Trainzilla Coach MCP

A local MCP server that lets an MCP client (Claude Desktop, Claude Code, Cursor, …) act as a Trainzilla coach. It wraps the existing GraphQL API at api.tzilla.live — no direct DB access — so all auth and business rules stay enforced by the backend.

Status: Local MVP — read tools, offline calculators, and confirm-gated write tools, plus a resource + a prompt. Not deployed anywhere. Runs entirely on your machine against your own coach login.

What it can do today (23 tools, 1 resource, 1 prompt)

Read (live data):

• whoami, list_clients, get_client_profile
• list_client_habits, get_habit_compliance, recent_habit_activity, master_habits
• list_workout_plans, list_diet_plans
• list_checkins, list_sessions, list_subscriptions, billing_summary

Calculators (offline, no network):

• calc_tdee — BMR / TDEE / recommended calories
• calc_macros — macro split by strategy (Standard 40/30/30, Pro g/kg, Keto)
• calc_1rm — 1-rep-max (Epley) + %1RM weight suggestions

Write (confirm-gated): every write tool returns a preview unless called with confirm: true, so nothing changes by accident:

• create_habit, create_master_habit, assign_master_habit
• create_checkin (with questions), schedule_session
• create_workout_plan, create_diet_plan

Still not exposed: deletes, payment execution/refunds, messaging, permission changes — by design.

Resource: tzilla://client/{clientId}/profile — a client's profile as JSON.

Prompt: weekly_client_review — pulls profile/habits/compliance/sessions and writes a read-only weekly review.

Setup

npm install
npm run build

Create .env (see .env.example) with a coach's tokens. Easiest source — log in to the coach web app, then in the browser console:

localStorage.getItem("token")        // -> TZ_ACCESS_TOKEN
localStorage.getItem("refreshToken") // -> TZ_REFRESH_TOKEN

The server auto-refreshes the access token via refreshAccessToken when it expires.

Run

Local (stdio) — for Claude Desktop etc.:

• Dev: npm run dev
• Built: npm start
• Smoke: node scripts/smoke.mjs

Remote (Streamable HTTP) — localhost only, multi-coach:

• Dev: npm run http · Built: npm run start:http
• Listens on http://127.0.0.1:8787/mcp (set MCP_HTTP_PORT / MCP_HTTP_HOST).
• Smoke: node scripts/smoke-http.mjs

Auth modes

• stdio: uses TZ_ACCESS_TOKEN (+ TZ_REFRESH_TOKEN) from env; auto-refreshes.
• Endpoint selection:
  • TZ_API_URL wins when set.
  • Otherwise TZ_ENVIRONMENT=staging uses https://qa-be2.tzilla.live/graphql.
  • All other cases default to https://api.tzilla.live/graphql.
• HTTP: pass-through — each request must send the coach's API key (Authorization: Bearer tz_... or x-api-key). The server never stores tokens; it forwards the caller's key to the GraphQL API, so the backend enforces scope (multi-coach safe). API keys are minted by the backend feature below.

Backend: trainer API keys (built in tzilla-be, local — not deployed yet)

• createApiKey(name) → returns the plaintext tz_… key once + info
• apiKeys (list, no secret) · revokeApiKey(id)
• Auth middleware accepts tz_ keys (header x-api-key or Bearer), resolves the owning coach, and stamps lastUsedAt. Only a SHA-256 hash is stored.

Use from Claude Desktop

Add to claude_desktop_config.json (Settings → Developer → Edit Config):

{
  "mcpServers": {
    "tzilla-coach": {
      "command": "node",
      "args": ["C:/New folder/tzilla-mcp/dist/index.js"],
      "env": {
        "TZ_API_URL": "https://api.tzilla.live/graphql",
        "TZ_ACCESS_TOKEN": "<paste>",
        "TZ_REFRESH_TOKEN": "<paste>"
      }
    }
  }
}

Restart Claude Desktop, then try: "Use tzilla-coach: who am I, and list my clients."

Roadmap

• Write tools (habits, check-ins, sessions, plans) — confirm-gated
• Resource (client profile) + prompt (weekly review)
• Wider read coverage (plans, check-ins, sessions, billing)
• Backend trainer API keys / PAT (built in tzilla-be, local — needs PR + deploy)
• Remote Streamable-HTTP transport (localhost, API-key pass-through auth)
• Deploy the backend API-key feature; host the HTTP server (TLS) for real remote use
• Full MCP OAuth 2.1 (replace pass-through) for a public connector
• More resources (plans / check-in history) + prompts (e.g. "draft a plan")

Layout

src/
  config.ts   # env + tiny .env loader
  client.ts   # GraphQL client: bearer auth + refresh-on-401 + role header
  calc.ts     # offline coach math (ported from HealthMath/WorkoutMath)
  index.ts    # MCP server + tool definitions (stdio)
scripts/
  smoke.mjs   # spawns the server and lists tools (handshake check)