effectcraft/CLAUDE.md

EffectCraft — instructions for agents

EffectCraft is a clean-room, open-source, pure-Rust motion graphics and visual effects compositor targeting Adobe After Effects parity (and beyond). Native on macOS, Windows, Linux; web via WASM. Sibling of ../photocraft (Photoshop), ../printcraft (Acrobat), ../vectorcraft (Illustrator), ../filmcraft (Premiere), ../lightcraft (Lightroom) and ../designcraft (InDesign), with the same conventions.

Start every session here

plan/ is maintainer-local (gitignored). Public equivalents: ROADMAP.md, docs/.

1. Read plan/STATUS.md (current milestone, next task, running agents, blockers).
2. Read the task in plan/execution-plan.md §3, the relevant section of plan/architecture.md, and the crate README/docs you touch. Feature ids: plan/aftereffects/feature-catalog.md; effects: plan/aftereffects/effects-list.md; UI reference: plan/aftereffects/README.md.
3. Read docs/gaps.md: the honest assessment of where we fall short and the prioritised workstreams. Fidelity, reliability and stability (G1–G3) come before new features.
4. Follow the autonomous operation protocol (plan/execution-plan.md §7). Don't stop to ask.

Non-negotiables

Read AGENTS.md first; its rules override everything here. No Adobe assets, every asset licensed + attributed (cargo xtask assets).

• Never crash (AGENTS.md "Never crash"; outranks feature work: a crash loses people's work). Non-test code has no unwrap()/expect()/panic!/unreachable!/todo!/unimplemented! and no unsafe: return Result and use ?, ok_or, let … else. Input-derived indices, slices and arithmetic use get() and checked/saturating math; recursion is depth-limited; locks handle poisoning. The app's last-resort guard turns an escaped panic into an error and keeps the document. Every crash fix gets a regression test. Standard: craftrules standards/never-crash.md.
• Clean-room. Behaviour and public docs only. No GPL/LGPL/AGPL code. ffmpeg only as an external test oracle.
• Pure Rust. Media codecs come from FilmCraft crates (git deps behind crates/media, see plan/adr/0001).
• Layering (cargo xtask layers): nothing below L5 depends on egui/eframe/winit/rfd/cpal; L0–L4 build for wasm32.
• Exact time: effectcraft_time::Tick (254 016 000 000/s). Keyframe times are layer time.
• Property tree: everything animatable is a Property in the layer's PropGroup tree, addressed by paths (transform/position, effects/#1/blurriness, @uid).
• Everything is a command (crates/engine): id, label, menu path, shortcut, params, enabled(), run(). UI, CLI, control channel and MCP dispatch by id.
• Everything is agent-drivable: every interactive widget registers an automation id; UI state is serde.
• Community links (Help menu, About, header Discord button): https://discord.gg/artcraft, https://getartcraft.com, https://getartcraft.com/apps/effectcraft, https://github.com/storytold/effectcraft.
• Quality gates before every commit: cargo xtask ci (fmt, clippy -D warnings, tests, layers, assets, wasm).
• Commits: one task id per commit (M6.3: trim paths). Only green states.

Running and looking at the app

• cargo run -p effectcraft -- --control 9877 opens the desktop app with the JSON-lines control server (docs/control-protocol.md).
• For UI work, look at the result. Headless (no window, works while the user is busy on the machine): cargo run -p effectcraft-ui-egui --example snapshot -- --out ui.png --step '{"method":"engine.execute","params":{"command":"layer.select","params":{"layers":["#2"]}}}' (steps are control-channel requests; --script steps.jsonl; {"method":"snap","params":{"path":…}} for intermediate shots). Or drive the live app via the control channel and take ui.screenshot (needs the window visible on screen).
• After Effects reference: drive AE via ExtendScript (osascript -e 'tell application "Adobe After Effects 2026" to DoScriptFile "x.jsx"') and capture only AE's window (screencapture -l <windowid>); keep captures in plan/aftereffects/ref/ (gitignored), never commit them, never capture the Home screen.
• Parallel agents: separate git worktrees and CARGO_TARGET_DIR=target/agent-<name>; keep every Cargo.toml valid (the crates/* glob).