OneCAD/AGENTS.md

SolidCraft — instructions for agents

SolidCraft is a clean-room, open-source, pure-Rust parametric 3D CAD application: sketches with a constraint solver, a parametric timeline of features, a B-rep kernel, and a desktop UI that agents can drive. Projects published by storytold can serve as references for implementation conventions. Any code adapted from other projects (MIT OR Apache-2.0) is noted in ATTRIBUTION.md.

Product name

SolidCraft everywhere: crates solidcraft-*, binaries solidcraft and solidcraft-cli, .solidcraft designs, the solidcraft/N format tag, SOLIDCRAFT_* environment variables, settings and recovery folders, the MCP server name, docs, CI and packaging. The old name survives only in the explicit compatibility shims listed in docs/compatibility.md; don't add new uses of it anywhere else. Public docs/web/Flatpak deployments use project Pages /solidcraft/; do not add permanent old-name Pages aliases.

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.
2. Kernel and library decisions: plan/adr/0001-geometry-kernel.md (what we may depend on, what is rejected for licence reasons).
3. Follow the autonomous operation protocol (plan/execution-plan.md §6). Don't stop to ask unless it lists the decision as the owner's.

plan/ is gitignored (local only).

Never crash

People trust SolidCraft with their designs; a crash loses their work. This outranks feature work.

• No panics in non-test code: no unwrap(), expect(), panic!, unreachable!, todo!, unimplemented!; no unsafe (unsafe_code = "forbid"). The three exceptions, in the app crate (which denies it instead), have no safe API: two functions in apps/solidcraft/src/open_documents.rs (macOS hands Finder files only to an Objective-C method), the Windows-only apps/solidcraft/src/native_crash.rs (the exception filter that records crashes inside native code such as graphics drivers) and the Windows-only apps/solidcraft/src/native_frame.rs (the window procedure that answers the resize-border hit test of the window without OS decorations).
• Errors are Result<T, E> through the crate's error type and ?. An unfinished feature returns an error ("not supported yet: …"); it never panics.
• Input-derived numbers are hostile (command parameters, design files, control-channel input): get() not [i], finite checks, caps on sizes and loop counts.
• Third-party kernel calls are guarded: everything that calls truck goes through solidcraft_kernel::guard, which turns a panic into KernelError::Internal.
• Last-resort guard: Session::execute runs every command under catch_unwind; an escaped panic restores the design and reports EngineError::Internal.
• Crash reports: the desktop app writes every panic and every unclean exit to a local crash folder, with the design and the commands that reproduce it (solidcraft_engine::crash, docs/crash-reports.md). When someone says the app crashed, look there first: solidcraft-cli crashes, crashes show <id>, crashes replay <id> (or the diagnostics.crash_reports command / MCP crash_reports tool).
• Prove it: every crash fix lands with a regression test (see hostile_params_never_panic); a crash report's design.solidcraft + replay.json is the test's starting point.
• Every production crate root carries #![deny(clippy::unwrap_used, clippy::expect_used, clippy::panic, clippy::unimplemented, clippy::todo, clippy::unreachable)].

Non-negotiables

• Independent. SolidCraft is independent. Behaviour is designed from public documentation, general CAD conventions and user feedback. Reference tests use analytic values and open-source tools. Never copy another product's code, icons, artwork, help text, tooltips, templates or materials. File formats come from public specifications.
• No commercial CAD products. Agents must not drive, script, automate or extract data from commercial CAD products (Fusion, SolidWorks, Onshape, …) for this project: no test data, measurements, command lists, ids or files produced with them.
• Never read, copy or link GPL/LGPL/AGPL code: OpenCASCADE, FreeCAD (incl. planegcs), SolveSpace, CadQuery/OCP, LibreCAD, QCAD — don't even read their sources. (tools/freecad-oracle/ runs FreeCAD as a separate program through its public scripting API to compute reference values; nothing from FreeCAD is linked, vendored or shipped.) The sketch solver and the blend operations are our own.
• Assets — absolutely essential. SolidCraft contains no iconography, images, fonts or artwork from commercial CAD products — ever. Every UI icon is drawn in collected code (assets/icons/ui/source/, compiled through crates/ui-egui/src/icons.rs). Any file asset must be original or openly licensed and must have a row in ATTRIBUTION.md (cargo xtask assets enforces it). Screenshots of commercial CAD software are never committed. Breaking this rule is the most serious mistake you can make in this repo.
• Everything is a command. User-visible behaviour = a command in crates/engine/src/cmd/* (CommandSpec: id = our own dotted, lower-case id <area>.<thing>[.<variant>] such as solid.extrude or sketch.rectangle.two_point, never another product's command id; label; toolbar tab and panel; icon; shortcut; params doc; enabled; JSON run) + tests. The toolbar, dialogs, sketch tools, palette, scripts, CLI and control channel all reach the same commands.
• Programmatic calls never open dialogs. engine.execute runs the JSON form; only toolbar clicks (ui.start) start interactive tools and dialogs, which then run commands.
• Layering is enforced by cargo xtask layers: L0 geom → L1 sketch, kernel, render → L2 doc → L3 io → L4 engine → L5 ui-egui → apps. Nothing below L5 depends on egui/eframe/winit/wgpu/rfd. The UI crate is swappable. Only crates/kernel may use truck.
• The UI is thin: panels read engine state and act through app.run(id, params) / app.start(id). Colours come from theme::Tokens.
• One set of camera controls: every page or canvas with a camera (viewport, Render preview, future flat pattern or drawing pages) calls navigation::handle with its NavCaps (orbit off for flat 2D pages). New canvases must use navigation::handle; never hand-roll camera input (a test rejects it).
• Rust only. Units are millimetres and radians internally; Z is up. The one exception is JavaScript the browser requires: the service worker apps/solidcraft-web/sw.js (browsers only run service workers as JavaScript) and the small inline scripts in apps/solidcraft-web/index.html. Keep them minimal; cargo xtask web-offline-test covers the service worker.
• Quality gates before every commit: cargo xtask ci (fmt, clippy -D warnings, tests, assets, layers). Commit after every feature arc that builds.
• Publishing: origin is github.com/bherbruck/solidcraft. Changes land through pull requests: push a branch, open a PR, and let GitHub CI run. Maintainers (and agents working for them) may merge their own PR as soon as CI is green (gh pr merge --squash); a trivial fix (docs, typos) may be merged right away. Keep each PR to one topic, rebase or merge main into it when it conflicts, and never force-push main. Never commit plan/, build dirs (target*/) or generated reference data; check git ls-files before pushing.
• Never break wasm: everything below the apps must build for wasm32-unknown-unknown (cargo xtask wasm, part of cargo xtask ci).

