# Wellness CGM MCP

Local-first continuous glucose monitor MCP for AI agents. Two real backends: Dexcom (official Developer API, sandbox + production) and FreeStyle Libre — the OTC sensor (Libre 2 / Libre 3) — via LibreLink Up. Pick the backend with CGM_PROVIDER (dexcom | libre); it auto-detects libre when only LIBRELINKUP_* creds are set. Both feed the same ADA TIR / GMI / hypo / meal-response engine. Mock-data mode lets agents demo every tool without any credentials.

Repository: https://github.com/davidmosiah/wellness-cgm-mcp
NPM: https://www.npmjs.com/package/wellness-cgm-mcp
Docs: https://wellness.delx.ai/connectors/cgm
Primary command: npx -y wellness-cgm-mcp doctor
MCP command: wellness-cgm-mcp

Core tools:
- cgm_agent_manifest — runtime contract, supported clients, env vars
- cgm_capabilities — providers (dexcom + libre), metrics, privacy modes
- cgm_connection_status — active provider, credentials, mode (live vs mock)
- cgm_privacy_audit — what is stored locally vs sent to the CGM provider
- cgm_data_inventory — metric catalog, TIR ranges, GMI formula reference
- cgm_glucose_now — most recent reading + trend (Dexcom or Libre)
- cgm_glucose_window — all readings over last N hours (default 24)
- cgm_daily_summary — mean/median/min/max/stdev + GMI + CV + 2 TIR profiles
- cgm_meal_response — baseline → peak → return-to-baseline + band (excellent/good/moderate/poor)
- cgm_hypo_events — hypoglycemia event detection (ADA Level 1 < 70, Level 2 < 54)
- cgm_authorize_url — Dexcom OAuth authorize URL builder
- cgm_libre_status — FreeStyle Libre (LibreLink Up) region + config + mock/live
- cgm_libre_login — log in to LibreLink Up + list followed sensors (token never returned)
(plus profile/onboarding/quickstart/demo helpers — see cgm_agent_manifest for the full list)

Optional env vars:
- CGM_PROVIDER — dexcom (default) or libre; auto-detects libre when only LIBRELINKUP_* creds are set
- DEXCOM_ENV — sandbox (default) or production
- DEXCOM_CLIENT_ID, DEXCOM_CLIENT_SECRET — from developer.dexcom.com
- DEXCOM_REDIRECT_URI — must match exactly what you registered
- DEXCOM_ACCESS_TOKEN — set after running `wellness-cgm exchange <auth_code>`; without it, mock mode is used
- DEXCOM_REFRESH_TOKEN — used to refresh access tokens (refresh logic lands later)
- LIBRELINKUP_EMAIL, LIBRELINKUP_PASSWORD — FreeStyle Libre via LibreLink Up (same login as the LibreLinkUp app)
- LIBRELINKUP_REGION — eu (default) | us | de | fr | au | jp ...; login also auto-follows a regional redirect
- LIBRELINKUP_PATIENT_ID — pin a specific sensor if you follow more than one
- WELLNESS_CGM_LOCAL_DIR — defaults to ~/.wellness-cgm
- WELLNESS_CGM_QUIET=1 — suppress the stderr community CTA

Workflow for agents:
1. Call cgm_connection_status — check the active provider (dexcom | libre) and whether mode=live or mode=mock. For Libre, run cgm_libre_login first to verify creds + discover the patientId.
2. cgm_glucose_now for spot checks; cgm_daily_summary for trends.
3. cgm_meal_response with the meal_time from wellness-nourish to compute spike + band.
4. Surface BOTH TIR profiles (diabetic 70-180 ADA + metabolic-health 70-140 Levels-style).
5. NEVER recommend insulin/medication adjustments; defer to clinician.

Time-in-range:
- Diabetic profile: 70-180 mg/dL (ADA standard).
- Metabolic-health profile: 70-140 mg/dL (Levels-style, for non-DM users).

Meal response bands (peak delta from baseline):
- excellent: < 30 mg/dL
- good: 30-49
- moderate: 50-79
- poor: ≥ 80

Safety:
- CGM data is medical-record sensitive — treat accordingly.
- Mock mode clearly tagged via mock=true on every payload.
- Never claim diagnostic accuracy; readings are observed values.
- For T1/T2 diabetics, defer dosing decisions to clinician.
- Not affiliated with Dexcom or Abbott (FreeStyle Libre).