graph TB
    subgraph Client Layer
        A["🤖 MCP Client<br/>(Claude Code / Claude Desktop / Cursor)"]
    end

    subgraph Transport Layer
        B["📡 stdio<br/>(JSON-RPC over stdin/stdout)"]
    end

    subgraph MCP Server ["MCP Server (server.py)"]
        direction TB
        C["🔧 FastMCP Tool Router<br/>Routes tool calls to handlers"]
        D["📋 Pydantic Schemas<br/>WorkoutInput · MacrosInput · DailySummaryRequest"]
        E["⚙️ Core Business Logic<br/>insert_workout · insert_macros · fetch_daily_summary"]
        F["🗄️ Database Layer<br/>get_connection · init_db"]
    end

    subgraph Storage
        G[("💾 SQLite<br/>fitness_tracker.db")]
    end

    A <-->|"JSON-RPC"| B
    B <-->|"Tool calls & responses"| C
    C --> D
    D -->|"Validated data"| E
    E <--> F
    F <--> G

    style A fill:#4A90D9,stroke:#2C5F8A,color:#fff
    style B fill:#F5A623,stroke:#C77E1A,color:#fff
    style C fill:#7B68EE,stroke:#5A4DB2,color:#fff
    style D fill:#50C878,stroke:#3A9458,color:#fff
    style E fill:#FF6B6B,stroke:#CC5555,color:#fff
    style F fill:#DDA0DD,stroke:#AA70AA,color:#fff
    style G fill:#87CEEB,stroke:#5F9EAF,color:#000

sequenceDiagram
    participant User
    participant Client as MCP Client (Claude)
    participant Transport as stdio (JSON-RPC)
    participant Router as FastMCP Router
    participant Schema as Pydantic Validator
    participant Logic as Business Logic
    participant DB as SQLite DB

    User->>Client: "Log a 30-minute run that burned 300 calories"
    Client->>Transport: tool_call: log_workout(date, type, duration, calories)
    Transport->>Router: Deserialize JSON-RPC request
    Router->>Schema: WorkoutInput(date, type, duration, calories)

    alt Validation Fails
        Schema-->>Router: ❌ ValidationError (clear message)
        Router-->>Transport: Error response
        Transport-->>Client: Display error to user
    end

    Schema-->>Router: ✅ Validated WorkoutInput object
    Router->>Logic: insert_workout(validated_data)
    Logic->>DB: INSERT INTO workouts (date, type, duration, calories) VALUES (?, ?, ?, ?)
    DB-->>Logic: Row ID
    Logic-->>Router: {status: success, workout: {...}}
    Router-->>Transport: JSON-RPC response
    Transport-->>Client: "Logged: 30 min running — 300 kcal burned ✅"
    Client-->>User: Confirmation message

erDiagram
    WORKOUTS {
        INTEGER id PK "Auto-increment"
        TEXT date "YYYY-MM-DD (NOT NULL)"
        TEXT type "e.g. running, cycling (NOT NULL)"
        REAL duration "Minutes, > 0 (NOT NULL)"
        REAL calories "kcal burned, >= 0 (NOT NULL)"
    }

    MACROS {
        INTEGER id PK "Auto-increment"
        TEXT date "YYYY-MM-DD (NOT NULL)"
        REAL protein "Grams, >= 0 (NOT NULL)"
        REAL carbs "Grams, >= 0 (NOT NULL)"
        REAL fat "Grams, >= 0 (NOT NULL)"
    }

MCP_Project/
├── server.py              # MCP server — tools, schemas, DB helpers, entrypoint
├── test_server.py         # Pytest suite (22 tests across 6 test classes)
├── requirements.txt       # Python dependencies (fastmcp, pydantic, pytest)
├── fitness_tracker.db     # SQLite database (auto-created on first run)
├── .gitignore             # Ignores venv, __pycache__, .env
├── .env                   # Environment variables (git-ignored)
└── README.md              # This file

git clone https://github.com/MayankKapgate/fitness-tracker-mcp.git
cd MCP_Project

# Windows
python -m venv myvenv
myvenv\Scripts\activate

# macOS / Linux
python3 -m venv myvenv
source myvenv/bin/activate

pip install -r requirements.txt

pytest test_server.py -v

python server.py

claude mcp add fitness-tracker --transport stdio -- python server.py

{
  "mcpServers": {
    "fitness-tracker": {
      "command": "python",
      "args": ["C:\\Users\\Mayan\\OneDrive\\Documents\\MCP_Project\\server.py"],
      "transport": "stdio"
    }
  }
}

{
  "status": "success",
  "workout": {
    "id": 1,
    "date": "2026-08-04",
    "type": "running",
    "duration": 30.0,
    "calories": 300.0
  }
}

{
  "status": "success",
  "macros": {
    "id": 1,
    "date": "2026-08-04",
    "protein": 150.0,
    "carbs": 200.0,
    "fat": 60.0
  }
}

{
  "date": "2026-08-04",
  "workouts": {
    "count": 2,
    "entries": [
      {"id": 1, "date": "2026-08-04", "type": "running", "duration": 30.0, "calories": 300.0},
      {"id": 2, "date": "2026-08-04", "type": "weights", "duration": 45.0, "calories": 250.0}
    ],
    "total_duration_min": 75.0,
    "total_calories_burned": 550.0
  },
  "macros": {
    "count": 1,
    "entries": [
      {"id": 1, "date": "2026-08-04", "protein": 150.0, "carbs": 200.0, "fat": 60.0}
    ],
    "total_protein_g": 150.0,
    "total_carbs_g": 200.0,
    "total_fat_g": 60.0,
    "total_calories_consumed": 1940.0
  }
}

# Run all tests with verbose output
pytest test_server.py -v

# Run a specific test class
pytest test_server.py::TestWorkoutSchema -v

# Run with coverage (requires pytest-cov)
pip install pytest-cov
pytest test_server.py --cov=server --cov-report=term-missing