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coverage-analysis
80 / 100 · Low risk
Fine to try.
By trailofbits/skills (GitHub) · marketing · 8,130 stars · scanned at commit e4dd0bb
Measures and interprets what a fuzzing campaign actually reaches, using llvm-cov, lcov, or a fuzzer's own coverage output. Covers baselining a new campaign, reading coverage reports, and turning uncovered regions into harness, seed, or dictionary work. Use when a fuzzer plateaus, when judging whether a harness is effective, after changing a harness, or when asking why some code is never reached.
Works with any agent that supports SKILL.md skills.
What this skill can do
Runs commands on your computer
The author does not mention this.
Found in 26 places.
Show 17 more
- plugins/testing-handbook-skills/skills/coverage-analysis/SKILL.md, line 181
LLVM_PROFILE_FILE=fuzz.profraw ./fuzz_exec corpus/ - plugins/testing-handbook-skills/skills/coverage-analysis/SKILL.md, line 186
./fuzz_exec_gcov corpus/ - plugins/testing-handbook-skills/skills/coverage-analysis/SKILL.md, line 197
llvm-profdata merge -sparse fuzz.profraw -o fuzz.profdata - plugins/testing-handbook-skills/skills/coverage-analysis/SKILL.md, line 214
uv tool install gcovr - plugins/testing-handbook-skills/skills/coverage-analysis/SKILL.md, line 226
cargo install cargo-binutils rustfilt - plugins/testing-handbook-skills/skills/coverage-analysis/SKILL.md, line 287
./fuzz_exec corpus/ # Crashes on bad input, no coverage generated - plugins/testing-handbook-skills/skills/coverage-analysis/SKILL.md, line 340
cmake -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ . - plugins/testing-handbook-skills/skills/coverage-analysis/SKILL.md, line 363
./fuzz_exec_gcov corpus_batch_1/ - plugins/testing-handbook-skills/skills/coverage-analysis/SKILL.md, line 381
llvm-cov show ./fuzz_exec -instr-profile=fuzz.profdata /path/to/src/ - plugins/testing-handbook-skills/skills/coverage-analysis/SKILL.md, line 386
llvm-cov show -show-directory-coverage -format=html -output-dir html/ - plugins/testing-handbook-skills/skills/coverage-analysis/SKILL.md, line 391
llvm-cov export -format=lcov > coverage.json - plugins/testing-handbook-skills/skills/coverage-analysis/SKILL.md, line 400
LLVM_PROFILE_FILE=campaign1.profraw ./fuzz_exec corpus1/ - plugins/testing-handbook-skills/skills/coverage-analysis/SKILL.md, line 433
clang++ -fprofile-instr-generate -fcoverage-mapping \ - plugins/testing-handbook-skills/skills/coverage-analysis/SKILL.md, line 440
LLVM_PROFILE_FILE=fuzz.profraw ./fuzz_exec corpus/ - plugins/testing-handbook-skills/skills/coverage-analysis/SKILL.md, line 457
clang++ -fprofile-instr-generate -fcoverage-mapping \ - plugins/testing-handbook-skills/skills/coverage-analysis/SKILL.md, line 463
AFL_USE_ASAN=0 afl-gcc -ftest-coverage -fprofile-arcs \ - plugins/testing-handbook-skills/skills/coverage-analysis/SKILL.md, line 470
LLVM_PROFILE_FILE=fuzz.profraw ./fuzz_exec afl_output/queue/
and 6 more places
Downloads and installs other software
The author does not mention this.
Found in 2 places.
Install
Paste this into your terminal. It downloads exactly the version we scanned, not whatever is newest.
if [ -e ~/.agents/skills/'coverage-analysis' ] || [ -L ~/.agents/skills/'coverage-analysis' ]; then echo 'A skill folder named coverage-analysis already exists — not replacing it' >&2; false; else d=$(mktemp -d) && git clone --quiet --filter=blob:none --no-checkout 'https://github.com/trailofbits/skills' "$d" && git -C "$d" checkout --quiet 'e4dd0bb5b15535f7c5a0834187dffba6ac37e4ff' -- 'plugins/testing-handbook-skills/skills/coverage-analysis' && mkdir -p ~/.agents/skills && cp -R "$d"/'plugins/testing-handbook-skills/skills/coverage-analysis' ~/.agents/skills/'coverage-analysis' && rm -rf "$d"; fi
Codex reads ~/.agents/skills directly. For Claude Code, Cursor, Copilot, Gemini CLI, Antigravity or OpenCode, also link it. For Claude Code: ln -s ~/.agents/skills/'coverage-analysis' ~/.claude/skills/'coverage-analysis' (other agents: ~/.cursor/skills, ~/.copilot/skills, ~/.gemini/skills, ~/.gemini/config/skills, ~/.config/opencode/skills). Or install through the finder skill, which does both.
Badge for your README
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Score history
| Date | Version | Score |
|---|
| 2026-11-08 | e4dd0bb | 80 |
| 2026-11-07 | e4dd0bb | 80 |