garmin-local-mcp 0.1.0

Local-first Garmin data warehouse with an analysis-grade MCP server. Sync once, analyze forever - even when the API is down.

garmin-local-mcp

Local-first Garmin data warehouse with an analysis-grade MCP server. Sync once, analyze forever, even when the API is down.

Why another Garmin MCP?

Every existing Garmin MCP server follows the same design: a thin live wrapper around Garmin's rate-limited, unofficial API. Each question your AI assistant asks becomes one or more live API calls that return huge raw JSON blobs (a single raw sleep response runs 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 fetched yesterday.

This project inverts the architecture:

• Sync once, analyze forever. Incremental sync into a local warehouse: immutable raw JSON snapshots plus a SQLite database, in a directory you own.
• Server-side analysis, compact responses. Trends, correlations, personal baselines, and anomaly detection are computed locally and returned as small columnar tables in a single tool call. Typical responses are 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 tools. 12 composable tools, not 110.

	garmin-local-mcp	Typical API-wrapper Garmin MCPs
Local data store you own	Yes (raw JSON + SQLite)	No
Works offline after an API breakage	Yes (analysis over synced history)	No
Server-side analysis (trends, correlations, baselines, anomalies)	Yes	No (raw JSON pass-through)
Response size discipline	Compact columnar tables, typically < 2 KB	Raw payloads, up to hundreds of KB
Zero-auth ingest path	Yes (FIT bundle import)	No
Tool count	12 curated	Often 20 to 110+

Quickstart

Requires Python 3.12+.

pip install garmin-local-mcp

Or run it without installing, via uv:

uvx garmin-local-mcp --help

1. Log in once (MFA supported; tokens persist locally, so future runs never ask for a password):

garmin-local-mcp login

2. Backfill your history. The sync is resumable, safe to interrupt, and throttled to be polite to Garmin's servers. A year of history is roughly 1,800 requests; for long backfills, start it and let it run (overnight works well). If it gets rate limited or interrupted, re-run the same command and it resumes where it left off.

garmin-local-mcp sync --from 2026-01-01

3. Register the MCP server with Claude Code:

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

Using a different MCP client? Any stdio-capable client works: configure it to run garmin-local-mcp serve as the server command.

4. Ask questions. Examples of what Claude can now answer from your local warehouse in one or two tool calls:

• "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 3 months."

The 12 tools

Tool	What it does
auth_status	Check whether stored Garmin Connect tokens exist (use before sync, or after an auth error).
sync	Fetch up to 60 days from Garmin Connect into the local store (default: last 30 days ending yesterday; big backfills belong in the CLI).
sync_status	Local data coverage per table, last sync time, and pending sync errors.
get_day	One merged view of a single day: wellness, sleep, HRV, training status, activities, and data-quality flags.
query_metrics	Columnar time series for one or more metrics between two dates, with daily/weekly/monthly aggregation and optional stats.
correlate	Pearson/Spearman correlation between two metrics, with day-lag support and an optional scan over lags -7..+7.
baselines	Personal mean +/- sd band per metric over a trailing window (default 28 days), to judge what is normal for this user.
anomalies	Outlier days (z-score deviations) and sustained streaks (5+ consecutive days on one side of the mean).
list_activities	Recent activities newest-first as a compact table, filterable by type, date range, and minimum distance.
get_activity	Full stored summary row for one activity (summary fields only, no GPS or sample streams).
gaps	Missing days per table plus unresolved sync errors, to find holes worth re-syncing before drawing conclusions.
import_fit	Zero-auth offline ingest of a manually exported Garmin wellness FIT bundle.

Only sync and import_fit write anything, and only inside the data directory. The server never prompts: auth problems come back as structured errors with a hint pointing at the login CLI.

Available metric names include resting_hr, sleep_score, hrv, steps, stress_avg, body_battery_high, skin_temp_dev_c, vo2max, training_load, and about 25 more; any tool given an unknown name returns the full list.

Data layout and ownership

Everything lives in one directory you own (default ~/.garmin-mcp, override with the GARMIN_MCP_DATA_DIR environment variable or --data-dir):

~/.garmin-mcp/
├── config.toml                                  # optional settings
├── tokens/                                      # Garmin Connect session tokens
├── raw/daily/YYYY/YYYY-MM-DD/<endpoint>.json    # immutable raw API snapshots
├── raw/activities/<activity_id>.json            # one snapshot per activity
└── garmin.db                                    # SQLite warehouse

The raw JSON snapshots are the source of truth and are never overwritten. The SQLite database is a derived, rebuildable index: garmin-local-mcp reparse rebuilds it from the raw snapshots entirely offline, which is the universal escape hatch for schema evolution and parser fixes. Your data never leaves your machine.

Data quality note

Garmin watches report a provisional on-device resting heart rate that can diverge sharply from Garmin Connect's finalized value on nights with sparse sampling. A real observed case: the watch reported 69 bpm on-device while Garmin Connect later finalized the same night at 56 bpm.

This project handles that in two ways:

• The API sync stores Garmin Connect's finalized value.
• The FIT importer cross-checks the provisional on-device value against the overnight heart-rate floor. A resting HR sitting more than 10 bpm above the lowest overnight sample is a rate the watch never actually observed; it gets flagged (rhr_far_above_hr_floor) and withheld, leaving the field for the API to backfill rather than storing a misleading number.

Sparse sleep-stage logging is flagged the same way (sparse_sleep_stage_logging), and flags surface in get_day so the analysis layer knows which numbers to trust.

Offline / fallback runbook

If Garmin breaks the unofficial API again (it has before):

1. Everything analytical keeps working. All query, correlation, baseline, anomaly, and gap tools run on your already-synced local history. Only new syncs pause.
2. Keep ingesting without auth. In Garmin Connect, use "Export Wellness Data" to download a daily FIT bundle, then run garmin-local-mcp import-fit <folder>. This decodes the bundle locally with zero authentication and fills the gap days. FIT-sourced rows never overwrite API-sourced rows (unless you pass --force).
3. Resume when the community catches up. Watch the python-garminconnect project for a fix, upgrade, and run garmin-local-mcp sync again. Thanks to resumable sync state, it picks up exactly where it stopped.

Configuration

Optional config.toml in the data directory:

Key	Default	Meaning
timezone	system timezone	IANA name (e.g. America/Denver) used to compute "yesterday" for sync ranges
units	metric	metric or statute
request_delay_seconds	1.0	Delay between API requests during sync
baseline_window_days	28	Default trailing window for the baselines tool

Environment variables:

Variable	Meaning
GARMIN_MCP_DATA_DIR	Override the data directory (default ~/.garmin-mcp)
GARMINTOKENS	Override the token store location (default <data_dir>/tokens)
GARMIN_EMAIL / GARMIN_PASSWORD	Optional, for non-interactive re-login; when set, garmin-local-mcp login skips the prompts (MFA may still prompt if your account requires it)

Development

python -m venv .venv
.venv/bin/pip install -e .[dev]     # Windows: .venv\Scripts\pip install -e .[dev]
pytest
ruff check .

The test suite runs fully offline against sanitized JSON fixtures and small FIT samples; CI never touches the live API.

Disclaimer

This project is not affiliated with, endorsed by, or supported by Garmin Ltd. It uses the community python-garminconnect library with your own credentials to access your own data. Garmin's APIs are unofficial and can change or break at any time; when that happens, your synced history remains fully usable and the FIT import path keeps working.

All data stays on your machine. Nothing phones home: no telemetry, no third-party services, no cloud. Treat your data directory like the personal health record it is, and never commit it to a repository.

License

MIT