property-based-testing agent skill by trailofbits
Writes, reviews, and debugs property-based tests — Hypothesis, fast-check, proptest, jqwik, rapid, and Echidna or Medusa for Solidity invariants. Use whenever tests should cover a whole input domain instead of a hand-picked list of examples: encode/decode and serialize/deserialize pairs, parsers, canonicalizers and normalizers, validators, numeric and Decimal types, comparators and sort order, data structures, and smart-contract state invariants. Also use when adding cases to an existing @given, fast-check, or proptest suite, when judging whether existing property tests assert anything real, and when a generator has shrunk a counterexample and you need to tell a wrong property from a genuine bug. Not for coverage-guided binary fuzzing (libFuzzer, AFL), mutation-testing campaigns, static analysis, benchmarking, or end-to-end UI tests.
Source and license
| Publisher | trailofbits |
|---|---|
| Repository | trailofbits/skills |
| License | CC-BY-SA-4.0 |
| Snapshot | 2026-10-22 |
| Last repository commit | 2026-10-15 |
| Instruction size | 522 words; 62 lines |
| Bundled files | 9 |
Suede Skill Check: 89/100 · B
Report snapshot · · graded-v2
The rubric totals 100 points; published scores are capped at 99. Security scan: not scanned.
Source revision: 5c99c03fb8a9. Report version e4bae3e5b9f7. Badge URLs follow the latest listing; save the report to keep this version.
Download report · Request a fresh review
What to review next
- Example request: 0 of 3 points. 3 when the description quotes an example request (3–60 characters in quotation marks).
- Description length: 3 of 5 points. 5 for 150–600 characters; 3 for 100–900; 1 for 50–1,024.
- Bundled scripts: 0 of 2 points. 2 when the skill folder ships a scripts/ folder.
Add declarations and bundled files when they describe the skill’s actual needs. Update the source, then request a fresh review with the changed commit or PR.
| Component | Points earned | Available |
|---|---|---|
| Structural checks | 56 | 56 |
| Description length | 3 | 5 |
| Boundary clause | 4 | 4 |
| Example request | 0 | 3 |
| Instruction depth | 7 | 7 |
| Reference files | 3 | 3 |
| Bundled scripts | 0 | 2 |
| Recent maintenance | 9 | 9 |
| Curated-list citations | 7 | 7 |
| Tool permissions declared | 0 | 2 |
| Compatibility declared | 0 | 2 |
The published score is capped at 99. It measures the published files, documentation and maintenance signals. Security scan: not scanned. This assessment does not include a runtime test or a full installation-dependency review.
Install property-based-testing
The skills CLI works with Claude Code, Codex, Cursor and other agents; the other routes copy the folder by hand.
npx skills add https://github.com/trailofbits/skills/tree/main/plugins/property-based-testing/skills/property-based-testingtmp="$(mktemp -d)"
git clone --depth 1 https://github.com/trailofbits/skills.git "$tmp/repo"
mkdir -p .claude/skills
cp -R "$tmp/repo/"plugins/property-based-testing/skills/property-based-testing .claude/skills/
rm -rf "$tmp"tmp="$(mktemp -d)"
git clone --depth 1 https://github.com/trailofbits/skills.git "$tmp/repo"
mkdir -p .agents/skills
cp -R "$tmp/repo/"plugins/property-based-testing/skills/property-based-testing .agents/skills/
rm -rf "$tmp"For a user-level install, copy the folder to ~/.claude/skills/ (Claude Code) or ~/.agents/skills/ (Codex). Inside Codex, $skill-installer can also fetch a skill from GitHub. New to skills? Read How to install agent skills in Claude Code, Codex and Cursor.
trailofbits/skills is third-party code. Read SKILL.md and any bundled scripts before you install it.
Two badges for property-based-testing
Choose the numeric badge, the letter badge, or both. Each links to this skill’s Suede AI listing; either valid linked badge can qualify for the feature offer.
[](https://suedeai.directory/trailofbits/skills/property-based-testing/)
[](https://suedeai.directory/trailofbits/skills/property-based-testing/)<a href="https://suedeai.directory/trailofbits/skills/property-based-testing/"><img src="https://suedeai.directory/trailofbits/skills/property-based-testing/score.svg" alt="Suede Skill Check: 89/100" width="160" height="175"></a>
<a href="https://suedeai.directory/trailofbits/skills/property-based-testing/"><img src="https://suedeai.directory/trailofbits/skills/property-based-testing/badge.svg" alt="Suede Skill Check: Grade B" width="160" height="175"></a>Suede Certified on the shield refers to this published structural quality check. Security scan: not scanned. Read the methodology.
Limited-time feature offer: Display either quality badge in your repository or skill README, linked to your listing, then request verification. Suede AI checks the rendered README at a recorded commit. Eligible skills scoring 80–99 with a verified badge can receive a featured placement while the offer is open. Request badge verification.
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