Designs and improves fuzzing harnesses for C/C++ and Rust. Covers mapping raw bytes onto a target API, generating structured inputs, avoiding non-determinism and false crashes, and deciding what to fuzz together.
Install
npx skills add trailofbits/skills --skill harness-writingnpx skills add trailofbits/skills --skill harness-writing -a claude-code -gnpx skills add trailofbits/skills --skill harness-writing -a codex -ggemini skills install https://github.com/trailofbits/skills.git --path plugins/testing-handbook-skills/skills/harness-writinggh skill install trailofbits/skills harness-writinggit clone --depth 1 https://github.com/trailofbits/skills /tmp/trailofbits__skills
mkdir -p ~/.claude/skills ~/.agents/skills
cp -R /tmp/trailofbits__skills/plugins/testing-handbook-skills/skills/harness-writing ~/.claude/skills/harness-writing # Claude Code
cp -R /tmp/trailofbits__skills/plugins/testing-handbook-skills/skills/harness-writing ~/.agents/skills/harness-writing # Codex, Cursor, Gemini CLI, Copilot, OpenCode