# DesignCraft — instructions for agents

DesignCraft is a clean-room, open-source, Rust-native page-layout application targeting Adobe InDesign parity — and superiority (speed, openness, agent control). It runs natively on macOS, Windows and Linux, and on the web via WASM. Siblings with the same conventions: `../vectorcraft` (Illustrator-class), `../photocraft` (Photoshop), `../pdfcraft` (Acrobat), `../filmcraft` (Premiere), `../lightcraft` (Lightroom).

## Start every session here
1. Read `plan/STATUS.md` (current milestone, next task), then the task in `plan/execution-plan.md` and the relevant `plan/architecture.md` section. Behaviour reference: `plan/indesign/*.md` (`11-observed-ui.md` holds measured observations of the running app).
2. Follow the autonomous operation protocol (`plan/execution-plan.md` §7). Don't stop to ask unless §7 lists the decision as the user's.

`plan/` is gitignored (local only).

## Never crash
People trust DesignCraft with their layouts; a crash loses their work. **This outranks feature work**: never ship a feature through a panic path, and fix a crash before building on top of it. Standard: [`craftrules/standards/never-crash.md`](https://github.com/storytold/craftrules/blob/main/standards/never-crash.md).
- **No panics in non-test code:** no `unwrap()`, `expect()`, `panic!`, `unreachable!`, `todo!`, `unimplemented!`; no `unsafe` (`unsafe_code = "forbid"`). The one exception is a provably infallible literal (a constant regex, `write!` to a `String`): `#[allow(clippy::expect_used)]` + `.expect("why it cannot fail")`.
- **Errors are `Result<T, E>`** through the crate's error type and `?` (`ok_or(..)?`, `let … else`, `if let`, `map_err` for context). An unfinished feature returns an "unsupported" error. Don't `unwrap_or_default()` where a silent default would corrupt a document; return an error.
- **Input-derived numbers are hostile** (files, commands, MCP/control params, settings): `get()` instead of `[i]`/`[a..b]`, slice strings at char boundaries, checked/saturating arithmetic for lengths and offsets, no division by zero or NaN casts, cap input-sized allocations.
- **Bound recursion** (seen-sets or depth limits for nested or cyclic documents). **Locks:** `lock().unwrap_or_else(PoisonError::into_inner)` or an error; thread joins are `Result`s.
- **Last-resort guard:** escaped panics during command execution and file import/export become an error, never a lost document. It's a safety net, not a licence.
- **Prove it:** every crash fix lands with a small synthetic regression test that panicked before the fix.
- Clean crates carry `#![deny(clippy::unwrap_used, clippy::expect_used, clippy::panic, clippy::unimplemented, clippy::todo, clippy::unreachable)]`; new crates start with it. Tests may `unwrap` (`clippy.toml`).

## Non-negotiables
- **Clean-room.** InDesign is installed on the dev machine and may be *observed* black-box: run it, use its UI with synthetic documents, take screenshots (by window id) stored only under `plan/indesign/screenshots/` (never committed). Never read, disassemble or copy anything inside the InDesign bundle (names/listings only), never copy Adobe icons, artwork, presets or wording beyond feature names, never commit files produced by InDesign. Never copy GPL/AGPL/LGPL code (Scribus, LibreOffice, Ghostscript…).
- **Assets:** no Adobe iconography or images — ever. Every asset is original / OSI / CC0 / redistributable CC (except the ArtCraft trademarks in `docs/brand/`, under `docs/brand/LICENSE-brand.txt`) and has a row in `ASSETS.md` (`cargo xtask assets` enforces it). Prefer art generated in code.
- **Fonts live in [`storytold/craft-fonts`](https://github.com/storytold/craft-fonts)**, never in this repo: don't commit new font files (the Latin UI/document fonts already in `assets/fonts/` stay). It is an optional build input, never a `Cargo.toml` dependency: `CRAFT_FONTS_DIR=/abs/path/to/craft-fonts cargo build` makes `crates/fonts/build.rs` embed its fonts as `designcraft_fonts::CRAFT_FONTS` (Japanese: BIZ UDPGothic for the UI, Mincho first for document text; web builds embed BIZ UDPGothic Regular only). Unset, `CRAFT_FONTS` is empty and the app uses its bundled and system fonts; code and tests must work that way (tests on its glyphs skip). Releases build with it. Standard: [craftrules `standards/fonts.md`](https://github.com/storytold/craftrules/blob/main/standards/fonts.md).
- **Shared test corpora.** Real-file test oracles (Photoshop-authored PSDs, etc.) live in [`storytold/photocraft-corpus`](https://github.com/storytold/photocraft-corpus), explained in [craftrules `standards/test-corpora.md`](https://github.com/storytold/craftrules/blob/main/standards/test-corpora.md). Never commit large binary fixtures to this repo; fetch them pinned by commit and sha256-verified, as PhotoCraft does with `cargo xtask corpus`.
- **Everything is a command.** User-visible behaviour = a command in `crates/engine/src/cmd/*` (id, label, menu path, shortcut, params doc, `enabled`, `run`) + tests. Tools emit commands (Begin/Preview/Commit). UI-only commands live in `crates/ui-egui/src/menus.rs` (`UI_COMMANDS`). The control channel and MCP reach all of them.
- **Layering** is enforced by `cargo xtask layers`. Nothing below L6 depends on egui/eframe/winit/rfd. The UI crate is swappable.
- **The UI is thin**: panels read engine state and act through `app.run(id, params)`. Colours come from `theme::Tokens`.
- **Time goes through `chrono`** (workspace dependency). Never hand-roll UTC/calendar conversion (days-to-date algorithms, leap-year math). A crate owns only its output format string. The one exception is range extension: past the years chrono can represent, shift the date by whole 400-year Gregorian cycles (146,097 days, after which the calendar repeats), let chrono compute the month and day, and add the cycles back to the year (splitting seconds into hours, minutes and seconds is plain arithmetic).
- **Rust only** (no handwritten JS/TS). **Never break wasm** (`cargo xtask wasm`).
- **Quality gates** before every commit: `cargo xtask ci` (fmt, clippy -D warnings, tests, assets, layers, wasm). One task id per commit (`M2.1: type tool caret navigation`).