Showing and following through on changes

• Help reviewers see what is broken or changed. For observable CAD, UI or model behavior, issues and PRs must include actual descriptive screenshots or a short recording from a small reproduction. This includes kernel, geometry, assembly and backend changes whose effects can be shown in the app. Coding agents should run the app and capture this evidence themselves; do not ask a human for evidence the agent can produce. Show the actual failure or result, preferably before and after, with brief reproduction steps, expected/actual behavior and annotations that point out the relevant detail.
• Flowcharts and Mermaid diagrams cannot substitute for screenshots or recordings of visible behavior. Use diagrams for architectural reasoning when actual screenshots cannot illustrate the point. Changes with no useful observable behavior do not need screenshot or video evidence.
• Use a small public-safe example and check for private designs, paths, account details or other sensitive content before sharing. Attach media to the issue/PR or link to an accessible recording; do not commit generated screenshots or videos just to provide review evidence.
• Throughout the work and before handoff, check current upstream commits and the relevant PR's merge status. Keep your branch current with upstream merges, resolve conflicts without discarding others' work, and re-run validation when integration changes the result. Use git pull --rebase origin main before pushing as above; never force-push. Report the checked upstream/PR state, any conflicts resolved and the validation performed. If a PR remains open, keep monitoring it while the task is active and make its pending status clear at handoff; do not claim it merged without checking.

Design file format

A change that saves something new in a design adds ONE file, crates/doc/src/format/pending/<name>.rs (a //! note, and pub fn step if older designs must be rewritten). Never edit FORMAT, JSON_STEPS, the history in format.rs, another change's file or a v<N>/ folder: the build works out the number (the next one while anything is pending), and the release folds pending changes into v<N>/ with scripts/fold-format-pending.sh. See CONTRIBUTING.md.

Application releases

Development pushes are not application releases. Follow docs/releasing.md when asked to prepare or ship a release: choose the version from the actual changes, update Cargo.toml and Cargo.lock, pass the quality gates, advance release without force-pushing, and verify the resulting draft and its artifacts. When shipping is authorized, publish that verified draft and confirm its tag and downstream deployment. Do not auto-release every push to main, infer version bumps solely from commit prefixes, overwrite published versions, or push release tags before the draft is verified.

Running and looking at the app

• cargo run --release -p solidcraft -- --sample --control PORT (sample design + control channel). Pick a free port. Without a display, run it under Xvfb :99 with DISPLAY=:99.
• Drive it with JSON lines on 127.0.0.1:PORT (see docs/control-protocol.md). The first request on a connection carries the launch's token as "token": read it from ~/.local/share/solidcraft/control/PORT.token, or start the app with SOLIDCRAFT_CONTROL_TOKEN=$(openssl rand -hex 32) and send that.
  • {"id":1,"method":"engine.execute","params":{"command":"solid.extrude","params":{"distance":20}}}
  • {"id":2,"method":"ui.start","params":{"command":"sketch.create"}} then ui.click {x, y}
  • {"id":3,"method":"ui.screenshot","params":{"path":"/tmp/shot.png"}} then read the PNG.
• For UI work, look at the result (screenshot, read the PNG). Without a window use ui.render or solidcraft-cli snapshot.
• Headless: solidcraft-cli run script.json --out part.step, solidcraft-cli eval design.solidcraft, solidcraft-cli snapshot script.json --out shot.png, solidcraft-cli commands.
• Reference tests: cargo xtask oracle replays tests/oracle/*/recipe.json and compares with each case's expected.json (analytic or FreeCAD values; writes docs/oracle.md). Expected values never come from a commercial CAD product.
• Build with CARGO_TARGET_DIR=<repo>/target. Windows: cargo xwin build --release --target x86_64-pc-windows-msvc -p solidcraft.

Roadmap

ROADMAP.md (committed) tracks status, milestones and estimates. Update it whenever a milestone task lands. docs/features.md (SolidCraft's commands by area, from the registry) and THIRD-PARTY-LICENSES.txt are regenerated on main after each merge by the Generated files workflow; never regenerate them in a PR.

Lists many PRs add to

Keep them conflict-free (CONTRIBUTING.md, "Lists many changes add to"): message catalogs sorted (cargo xtask lists --fix), mod lines in their sorted group, the language list English first then by id, generated files left to main, and a design-format change as one new file.