pdfcraft/CLAUDE.md

PrintCraft — instructions for agents

PrintCraft is a clean-room, open-source, Rust-native PDF application targeting Adobe Acrobat Pro parity. It runs natively on macOS, Windows and Linux, and on the web via WASM. It is the sibling of ../photocraft (a Photoshop-class editor) and follows the same conventions.

Start every session here

1. Read plan/STATUS.md: the current milestone, the next unchecked task and any blockers. ROADMAP.md holds the milestone estimates and progress; update its table and log at the end of every session.
2. Read that task in plan/execution-plan.md §3, the relevant section of plan/architecture.md, and the README of the crate you're touching.
3. Follow the autonomous operation protocol in plan/execution-plan.md §7 (orient → plan → implement + test → verify → record → commit). Don't stop to ask unless §7 lists the decision as the user's.

plan/ is gitignored (local-only, like PhotoCraft). The machine-readable parity checklist lives in parity/ (committed).

Non-negotiables

• Assets: read AGENTS.md §1 before adding or showing any icon, image, font or document. No assets from Adobe products, ever. Only openly licensed or contributor-original assets are allowed, each with an entry in ATTRIBUTION.toml. cargo xtask assets enforces this. AGENTS.md overrides this file.
• Clean-room.
  • Never read, disassemble or copy anything inside the Acrobat bundle (names and listings only). Never open Contents/Resources/JavaScripts/.
  • Behaviour comes from public docs, specs (ISO 32000-2, the Arlington model) and black-box observation (plan/acrobat/).
  • Never copy GPL/AGPL code. MuPDF, Ghostscript, Poppler, veraPDF and DSS run only as external oracle processes.
  • See plan/README.md §Clean-room and plan/adr/0001.
• Privacy. When observing Acrobat, use synthetic fixtures only. Never capture the Home view, recent files or account info. Capture by window id (plan/acrobat/tools/). Never commit Acrobat outputs, corpus files or personal data.
• Layering. Nothing below L7 depends on egui/winit/eframe/rfd (plan/architecture.md §3). cos/filters/crypt/arlington stay standalone.
• Fidelity. The PDF object graph is the model. Preserve unknown data. Saves are incremental unless a full rewrite is required. Never silently drop or repair data without recording it.
• Never panic. Every PDF, script, MCP call, settings file and keystroke is untrusted input, and none of it may crash the app or lose the user's work. This outranks feature work. Return Result (the crate's error enum) and propagate with ?, or fall back leniently and record it. In non-test code:
  • No unwrap/expect/panic!/unreachable!/todo! unless it is provably infallible, with a comment saying why.
  • No indexing or slicing with input-derived positions (use get, and slice strings only at char boundaries).
  • Use checked or saturating arithmetic on input-derived numbers, and guard against division by zero and NaN/inf casts.
  • Cap allocations sized by input, and bound recursion with depth limits or seen-sets.
  • Handle lock poisoning.
  • No unsafe (unsafe_code = "forbid").
  • Every crash fix gets a synthetic regression test. See AGENTS.md §4 and craftrules/standards/never-crash.md.
• Rust only in the product and build (xtask). No handwritten JS/TS.
• Quality gates before every commit: cargo fmt --check, cargo clippy --workspace -- -D warnings, cargo test --workspace, and the wasm check once xtask ci exists (M0).
• Commits: one task id per commit (e.g. M1.4: xref stream reader). Commit only green states. End messages with the attribution line required by the environment.

Running and looking at the app

• cargo run -p printcraft -- <file.pdf> opens the desktop app.
• cargo run -p printcraft-cli -- run --script steps.json --root DIR drives the engine headlessly through the automation tools (printcraft-cli tools lists them). Use it, together with page_render, to check engine changes. printcraft-cli mcp is the opt-in MCP server (AGENTS.md §3).
• cargo xtask fuzz --time 300 mutation-fuzzes open/render/edit/save in child processes. Findings land in fuzz-out/findings/ (git-ignored; never commit corpus-derived files). Turn every real finding into a small synthetic regression test before fixing it.
• cargo xtask parity [--partial] reports Acrobat-parity progress from parity/acrobat-features.toml. Update the entry when a feature ships.
• cargo xtask demo-pdf builds dist/demo/printcraft-showcase.pdf (needs Chrome) for visual checks.
• For UI work, look at the result. Either launch printcraft --control FILE doc.pdf and use printcraft-cli ui --control FILE screenshot --out x.png (plus inspect, click, key, type, command, set), or take a headless shot with cargo run -p printcraft-ui-egui --example shot. Compare against plan/acrobat/02-ui-ux.md. Control-channel tests use kittest (crates/ui-egui/tests/control.rs).
• Parallel agents: use a separate CARGO_TARGET_DIR per agent and separate git worktrees.

Current bootstrap debt (tracked in STATUS.md)

• printcraft-render renders through the hayro crate directly and inspects documents through lopdf. Both get replaced by cos / model / the DisplayList device (M1–M2, ADR-0004).