# diet_guard

A log-to-unlock gate: locks the desktop until a meal is logged once a meal
slot (08:00 / 12:00 / 16:00 / 20:00) has elapsed without one, and tracks a
sealed daily calorie/macro budget.

## Install

```bash
bash install.sh
```

This installs the package + dependencies into system Python's user
site-packages (the systemd service runs `/usr/bin/python` directly, not a
venv — see `CLAUDE.md`), installs the systemd user timer, seals your daily
budget, and locks the budget file immutable.

## Usage

```bash
python -m diet_guard init          # one-time: compute and seal today's budget
python -m diet_guard gate --demo   # test the lock window (safe, closeable)
python -m diet_guard averages      # weekly/monthly average kcal vs budget
```

### Averages

`averages` prints the mean kcal/day for this week, last week, this month and
last month, each labelled **under** / **slightly over** / **very over**.

Three rules make the number honest, and all three are mirrored in the phone
app and the gate's History tab:

* the mean is over **logged days only** -- a day you forgot to log is not a
  zero-calorie day, and averaging it in as one would make every gap in the log
  read as "well under budget";
* the yardstick is the **mean of the budgets that applied on those same days**,
  not today's budget, so editing the budget never retroactively reclassifies a
  past week (same reason the calendar uses `.budget_history`);
* **today is excluded** -- every period ends at yesterday, because a
  half-logged today drags the mean far enough to flip the band. On a Monday
  "this week" therefore reports no logged days yet rather than a flattering
  number.

The band boundaries are the calendar's own (at or under budget / up to 20%
over / more than 20% over), so a period and its day cells can never disagree
about what "over" means.

The timer runs the gate automatically every ~15 minutes; no manual
invocation is needed once installed.

## MCP server

An optional [Model Context Protocol](https://modelcontextprotocol.io) server
lets an MCP client (Claude Code and its subagents) query today's intake and log
meals as typed tools instead of shelling out to the CLI. It runs in its own
venv (`~/.venvs/diet-guard-mcp`) so the `mcp` SDK never touches the
dependency-light system/CLI python path.

Tools:

- `get_status` — today's consumed kcal + macros, the consumption *band*
  (`on track` / `approaching limit` / `OVER BUDGET`, or none when no budget is
  sealed), plus due / logged / current meal slots.
- `list_today` — today's logged meals (description, kcal, macros, source, slot).
- `get_slots` — the day's fixed meal slots and the current one.
- `get_averages` — average kcal/day for this/last week and this/last month,
  each with its band (`under` / `slightly_over` / `very_over`). Returns the
  intake and the band only — never the period's average *budget*.
- `log_meal(description, grams=, kcal=, protein=, carbs=, fat=, slot=,
  confirm=False)` — **gated write**: with `confirm=False` it previews the
  resolved nutrition and target slot and mutates nothing; only `confirm=True`
  appends the entry. The gate is intrinsic — never add this tool to a
  permission allowlist, since a client's auto-approve mode would otherwise
  bypass the human confirmation.

The read tools deliberately never expose the raw daily budget number (only the
qualitative band), nor the sealed `.budget` file, the shared HMAC key, or the
sync token — the budget stays hidden by design.

Setup:

```bash
bash scripts/setup_mcp.sh   # create the venv and install diet_guard[mcp]
```

Then restart Claude Code in this repo and approve the project MCP server
(registered in `.mcp.json`).

## Development

```bash
python -m venv .venv && .venv/bin/pip install -r requirements.txt
.venv/bin/pre-commit install && .venv/bin/pre-commit install --hook-type pre-push
.venv/bin/python -m pytest diet_guard/tests/ --cov=diet_guard --cov-branch --cov-fail-under=100
```

See `CLAUDE.md` for scheduling details and production deployment gotchas,
and `docs/DOCS-design.md` for the original feature spec.