io.github.starlordz12/inav-mcp
MCP server for iNAV flight-controller configuration and diagnostics
Open source Open in the app JSON README (API)
About
MCP server for iNAV flight-controller configuration and diagnostics
Details
- Kind
- MCP servers
- Topic
- Maps, weather & travel
- Publisher
- starlordz12
- Origin
- official
- Category
- ferramentas
- Transport
- local
- Version
- 0.3.2
- Stars
- 2
- Last push
- 2026-08-01T01:35:47Z
- Repository state
- ativo
- Language
- Python
- License
- MIT
- Added
- 2026-08-29 04:01:27
- Updated
- 2026-08-29 04:01:27
- Origin id
io.github.starlordz12/inav-mcp
README
<!-- mcp-name: io.github.starlordz12/inav-mcp -->
# iNAV MCP Server
[](https://github.com/starlordz12/inav-mcp/actions/workflows/ci.yml)
[](LICENSE)
[](pyproject.toml)
[](https://modelcontextprotocol.io)
[](https://pypi.org/project/inav-mcp/)
An [MCP](https://modelcontextprotocol.io) server that lets Claude configure,
diagnose, and troubleshoot an **iNAV flight controller** over USB — built
**primarily for flying wings** (elevon FPV wings like the TBS Chupito and
Mojito), and also for conventional fixed-wing planes.
It talks to the FC through a single serial connection, using the iNAV **CLI**
for configuration writes and a small built-in **MSP** codec for live/binary
reads. Every write is dry-run by default, auto-backs-up first, refuses while the
board is armed, and reads back to verify.
<sub>Recorded against a live iNAV 6.1.0 flight controller over USB.</sub>
> ⚠️ **Safety:** Always remove props from the aircraft before any motor test.
> This tool never switches the FC into MSP-RX mode and never arms the aircraft.
---
## Requirements
- Python 3.10+
- An iNAV flight controller (developed against iNAV 8.x/9.x) connected over USB
- The serial port the FC enumerates as (e.g. `COM3` on Windows, `/dev/ttyACM0` on Linux)
## Install
**From PyPI** (once the first release is published):
```bash
pip install inav-mcp
```
**From source** (for development, or to run the latest unreleased code):
```bash
# from the repo root
python -m venv .venv
.venv/Scripts/python -m pip install -e . # Windows
# source .venv/bin/activate && pip install -e . # Linux/macOS
```
For development (tests):
```bash
.venv/Scripts/python -m pip install -e ".[dev]"
```
### Try it without a flight controller
You don't need any hardware to confirm the project works — the test suite runs
fully offline (no FC required):
```bash
.venv/Scripts/python -m pytest # Windows
# .venv/bin/pytest # Linux/macOS
```
All 186 tests should pass. To actually **use** the server, though, you need a
flight controller flashed with **iNAV firmware** (developed against iNAV
8.x/9.x) connected over USB — without one, the connection tools have nothing to
talk to.
## Register with Claude
Add the server to your Claude (Code or Desktop) MCP config
(`~/.claude/settings.json` or the Claude Desktop config). **Replace the paths
below with wherever you cloned this repo** — the `command` points at the Python
inside your `.venv`, and `cwd` is the repo root.
Windows:
```json
{
"mcpServers": {
"inav": {
"command": "C:\\path\\to\\inav-mcp\\.venv\\Scripts\\python.exe",
"args": ["-m", "inav_mcp.server"],
"cwd": "C:\\path\\to\\inav-mcp"
}
}
}
```
Linux / macOS:
```json
{
"mcpServers": {
"inav": {
"command": "/path/to/inav-mcp/.venv/bin/python",
"args": ["-m", "inav_mcp.server"],
"cwd": "/path/to/inav-mcp"
}
}
}
```
The server speaks MCP over **stdio**. You can also run it directly with the
installed entry point `inav-mcp`.
---
## Typical workflows
The server ships **prompts** that walk Claude through the common jobs — just pick one:
- **`new_fixed_wing_setup`** — gather hardware details → `define_aircraft` → review → apply.
- **`troubleshoot_no_arm`** — decode arming-prevention flags → guided fixes.
- **`configure_modes`** — identify switches from live RC → suggest a layout → assign modes.
Or drive it conversationally, e.g.:
> "Connect to my FC on COM3 and tell me why it won't arm."
> "Set up a 4S flying wing on DSHOT600, then show me the commands before applying."
