# Contributing

## Prerequisites

- rust 1.85+ (edition 2024)
- sqlite development libraries

install the rust toolchain via [rustup](https://rustup.rs/) and make sure
sqlite headers are available for your platform.

## Development

```sh
cargo build
cargo test
cargo clippy
cargo fmt
```

run all checks before submitting changes:

```sh
cargo fmt && cargo clippy && cargo test && cargo build
```

### Database

data is stored in a sqlite file at `$XDG_DATA_HOME/todo/todos.db` (override
with `TODO_DB`). migrations in `migrations/` are applied automatically at
startup.

## Project layout

```
src/
  main.rs       - entry point
  cli.rs        - clap argument definitions
  commands.rs   - command handlers
  db.rs         - database access layer
  model.rs      - data types
  display.rs    - output formatting
  mcp.rs        - mcp server
tests/          - integration tests
migrations/     - sqlite migrations
build.rs        - shell completion generation
```

## Submitting changes

1. create a feature branch from `main`
2. keep commits small and focused
3. ensure `cargo fmt`, `cargo clippy`, and `cargo test` all pass
4. open a merge request with a clear description of what changed and why