Using Donner as a library from a consumer's point of view — the public SVG DOM API (SVGParser/SVGDocument/SVGElement/Renderer), the runnable examples/ programs, consuming Donner via Bazel module or the generated CMake mirror, Geode embedded (host-owned WebGPU device) mode, and the ECS-is-internal public-API boundary. Use when writing or reviewing code that parses/renders SVGs through the public API, when working in examples/ or examples/cmake_consumer/, when answering "how do I add Donner to my project", when editing docs/getting_started.md or docs/guides/embedding_geode.md, or when a change might leak ECS types (Registry, EntityHandle, EnTT) into a public header.
Run, scope, and configure Donner's Bazel build/test surface: choosing a --config, the variant lanes (*_tiny/*_text_full/*_geode), authoring BUILD.bazel targets with the donner_* macros, sanitizers (asan/ubsan/tsan), coverage, WASM/Emscripten builds, and the CMake mirror. Use when running bazel test/build, debugging a *_lint or variant-lane failure, adding or modifying BUILD.bazel targets, running the presubmit ritual before pushing a PR, or reading a sanitizer report.
PR lifecycle and CI triage playbook for Donner: the pre-push gate, PR hygiene rules (🤖 comment convention, no agent branding), the ~7-minute monitoring loop, merge rules, main.yml anatomy, and the transient-vs-real failure decision tree with artifact-driven diagnosis. Use when opening, updating, rebasing, or monitoring any PR; when responding to review comments; when a GitHub Actions check is red, hanging, or selected the wrong Bazel targets; or when deciding whether a PR is ready to merge.
Build, serve, test, package, security-review, deploy, verify, and roll back Donner's browser editor static site. Use when asked to build or host the Donner WASM editor; prepare the Geode or TinySkia web package; run browser parity tests; create or inspect an immutable deployment candidate; configure HTTPS, WebGPU, SharedArrayBuffer, COOP/COEP, MIME, CSP, or cache headers; publish the editor to a static host; or diagnose a deployed editor that is blank, not cross-origin isolated, or unable to load its pthread or WebGPU assets.
The mandatory red-to-green bug-fix workflow for Donner — write a failing repro test first, capture failure evidence, commit red then fix, and write diagnosable gmock-based tests (including perf repros with donner_perf_cc_test). Use when fixing any reported bug, writing a regression or perf test, preparing a commit that says "Fixes
Donner's C++ conventions with failure signatures - naming, destFromSource transform discipline, string types, the lifetimebound view-return footgun, banned patterns and the *_lint tests that enforce them, no-exceptions/no-std::any, Doxygen style, formatting commands, and no-dead-code/refactor-in-place. Use when writing, editing, or reviewing any C++ under donner/, or when fixing a *_lint test failure or a clang-tidy / clang-diagnostic-dangling error.
Authoring Donner design docs and Doxygen developer documentation — doc-type selection, numbering and collision protocol, the no-history and invariants-name-a-CI-target rules, DesignReviewBot gating, finalization stubs, and Doxygen page authoring/rendering traps. Use when creating, updating, reviewing, or finalizing anything under docs/design_docs/, writing or editing developer docs under docs/, adding a page to the Doxygen site, or running tools/doxygen.sh / tools/build_docs.sh.
Reproduce and root-cause Donner editor visual/interaction bugs via .rnr replay (editor_rnr_gl_replay), the editor-control MCP server, layer-by-layer escalation, and deterministic replay scheduling. Use when debugging one-frame glitches, overlay jumps, stale drag content, checkerboard flashes, wrong-scale textures, or element pop-backs; when an editor screenshot or .rnr replay is needed; or when driving or extending the editor-control MCP under tools/mcp-servers/editor-control/.