full edit buffer) is verified on a real unit with firmware V1.3.3. Writing presets has seen little hardware testing so far, so run backup_presets first. Patched firmware is unofficial too: you use it at your own risk.

What it can do

• Live editing: select a model in any block (22 amps + 5 captured-amp profiles, 20 cabs/IRs, 8 drives, FX1/FX2 with 15–17 effects each, 9 delays, 10 reverbs, 3 EQs, noise gate), switch blocks on and off, and set parameters by name with range checking (Gain, Time in ms, Rate in Hz, Mode = Bass, +3dB = on, …).
• Signal chain: reorder NR / FX1 / FX2 / DLY / RVB around the fixed DRV-AMP-IR-EQ block.
• Read state: decode the edit buffer (models, on/off, parameter values, chain, preset volume) and list the 100 preset names.
• Presets: select presets, save the edit buffer to a user slot P01–P50 with a name, rename presets, back up and restore presets.
• Tone files: apply a whole tone from a JSON file. Examples are in examples/presets.
• Globals: global volume, input / FX rec / monitor / BT rec levels.
• UI language: build a firmware file with a translated UI (Russian built in, see UI language).

Requirements

• A Sonicake Pocket Master connected over USB. It shows up as a class-compliant MIDI port.
• Python 3.10+.
• An MCP client, for example Claude Desktop.

The server has to run on the computer the Pocket Master is plugged into, because it needs direct access to the USB MIDI port.

Installation

The easiest way is uv: uvx downloads and runs the server.

Claude Desktop

Open Settings → Developer → Edit Config and add:

{
  "mcpServers": {
    "pocket-master": {
      "command": "uvx",
      "args": ["pocket-master-mcp"]
    }
  }
}

Restart Claude Desktop completely. If Claude cannot find uvx, use its absolute path (which uvx, typically ~/.local/bin/uvx). For firmware previews (PNG), use "args": ["--from", "pocket-master-mcp[preview]", "pocket-master-mcp"].

Alternatively, run pipx install pocket-master-mcp or pip install "pocket-master-mcp[preview]" and use "command": "pocket-master-mcp".

From source

git clone https://github.com/voronkovd/pocket-master-mcp.git
cd pocket-master-mcp
python3 -m venv .venv
.venv/bin/pip install -e ".[dev]"

Then use "command": "/absolute/path/to/pocket-master-mcp/.venv/bin/pocket-master-mcp".

Configuration

Checking the connection

1. From a source checkout, run python scripts/midi_check.py. It is read-only: it prints the ports, the current preset and the preset names.
2. In Claude: "connect to the Pocket Master and show the device state". Compare the models and values with the screen of the unit.
3. If something is decoded wrongly, set PM_DEBUG_TOOLS=1 and ask for debug_raw_dump. It writes the raw dump with offsets to ~/.pocket-master-mcp/logs/. Please attach it to an issue.

Tools

Blocks are nr (gate), fx1, drv, amp, ir, eq, fx2, dly, rvb. Aliases such as gate, drive, cab, delay and reverb also work. Captured-amp profiles (User Profile 1..5) are selected in the amp block, and the server switches the amp mode automatically.

UI language (firmware)

The firmware has two UI languages, English and Chinese. build_language_firmware replaces the Chinese one with a language pack: Russian (ru) is built in, and your own packs can be saved with save_language_pack. It works offline on a copy of the official firmware file, never on the device. Flash the result with the official Sonicake Manager, then choose the language in the device's settings. To go back, flash the official file.

• A pack maps English UI strings to translations. Strings that are not listed stay English. Effect and parameter names exist only in English in the firmware and are not translated.
• The device font is a tiny pixel font, so glyphs are hand-drawn in data/glyphs.json. Cyrillic is included. For other scripts, add glyphs there first; the build stops and lists any character without a glyph.
• The build checks the result: CRCs, every string, a glyph for every character, and that only the UI section changed. It refuses already-patched input, and it never overwrites the source.
• This is unofficial, so use it at your own risk. It was tested on V1.3.3 and builds for V1.1.0. Details are in docs/FIRMWARE.md.

Example: "Build a Russian firmware from ~/Downloads/Pocket Master Firmware V1.3.3.bin, but use 'Сохр.' for Save."

The same is available without an MCP client:

pocket-master-fw info  "Pocket Master Firmware V1.3.3.bin"
pocket-master-fw build "Pocket Master Firmware V1.3.3.bin" -l ru --set "Save=Сохр."

Firmware files are not part of this project. Download them from Sonicake.

Tone format

{
  "chain": ["nr", "fx1", "drv", "amp", "ir", "eq", "fx2", "dly", "rvb"],
  "blocks": {
    "drv": {"model": "Scream", "params": {"Gain": 5, "Tone": 60, "Vol": 85}},
    "amp": {"model": "Sol 100 LD", "params": {"Gain": 62, "Middle": 58}},
    "ir":  {"model": "BritGN 4x12"},
    "dly": {"on": false},
    "rvb": {"model": "Room", "params": {"Mix": 10}}
  },
  "preset_volume": 70
}

Selecting a model resets its parameters to the model defaults, so parameters are applied after the model (apply_preset does this in the right order).

Limitations

• Only the edit buffer can be dumped. Backups therefore load every preset one by one, and unsaved edits are lost.
• Backups store decoded settings, not raw preset bytes, so anything the decoder does not know (if anything) is not restored.
• Global settings can be written but not read yet.
• User IR / captured-amp contents cannot be uploaded, only selected.

How it works

• docs/PROTOCOL.md: MIDI SysEx framing (nibble expansion, CRC-8), commands, the edit-buffer dump and the preset names.
• docs/FIRMWARE.md: the HTFW firmware container, the update protocol of Sonicake Manager, and the LVGL UI fonts and string tables.
• tools/build_device_map.py regenerates the model and parameter table from a PocketEdit checkout.

Development

.venv/bin/pip install -e ".[dev]"
.venv/bin/pytest

The tests rebuild a sample of the device commands captured by PocketEdit and real replies from a unit, and they run the device logic against a fake Pocket Master, so no hardware is needed. Firmware build tests run when an official firmware file is in local/ or PM_TEST_FIRMWARE points to one.

Credits and license

• PocketEdit by suckyble and contributors (hnikolov and others) is the source of the protocol knowledge. The model and parameter table (data/device_map.json, regenerated by tools/build_device_map.py) and the command samples in tests/fixtures/pocketedit_commands.json are derived from its libraries. PocketEdit does not state a license. If you are its author and want these files changed or removed, please open an issue.
• The firmware language tools contain no Sonicake code or data. They patch a firmware file the user supplies.

This code is MIT licensed, see LICENSE. Sonicake and Pocket Master are trademarks of their owners. Model names refer to the products they emulate and are used only to identify the models.