---
## Tools (35)
### Connection & identity
| Tool | What it does |
|---|---|
| `list_serial_ports()` | List available serial ports. |
| `find_fc(baud=115200, probe_all=False)` | Auto-detect which port has an FC by probing for MSP identity — no guessing the port. |
| `connect(port, baud=115200)` | Open the FC connection, return board identity. |
| `disconnect()` | Close the connection. |
| `board_info()` | FC variant, firmware version, target, API version, sensors. |
### Hardware setup
| Tool | What it does |
|---|---|
| `define_aircraft(name, wing_type, esc_protocol, cells, …)` | Offline planner — stores a profile and generates the CLI config plan. |
| `get_aircraft_profile()` | The current declared profile + plan. |
| `apply_aircraft_setup(confirm=False)` | Apply the plan (gated: not armed, auto-backup, read-back verify). On iNAV, applying is inherently save+reboot. |
| `check_config()` | `diff all` + lint against the declared profile + ARM check. |
### Flight modes & switches
| Tool | What it does |
|---|---|
| `suggest_mode_layout(skill_level, num_switches, has_gps=False)` | Recommend a fixed-wing switch/mode layout (offline). |
| `set_flight_mode(mode_name, aux_channel, range_low, range_high, confirm=False)` | Assign one mode to an aux range. |
| `assign_switch(switch_channel, switch_positions, mode_per_position, confirm=False)` | Map a whole 2/3/6-pos switch in one call. |
| `clear_flight_mode(mode_name, confirm=False)` | Remove a mode's switch assignments. |
### Diagnostics
| Tool | What it does |
|---|---|
| `diagnose()` | Full sweep: arming, sensors, RC, battery, GPS → prioritized fixes. |
| `why_wont_it_arm()` | Decode arming-prevention flags into plain reasons + fixes. |
| `read_rc_channels()` | Live RC channel values — flip a switch, see which channel moves. |
| `read_sensors()` | Live attitude, per-sensor health, battery. |
| `get_status()` | MSP status + CLI `status`/`tasks`. |
| `list_flight_modes()` | All modes and their current switch assignments. |
| `check_failsafe()` | Read `failsafe_*` settings, explain the RC-loss procedure, flag risky setups (e.g. RTH without GPS). |
### Bench tests & calibration
| Tool | What it does |
|---|---|
| `test_motor(motor, throttle_us=1100, duration_s=2.0, props_removed=False, confirm=False)` | Spin ONE motor briefly. Hard-gated: `props_removed=True` + `confirm=True`, refuses while armed, always auto-stops. (No `test_servo` — iNAV has no live servo override; verify surfaces with the TX sticks + `read_rc_channels()`.) |
| `calibrate_accelerometer(confirm=False)` | Zero-level the accelerometer (board flat + still). Fixes most "not level" arming blocks. |
| `calibrate_magnetometer(confirm=False)` | Calibrate the compass (rotate the craft ~30s). |
### Navigation & tuning
| Tool | What it does |
|---|---|
| `read_gps()` | Live GPS fix/sats/position + nav-readiness assessment (read-only). |
| `configure_gps(provider="UBLOX", sbas=None, confirm=False)` | Enable the GPS feature and set provider/SBAS. |
| `set_nav(rth_altitude_m=None, rth_climb_first=None, rth_allow_landing=None, loiter_radius_m=None, confirm=False)` | Set fixed-wing RTH altitude / climb-first / landing / loiter radius. |
| `read_tuning()` | Read fixed-wing PID gains, rates, and filter cutoffs. |
| `set_pid(axis, p=None, i=None, d=None, ff=None, confirm=False)` | Set fixed-wing P/I/D/FF gains for one axis. |
### Config management
| Tool | What it does |
|---|---|
| `backup_config(label=None)` | Save `diff all` to a timestamped file under `./backups/`. |
| `list_backups()` | List saved backups (path, time, size, label), newest first. |
| `restore_config(path, confirm=False)` | Replay a saved backup via CLI. |
| `set_failsafe(procedure=None, throttle_us=None, confirm=False)` | Set the RC-loss procedure / throttle (atomic write; FC validates the procedure token). |
| `cli(command, confirm_for_writes=False, props_removed=False)` | Raw CLI escape hatch (ONE command, one reboot). Writes need `confirm_for_writes`; a live `motor` test needs `props_removed=True` and is never saved. |
| `cli_batch(commands, confirm_for_writes=False)` | Run MANY CLI commands in **one** session → **one** reboot. Read-only batch exits without saving; a write batch backs up + saves once (rolls back if any command is rejected). Motor/`save`/`exit` commands refused. |
| `save_and_reboot(confirm=False)` | `save` to EEPROM and reboot (marks the connection stale). |
## Resources
- `inav://modes-reference` — iNAV mode glossary with fixed-wing relevance.
- `inav://current-profile` — the declared aircraft profile + generated plan.
- `inav://last-backup` — the most recent `diff all` backup.
