Garmin Local MCP

Most Garmin MCP servers are built the same way: a thin live wrapper around Garmin's rate-limited, unofficial API. Every question your AI assistant asks becomes one or more live calls that return huge raw JSON blobs, a single sleep response is around 230 KB. Multi-month questions like "how does my sleep correlate with training load?" are impractical, and when Garmin changes its auth (as it did in March 2026, breaking the whole ecosystem), those servers go completely dark, even for data they already pulled yesterday.

garmin-local-mcp inverts the architecture.

What it does

• Sync once, analyze forever. Incremental sync into a local warehouse you own: immutable raw JSON snapshots plus a SQLite database.
• Server-side analysis, compact answers. Trends, correlations, personal baselines, and anomaly detection are computed locally and returned as small columnar tables, typically under 2 KB, so nothing floods the model's context.
• Offline resilience. An API breakage pauses new syncs only. Every query over already-synced history keeps working.
• A zero-auth fallback. A standalone decoder for Garmin's undocumented wellness FIT messages (sleep score, HRV, skin temperature, sleep stages, naps) ingests manually exported bundles with no login at all. No other Garmin MCP ships this.
• Curated, not sprawling. 12 composable tools, not 110.

What you can ask

Once your history is synced, Claude can answer questions like these from the local warehouse in a call or two:

• "How does my sleep score correlate with next-day resting HR?"
• "What were my anomalous HRV days this quarter?"
• "Show weekly training load vs sleep for the last three months."

Why I built it

I wanted to actually reason over my own health data, not just glance at a dashboard. That means multi-month correlations and baselines an API wrapper can't practically deliver, and it means the data has to survive Garmin breaking its own auth. Owning a local copy turns my Garmin history into something I can query like a database, for as long as I keep it.

How it works

It's a Python package (pip install garmin-local-mcp). You log in once (MFA supported; tokens persist locally), backfill your history with a resumable, rate-limit-friendly sync, and register the server with any stdio MCP client. With Claude Code:

claude mcp add --scope user garmin -- garmin-local-mcp serve

Everything lives in one directory you own (~/.garmin-mcp by default). Only two of the twelve tools write anything, and only inside that directory. MIT licensed.