otolawn-mcp

A Model Context Protocol (MCP) server for OtO Lawn smart sprinkler devices. Control your OtO zones from any MCP client (Claude, Cursor, etc.):

• List devices, zones, and schedules

• Start / stop watering on demand, with a water depth or runtime you choose

• Enable/disable zones, rename them, change their scheduled water amounts

• Browse irrigation event history (what ran, when, how much water, errors)

• Enable/disable watering schedules

• Read the weather data OtO uses for rain/wind skipping, device diagnostics, battery history and notification messages

The protocol was reverse-engineered from the OtO mobile app (v4.0.8, Android build com.oto). See docs/API.md for the full API reference. This is an independent personal-use interoperability project - it is not affiliated with or endorsed by OtO Inc. Trademarks belong to their owners.

This project talks to YOUR devices with YOUR credentials.

How it works

MCP client (Claude, etc.)
    |  (stdio JSON-RPC)
    v
otolawn-mcp server  ──► Firebase Auth (email/password sign-in)  ─► ID token
    |                  https://oto-cloud-service-ems-prod-*.run.app API
    v                  (Bearer ID-token auth)
OtO sprinkler device(s), polled by OtO's cloud

• Authentication uses the same Firebase auth endpoint the app uses, with an embedded app API key (public information, shipped inside the distributed app).

• The ID token is cached in memory and refreshed automatically (tokens last ~1 hour).

• Manual start/stop are executed via the same schedule-execution endpoints the app uses; the physical device picks up the change within ~1-2 minutes.

Related MCP server: hydrawise-mcp

Install

Requires Python 3.11+.

git clone https://github.com/DmitriyAlergant/otolawn-mcp
cd otolawn-mcp
python -m venv .venv
uv pip install -e .        # or: .venv/bin/pip install -e .

Configure credentials

export OTO_EMAIL="you@example.com"
export OTO_PASSWORD="your-oto-app-password"

These are the same email/password you use in the OtO mobile app.

Tool call contract

All tools return flat JSON blobs:

{"ok": true , "...": "payload"}
{"ok": false, "error": "description on failure"}

Water depths are millimetres (wateringQuantity at the API level). Runtimes and water depth are related by a per-zone calibration curve (timeToWater_form); water_zone accepts either.

Available tools

Example

You:    "Water the Front Lawn Far zone about 3 mm, then tell me how much it ran."
Claude: calls list_zones() ─► finds zone "Front Lawn Far"
        calls water_zone(device_id, zone_id, water_depth_mm=3)
        calls list_events(only_active=true) ...
        calls stop_watering(scheduleId) when done (or lets it finish)

Registering with Claude Code / other clients

claude mcp add otolawn -- <repo>/venv/bin/otolawn-mcp (with creds in env), or in mcp.json:

{
  "mcpServers": {
    "otolawn": {
      "command": "/path/to/otolawn-mcp/.venv/bin/otolawn-mcp",
      "env": { "OTO_EMAIL": "you@example.com", "OTO_PASSWORD": "..." }
    }
  }
}

Safety notes

• water_zone triggers real watering within a minute or so.

• A stopped water_zone run may still have briefly spawned a run - the device applies commands on its next poll, so stopping immediately after starting is also handled (event ends up USER_STOPPED).

• Rain/wind intelligence is not bypassed by manual starts; use large-enough depth if you expect the forecast to interfere.

• Deleting zones or devices cannot easily be undone.

Repo contents

• src/otolawn_mcp/client.py - OtO cloud API client (auth, zones, events, control)

• src/otolawn_mcp/server.py - MCP tool surface

• docs/API.md - the full reverse-engineered API reference

Disclaimer

This is an unofficial, independent interoperability implementation, not affiliated with OtO Inc. Endpoints may change without notice. Use at your own risk. Be mindful of local water-use rules and of what you commit to a public repo :).

MIT licensed. See LICENSE.