---
## Safety model
1. **Props-off gate** — `test_motor()` and any live `motor` command via `cli(...)` require `props_removed=True` (the generic write-confirm cannot bypass it), refuse while the board is armed, and are never saved. `test_motor()` also clamps throttle/duration and always commands the motor back to stop.
2. **Armed guard** — all writes (and motor tests / calibrations) refuse if the FC reports armed.
3. **Auto-backup** before every write; the backup path is returned.
4. **Dry-run by default** — writes return the exact commands; `confirm=True` applies.
5. **Read-back verify** — after applying, settings are re-read and mismatches flagged.
6. **`save` = reboot** — `save_and_reboot` warns and marks the connection stale.
7. **No receiver-mode changes** — the FC is never switched to MSP-RX.
## Reboot model — why batching matters
On iNAV, **leaving the CLI always reboots the FC** — both `save` (persist to
EEPROM) and `exit` (discard changes) trigger a reboot, after which the USB VCP
re-enumerates and we reconnect (~6–8 s, surfaced as `reboot_seconds`). So **every
CLI round-trip costs one reboot**, including read-only ones (`get`, `diff`,
`dump`, `version`). There is no way to read over the CLI without that reboot —
the only lever is to do fewer CLI sessions.
What this server does to keep reboot churn down:
- **Reads prefer MSP, which never reboots.** `get_status`, `read_rc_channels`,
`read_sensors`, `read_gps`, `list_flight_modes`, `why_wont_it_arm`, `diagnose`,
and the armed-guard all read structured data over MSP — zero reboots. Only data
that's CLI-only (`diff all`, `get failsafe`, PID/rate/filter `get`s) pays a reboot.
- **Writes are atomic and batch internally.** Each write tool
(`apply_aircraft_setup`, `set_flight_mode`, `assign_switch`, `set_pid`,
`set_failsafe`, `restore_config`, …) opens **one** CLI session: backup → apply
all commands → save → reboot once. Multiple settings = one reboot.
- **`cli_batch()` for ad-hoc runs.** Instead of calling `cli()` in a loop (one
reboot **per** command — the cadence that can knock a board into DFU), pass a
list to `cli_batch()`: one session, one reboot. Read-only batches `exit` without
saving; write batches back up and `save` once (rolling back if any command is
rejected).
- **Resilient reconnect.** After a reboot the reconnect waits a short settle, then
polls with backoff; if the original COM port doesn't return it scans for a
re-enumerated one, and if the board came back in **DFU/bootloader mode** it says
so and tells you to power-cycle (USB unplug/replug) rather than hanging.
## How it works
- **Single serial handle** shared between MSP and CLI modes (`connection.py`),
tracked by a `mode` state machine. Never two handles on one port.
- **CLI-first writes** — the CLI is stable across firmware versions; MSP command
IDs can drift. A thin MSP v1/v2 codec (`msp.py`) handles only the live binary
reads (status, RC, attitude, analog, GPS, sensor health, mode ranges, box maps).
- **Box IDs are resolved at runtime** via `MSP_BOXNAMES` + `MSP_BOXIDS` — never hardcoded.
- **Arming flags** are decoded from `knowledge/arming_flags.json`, calibrated to
iNAV 8.x/9.x bit positions. The table declares its calibrated major versions, and
`connect()` / `board_info()` / `why_wont_it_arm()` / `diagnose()` **warn when the
connected firmware is outside that range** (bit positions shift between majors, so
flag *names* may be mislabelled even though the raw flag value is correct).
## Development
```bash
.venv/Scripts/python -m pytest # 186 tests, all offline (no FC needed)
```
The suite covers the MSP codec round-trips, CLI response parsing, the diagnostic
rule engine, offline profile/command generation, mode-range read-modify-write
logic (against a mock connection), and resource/prompt registration.
Project layout:
```
inav_mcp/
server.py # FastMCP app: all tools, resources, prompts
connection.py # single serial handle, MSP + CLI mode switching
msp.py # MSP v1/v2 codec + parsers
cli.py # CLI response parsing, write-command detection
modes.py # box maps, mode-range read/write, layout planner
profiles.py # AircraftProfile + offline CLI command generator
troubleshoot.py # diagnose() rule engine + arming-flag decode
safety.py # armed guard, backup paths
state.py # connection + profile singletons
knowledge/ # arming_flags / modes_reference / esc_protocols / fc_targets (JSON)
tests/ # offline pytest suite
tools/ # gen_readme_tools.py — regenerates the tool reference below
examples/ # flying_wing_quickstart.md — end-to-end walkthrough
```
Release history is in [CHANGELOG.md](CHANGELOG.md).
