mc3000-mcp

Safe MCP server and companion agent skill for monitoring and controlling SKYRC MC3000-compatible battery chargers over Bluetooth Low Energy.

The BLE protocol was recovered from the official Android app (MC3000 4.1.2). The production charger.* MCP tools expose safe charger operations: inspect slot state, read charger-stored voltage curves, validate battery profiles, dry-run profile writes, require explicit confirmation for live writes/starts, and provide emergency stop tools.

Status: alpha. Protocol framing, MCP stdio behavior, safety validation, and fake-client flows are tested. Live testing has confirmed MC3000 BLE operation on NiMH Charge, Discharge, Refresh, Break-in, and Cycle modes. Hardware behavior still depends on charger firmware/revision and BLE availability.

Safety warning

This software can control a physical battery charger. Wrong chemistry, current, voltage, or slot selection can damage cells or create a fire risk.

• The LLM/agent is not the safety layer; limits and dangerous-action gates are enforced in the MCP server.

• Verify battery chemistry, capacity, cell count, voltage/cutoff, temperature policy, and slot before applying any profile.

• API slot numbers are zero-based (0..3), matching Android app internals. Physical slot 1 is API slot 0.

• charger.apply_profile is dry-run by default. Live writes require confirmation_token=APPLY_PROFILE_SLOT_<slot>.

• charger.start requires a separate confirmation_token=START_SLOT_<slot>.

• Keep the charger in sight while testing. Do not expose this MCP server to untrusted clients.

• Factory/calibration reset opcodes are documented for research but intentionally not exposed as production tools.

See SECURITY.md and docs/safety-model.md before using live hardware.

Related MCP server: mihome-mcp

Features

• BLE discovery using the same advertised names as the Android app.

• Connect/disconnect over BLE FFE0/FFE1.

• Read one slot or all four slots.

• Parse slot status: chemistry, mode, status, time, voltage, current, capacity, temperature, internal resistance, LED state.

• Read firmware/hardware version and basic device settings.

• Read the app-compatible charger-stored voltage time-series (0x56) and export it as JSON/CSV.

• Validate battery profiles against conservative chemistry/device limits.

• Build/apply 40-byte MC3000 profiles with chemistry and mode-aware defaults.

• Dry-run-by-default production tools plus explicit confirmation tokens for writes/starts.

• Emergency stop for one slot or all slots.

• Companion charger-agent skill for Hermes Agent workflows.

• Legacy mc3000_* low-level tools for protocol/debug work.

MC3000 vs MC5000 selection

Model selection is based on the charger/protocol, not the inserted battery. If the physical charger is known, configure/use that model explicitly. If it is unknown, use only read-only probes: MC3000 status is opcode 0x55, while MC5000 slot status is opcode 0x91 with a slot bitmask and a different response layout. Unknown devices must not receive profile writes or start commands.

MC5000 support is being added conservatively from protocol facts in kolinger/skyrc-mc3000: status parsing can be implemented/read-only first; profile writes/start remain MC3000-only until verified on real MC5000 hardware.

Install

From source:

git clone https://github.com/nietonchique/mc3000-mcp.git
cd mc3000-mcp
python -m venv .venv
. .venv/bin/activate
python -m pip install -e '.[test]'

Once published to PyPI, install/run with one of:

pipx install mc3000-mcp
pipx run mc3000-mcp
# or
uvx mc3000-mcp

Linux BLE access requires BlueZ/DBus. Confirm the adapter is powered:

bluetoothctl show

If scans return no devices, make sure the charger is powered on, not connected to the phone app, and close enough to the PC BLE adapter.

Configure as an MCP server

Local source checkout:

hermes mcp add mc3000 --command "$(pwd)/.venv/bin/mc3000-mcp"
hermes mcp test mc3000

Published package / pipx:

hermes mcp add mc3000 --command "pipx run mc3000-mcp"
hermes mcp test mc3000

Common client config examples are in examples/claude-desktop.json, examples/codex.json, and examples/cursor.json.

Install the companion Hermes skill

The MCP server enforces safety. The skill teaches the agent the safe workflow: ask for missing battery facts, choose conservative profiles, show dry-run summaries, require explicit confirmation, monitor after start, and stop on unsafe state.

