# Agent Instructions

This project uses **bd** (beads) for issue tracking. Run `bd prime` for full workflow context.

## Build & Test

```bash
cargo build --release          # Build binary
cargo test                     # Run unit tests
./target/release/nutrition-mcp # Run server (needs env vars)
```

### Smoke Test

```bash
# Start server
NUTRITION_MCP_BIND=127.0.0.1:9432 NUTRITION_MCP_API_KEY=test \
  NUTRITION_MCP_DB_PATH=/tmp/test.db ./target/release/nutrition-mcp &

# Health check
curl http://127.0.0.1:9432/health

# MCP initialize
curl -X POST http://127.0.0.1:9432/mcp \
  -H "Authorization: Bearer test" \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{"jsonrpc":"2.0","method":"initialize","params":{"protocolVersion":"2025-11-25","capabilities":{},"clientInfo":{"name":"test","version":"0.1"}},"id":1}'
```

## Architecture Overview

MCP server exposing 13 tools for personal nutrition tracking. Streamable HTTP transport with Bearer token auth.

### Module Map

```
src/
├── main.rs     — Entry point: axum server, auth middleware, /health endpoint
├── config.rs   — Config struct from env vars (bind, api_key, db_path, user_agent)
├── db.rs       — SQLite schema, migrations, DbPool type, TRACKED_NUTRIENTS const, DEFAULT_GOALS_JSON
├── api.rs      — OffClient: Search-a-licious + v3 barcode + SQLite cache (FTS5)
└── tools.rs    — NutritionServer: 13 MCP tools via #[tool_router] + ServerHandler impl
```

### SQLite Schema

- **products** — OFF cache: code (PK), product_name, brands, nutriments (JSON), serving_quantity, serving_size, image_url
- **products_fts** — FTS5 virtual table on product_name (synced via triggers)
- **entries** — Food log: id, date, meal, product_code, food_name, grams, servings, nutriments (JSON, scaled to portion)
- **daily_goal** — Single row (id=1), goals JSON with 14 nutrient targets
- **weight_log** — id, date, weight_kg

### Nutrient Storage

All nutrients stored as JSON blob in `nutriments` TEXT column (verbatim from OFF API). Daily summaries use `json_extract()` or Rust-side parsing to aggregate the 14 tracked nutrients.

### Portion Scaling

Nutrients are stored per-100g in OFF data. When logging, `scale_nutriments()` multiplies each value by `grams / 100.0`. For servings, grams = `servings * serving_quantity`.

### Meal Auto-Detection

- breakfast: before 11:00
- lunch: 11:00–15:00
- dinner: 15:00–21:00
- snack: after 21:00

## Conventions & Patterns

- **JSON nutriments** — Never hardcode nutrient columns. Store OFF nutriments verbatim as JSON, query at runtime.
- **"no data" vs 0** — Micronutrients (potassium, calcium, magnesium) are sparse in OFF. Summary shows `"no data"` when no entries have the nutrient, not 0.
- **Env vars only** — No config files. All settings via environment variables.
- **API-first** — Always check SQLite cache first, fall back to OFF API, cache results.
- **User-Agent** — Always send custom User-Agent to OFF API (good citizenship).

## Tracked Nutrients (14)

```
energy_kcal    → energy-kcal_100g
protein        → proteins_100g
carbohydrates  → carbohydrates_100g
fat            → fat_100g
fiber          → fiber_100g
sugars         → sugars_100g
saturated_fat  → saturated-fat_100g
salt           → salt_100g
fructose       → fructose_100g      (gout)
alcohol        → alcohol_100g        (gout)
potassium      → potassium_100g      (hypertension)
calcium        → calcium_100g        (hypertension)
magnesium      → magnesium_100g      (hypertension)
cholesterol    → cholesterol_100g    (hypertension)
```

## Non-Interactive Shell Commands

**ALWAYS use non-interactive flags** to avoid hanging on confirmation prompts.

```bash
cp -f source dest           # NOT: cp source dest
rm -f file                  # NOT: rm file
```

## Session Completion

1. **File issues for remaining work** - `bd create` for follow-up items
2. **Run quality gates** - `cargo build --release && cargo test`
3. **Close completed issues** - `bd close <id1> <id2> ...`
4. **PUSH** - `git add -A && git commit -m "..." && git push`
5. **Verify** - `git status` must show clean working tree