harness-anchor

Use when sessions run long, adding subagents, fetching large files, or planning context-heavy work. SELECT/WRITE/COMPRESS/ISOLATE discipline.

Use before claiming "done", "fixed", "complete", "passing". Default-FAIL contract — every criterion needs evidence; express uncertainty if missing.

Use when the same mistake or bad pattern recurs, when a code-review comment is really a convention worth enforcing, or when you catch AI-generated drift/slop and want it to never happen again. Encodes the lesson as a durable rule in golden-rules.md — the feedback-flywheel / harness-layer-learning ratchet — instead of a one-off fix. Generic (language-agnostic).

Use when starting, advancing, finishing, or blocking a feature. Manages feature_list.json + progress.md + session-handoff.md. Default-FAIL enforced.

Use in C/C++ projects for crashes, hangs, UB, data races, memory errors. ASan/UBSan/TSan runtime checks. Build sanitizer config separately.

Use whenever working in a project. Establishes state/scope/verification discipline. Auto-loaded at session start. Complements superpowers.

Use in C/C++ projects when reviewing changes or hunting bugs. Runs clang-tidy/cppcheck/IWYU. Needs compile_commands.json. Changed lines only.

Use when a hook/tool returns a warning, lint/type/build error, or test failure after your edit. Iterate evidence-first; stop when verification passes.

Use when locating files or understanding structure. Consults PROJECT-TOC.md (one-line index per file). Staleness via git commit anchor.

Use at start of work, after env changes (deps/branch/OS), or when something stops working. Runs init.sh health check; treats failures as blocking.

Use when deciding what to test, reviewing whether a feature is adequately covered before calling it done, or when tests pass but you're unsure they exercise the real risks. Derives coverage obligations from code + spec, finds gaps (including paths outside the test runner's scope), and designs a minimal, edge-case-first test set. Dispatches the coverage-analyst subagent. Generic (language-agnostic).

Use when looking up unfamiliar tools, APIs, errors, library behavior. Context7 → WebSearch → calibrated uncertainty fallback chain. Don't guess.

Use in C/C++ projects for build configure/errors, compile_commands.json generation, or selecting CMake/Meson/Make/Bazel commands.

Use in C/C++ projects for clang-format. Changed-lines-only; never reformat unchanged code mid-feature. .clang-format from root or LLVM baseline.