Install from this repository:

hermes skills install \
  https://raw.githubusercontent.com/nietonchique/mc3000-mcp/main/skill/SKILL.md \
  --name charger-agent

Use it explicitly:

hermes -s charger-agent
# or inside a running session:
# /skill charger-agent

The raw SKILL.md is intentionally self-contained. Additional repository files under skill/profiles/ and skill/checklists/ are examples/checklists for humans and future bundle-style registries; the server-side safety rules remain in mc3000_mcp.safety.

Production MCP tools

Preferred tools are namespaced as charger.* and enforce dry-run/confirmation on dangerous actions:

Legacy mc3000_* tools remain for low-level protocol work and backwards compatibility.

Safe workflow examples

Dry-run a bundled conservative NiMH AA profile for physical slot 4 / API slot 3:

{
  "name": "charger.apply_profile",
  "arguments": {
    "slot": 3,
    "profile_id": "nimh-aa-conservative-charge"
  }
}

Apply after explicit confirmation:

{
  "name": "charger.apply_profile",
  "arguments": {
    "slot": 3,
    "profile_id": "nimh-aa-conservative-charge",
    "dry_run": false,
    "confirmation_token": "APPLY_PROFILE_SLOT_3"
  }
}

Start after a separate explicit confirmation:

{
  "name": "charger.start",
  "arguments": {
    "slot": 3,
    "confirmation_token": "START_SLOT_3"
  }
}

Export the charger-stored voltage curve as CSV:

{
  "name": "charger.export_voltage_curve",
  "arguments": {
    "slot": 3,
    "format": "csv"
  }
}

Emergency stop all slots:

{"name": "charger.stop_all", "arguments": {}}

More examples: docs/examples.md.

Voltage curves

The Android app's graph is a voltage curve, not a generic telemetry logger. It requests opcode 0x56, receives a charger-stored sample interval plus up to 120 millivolt points, and plots/exports time vs voltage. Current, capacity, temperature, and resistance are status fields, not historical curve series.

This project exposes that same data as:

• mc3000_get_voltage_curve — low-level protocol/debug tool.

• charger.get_voltage_curve — production-safe JSON time-series.

• charger.export_voltage_curve — JSON/CSV export.

No background polling is required for the app-compatible voltage curve.

Documentation map

• SECURITY.md — hardware safety and disclosure policy.

• docs/supported-devices.md — confirmed devices and compatibility policy.

• docs/safety-model.md — what is enforced in code vs guidance.

• docs/profile-schema.md — battery profile schema and examples.

• docs/ble-protocol-notes.md — GATT/framing/opcode notes.

• docs/reverse-notes.md — detailed reverse-engineering notes.

• docs/examples.md — safe dry-run/apply/start/stop/curve examples.

• docs/publishing.md — release/listing/skill distribution checklist.

• skill/SKILL.md — companion agent playbook.

• server.json — draft Official MCP Registry metadata.

Protocol short version

• Service UUID: 0000FFE0-0000-1000-8000-00805f9b34fb

• Write/notify characteristic UUID: 0000FFE1-0000-1000-8000-00805f9b34fb

• Device names: SimpleBLEPeripheral, Charger, HitecCharger

• Normal command: 20 bytes, checksum in byte 19.

• Profile command (0x11): 40 bytes, checksum in byte 39, written as two 20-byte chunks.

• Voltage curve command (0x56): charger-stored voltage curve for a zero-based slot.

• Status/curve slot args are zero-based; start/stop use slot bitmasks.

Development

python -m pip install -e '.[test]'
python -m pytest -q
python -m ruff check .
python -m ruff format --check .
python -m mypy src tests

Local MCP stdio smoke test without hardware:

python -m mc3000_mcp.server <<'EOF'
{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05"}}
{"jsonrpc":"2.0","id":2,"method":"tools/list","params":{}}
{"jsonrpc":"2.0","id":3,"method":"tools/call","params":{"name":"charger.list_profiles","arguments":{}}}
EOF

Build/publish checks:

python -m build
python -m twine check dist/*

Repository hygiene

The repository intentionally does not include the APK, decompiled Java, local reverse-engineering scratch outputs, virtualenvs, or build caches. Those are excluded by .gitignore.

License

Apache-2.0. See LICENSE.