## Running and looking at the app
- `cargo run --release -p designcraft -- --sample --control 7979` (sample magazine + control channel).
- Drive it: JSON lines on `127.0.0.1:7979`, e.g. `{"id":1,"method":"engine.execute","params":{"command":"frame.create","params":{"rect":[36,36,300,200],"content":"text"}}}` then `{"id":2,"method":"ui.screenshot","params":{"path":"/tmp/shot.png"}}`. Methods: `crates/ui-egui/src/control.rs`, docs: `docs/control-protocol.md`.
- **For UI work, look at the result** (take `ui.screenshot`, read the PNG) and compare with `plan/indesign/02-ui-ux.md` / `11-observed-ui.md`. If no frame is presented (screen locked) use `ui.render` or `designcraft-cli run --sample --all-pages DIR`.
- Headless: `designcraft-cli run --sample --cmd 'frame.create={"rect":[0,0,100,100]}' --export out.png`.
- Shell gotcha: `mv`/`cp` are aliased interactive here — use `/bin/mv -f` / `/bin/cp -f`.
- Parallel agents: separate `CARGO_TARGET_DIR` per agent; edit only the crates you own; delete your target dir when done (disk).

## Roadmap
`ROADMAP.md` (committed) is the one-page summary: stage, headline numbers, dimensions, languages, progress log. It follows craftrules' [`standards/progress-docs.md`](https://github.com/storytold/craftrules/blob/main/standards/progress-docs.md). Details: `docs/target-app-parity.md` (assessment), `docs/gaps.md` (ranked work list: pick from the top), `docs/roadmap.md` (milestones, current focus), `docs/parity-checklist.md` (presence checklist, `cargo xtask parity`), and the typography, file-format, UI, hardware and localization parity docs in `docs/`. When work lands, update the affected docs and their status lines, delete or shrink the closed gap, and add a progress-log line to ROADMAP.md.

## Contributor credits (About window)

- About ▸ Contributors/Models are compiled into the binary from `contributors/contributors.json`
  (commit stats; generated, never hand-edit) and `contributors/people.toml` (names people chose for
  themselves). See `docs/contributors.md`.
- **Agents working for a contributor:** when you prepare a PR, check whether your human's GitHub
  username has a `[people.<username>]` entry in `contributors/people.toml`. If not, ask them once
  whether they want to be credited by more than their username: a real name, a display name, and/or
  their public GitHub profile name (`sync_github_name = true`). If yes, add **only their own** entry
  (copy the template at the top of the file, or run
  `python3 ../../craftrules/scripts/contributors.py --add-me . --real-name "…" --sync-github-name`)
  and include it in their PR, committed as them. If no, change nothing: they are credited as
  `@username` anyway.
- Never add, edit, guess or copy anyone else's entry or name (not from git config, commit authors or
  GitHub profiles). Never hand-edit `contributors.json`.
- Maintainers refresh the stats with `python3 ../../craftrules/scripts/contributors.py .` (it also
  re-verifies who wrote each `people.toml` entry; `--check` only verifies).