## Full tool reference
Complete, signature-accurate list — regenerate after changing tools with
`python -m tools.gen_readme_tools` (a test fails if this drifts):
<!-- TOOLS:AUTOGEN:START -->
_35 tools — auto-generated by `tools/gen_readme_tools.py`; do not edit by hand._
| Tool | Description |
|---|---|
| `apply_aircraft_setup(confirm=False)` | Apply the declared aircraft profile to the FC, then save and reboot. |
| `assign_switch(switch_channel, switch_positions, mode_per_position, confirm=False)` | Map a multi-position switch's detents to flight modes in one call. |
| `backup_config(label=None)` | Save the current FC config to a timestamped backup file. |
| `board_info()` | Read flight-controller identity over MSP. |
| `calibrate_accelerometer(confirm=False)` | Calibrate the accelerometer (zero-level). Fixes most 'not level' / 'accel not |
| `calibrate_magnetometer(confirm=False)` | Calibrate the compass (magnetometer). Only useful if a compass is installed. |
| `check_config()` | Compare the FC's actual configuration against the declared aircraft profile. |
| `check_failsafe()` | Read and explain the failsafe configuration (what happens on RC loss). |
| `clear_flight_mode(mode_name, confirm=False)` | Remove all switch assignments for a flight mode (disables its slots via CLI 'aux'). |
| `cli(command, confirm_for_writes=False, props_removed=False)` | Raw CLI escape hatch — run any iNAV CLI command directly. |
| `cli_batch(commands, confirm_for_writes=False)` | Run MANY CLI commands in ONE CLI session — a single reboot for the whole batch. |
| `configure_gps(provider='UBLOX', sbas=None, confirm=False)` | Enable the GPS feature and set the receiver provider / SBAS (atomic CLI write). |
| `connect(port, baud=115200)` | Open the serial connection to the FC and return board identity. |
| `define_aircraft(name, wing_type, esc_protocol, cells, fc_target=None, motor_kv=None, motor_poles=14, servo_count=None, notes=None)` | Define the aircraft hardware profile and generate a configuration plan. |
| `diagnose()` | Full diagnostic sweep — the flagship troubleshooter. |
| `disconnect()` | Close the serial connection to the FC. |
| `find_fc(baud=115200, probe_all=False)` | Auto-detect which serial port has a flight controller, so you don't guess. |
| `get_aircraft_profile()` | Return the currently declared aircraft profile. |
| `get_status()` | Read FC status via both MSP and CLI. |
| `list_backups()` | List saved config backups under ./backups/, newest first. No FC needed. |
| `list_flight_modes()` | List all available flight modes and their current switch assignments. |
| `list_serial_ports()` | List all available serial ports. |
| `read_gps()` | Live GPS status: fix type, satellites, position, speed, HDOP + nav-readiness. |
| `read_rc_channels()` | Read live RC channel values via MSP. |
| `read_sensors()` | Read live sensor values: attitude, per-sensor health, and analog (battery). |
| `read_tuning()` | Read fixed-wing PID gains, rates, and key filter cutoffs (via CLI). |
| `restore_config(path, confirm=False)` | Restore FC config by replaying a backup file's CLI commands, then save+reboot. |
| `save_and_reboot(confirm=False)` | Save the running config to EEPROM and reboot the FC. |
| `set_failsafe(procedure=None, throttle_us=None, delay_s=None, off_delay_s=None, confirm=False)` | Set the core failsafe behaviour (atomic CLI write: backup → apply → save+reboot). |
| `set_flight_mode(mode_name, aux_channel, range_low, range_high, confirm=False)` | Assign a flight mode to an aux channel range (read-modify-write via CLI 'aux'). |
| `set_nav(rth_altitude_m=None, rth_climb_first=None, rth_allow_landing=None, loiter_radius_m=None, confirm=False)` | Set core fixed-wing navigation / RTH parameters (atomic CLI write). |
| `set_pid(axis, p=None, i=None, d=None, ff=None, confirm=False)` | Set fixed-wing PID gains for ONE axis (atomic CLI write). |
| `suggest_mode_layout(skill_level='beginner', num_switches=2, has_gps=False)` | Recommend a fixed-wing flight-mode/switch layout. Pure knowledge — no FC needed. |
| `test_motor(motor, throttle_us=1100, duration_s=2.0, props_removed=False, confirm=False)` | Spin ONE motor briefly for a bench test (direction / wiring / response). |
| `why_wont_it_arm()` | Decode the FC's arming-prevention flags into plain English. |
<!-- TOOLS:AUTOGEN:END -->
## License
MIT. This project ships its own MSP codec and does **not** import GPL libraries
(uNAVlib / YAMSPy) at runtime, keeping it permissively licensed.