signalk-mcp

# signalk-mcp An MCP server exposing a SignalK instance as a tool surface for AI agents. Part of the [Naturali](https://sailingnaturali.com) open-source boat agent stack. ## What it does Wraps a SignalK server (REST + WebSocket) and exposes the most useful marine data points as MCP tools that any compatible agent runtime (Poseidon, Claude Code, etc.) can call. ### Tools provided - `read_sensor(path)` — Read a SignalK path (e.g., `navigation.position`, `environment.wind.speedTrue`) - `get_route()` — Read the current planned route (waypoints, ETAs) - `battery_state(bank)` — Read battery state of charge, voltage, current - `depth_state()` — Water depth with under-keel clearance first (answers "how's our depth?" / "how close are we to running aground?") - `get_local_time()` — Current time localized to the vessel's GPS position - `list_paths(prefix)` — Discover which SignalK paths the vessel publishes See [SPEC.md](SPEC.md) for the response contract. ## Why a separate server? [VesselSense/signalk-mcp-server](https://github.com/VesselSense/signalk-mcp-server) already does SignalK-on-MCP well: one `execute_code` tool, the agent writes its own queries — a great fit for frontier models. `signalk-mcp` makes the opposite bet: discrete named tools with TTS-safe `display` strings, tuned for voice-first and small local models, where reliability and a speech contract matter more than query flexibility. Neither is universally better — pick the surface for the agent you actually run. Full comparison, including the failure modes: [Discrete tools vs execute_code](https://engineering.sailingnaturali.com/discrete-tools-vs-execute-code-mcp-for-voice-agents/). ## Installation ```bash uv tool install signalk-mcp ``` ## Configuration Set the SignalK base URL via environment variable: ```bash export SIGNALK_URL=http://naturalaspi.local:3000 signalk-mcp ``` ## License MIT. See LICENSE. ## Security If you find a security issue, see SECURITY.md.