hegel-skill plugin
A plugin that teaches agents to write Hegel property-based tests for six languages and review them for weak spots
- 89 ★ on the repository
- Last commit
- MIT
Minimal access
Why this level
- The skill gives instructions and writes test files in the project. It touches files only and runs nothing itself.
Install
- Works in
In your terminal, with SkillFoxx CLI
npx skillfoxx add plugins/hegel-skillDetects the agents on your machine, shows the access level and pins the version.
Other ways to install
Access and checks
How we reviewMinimal accessThe tool runs nothing and makes no network calls.
- The skill gives instructions and writes test files in the project. It touches files only and runs nothing itself.
This is third-party code. Review the repository files before installing.
What it does
The plugin has two skills. The `hegel` skill guides an agent through writing property-based tests: Hegel generates random inputs and shrinks a failing case to a minimal counterexample. The agent must rely on evidence: documented contracts, names and signatures, invariants in the code and existing tests. One test checks one property and lives in the project ordinary test files. The skill tells the agent to check signatures against the library docs and source and never guess syntax. The second skill, `hegel-review`, checks finished tests against a list of weak spots: narrowed generators, fixed inputs posing as properties, no check in the reverse direction, several properties in one test, tolerances tuned to fit the result. Short guides sit in `skills/hegel/techniques/`: generators, running, scale, triage and adversarial review.
Who it is for. Developers on Rust, Go, C++, TypeScript, Java and OCaml who add property-based tests to a project and ask the agent not to write them as a formality.
Good fit when
- A function has a round trip such as serialize and parse, and it must be checked on hundreds of inputs
- A module has a contract with invariants and tests must exercise them over a wide domain
- Existing proptest or fast-check tests are reviewed for narrowed generators and tweaked tolerances
- A failing case needs triage: a real bug, or a test that demands more than the code promises
Not a fit when
- You want plain example tests with a few values, as the skill targets properties
- The language is outside the Hegel list, and the author allows value for other libraries but has not validated it
- Code with no contracts or invariants to derive properties from
Example request
Write Hegel property tests for the serialization functions in the codec module and review them with the hegel-review skillLimitations
The skill targets the Hegel libraries for Rust (`hegeltest`), Go, C++, TypeScript, Java and OCaml. The author has not validated usefulness for other property-based testing libraries. The skill does not guarantee that tests find every defect and does not replace human review. The agent learns the API from existing tests, docs and library source in the environment, so without access to them signatures must be supplied by hand. Installing with `$skill-installer` in Codex needs its built-in skill installer.
How to disable. Run `/plugin uninstall hegel-skill` in Claude Code or delete the `hegel` skill folder from the Codex skills directory.
FAQ
How do I install the plugin in Claude Code?
Run `/plugin marketplace add hegeldev/hegel-skill`, then `/plugin install hegel-skill@hegeldev`. Local installation is covered in the Claude Code skills docs.
How do I install the skill in Codex?
Run `$skill-installer install https://github.com/hegeldev/hegel-skill/tree/main/skills/hegel`. For other agents the install steps come from the docs of their skills.
Which phrases trigger the skill?
It reacts to requests to write tests and to the words "property-based tests", "PBT", "hegel", "fuzz" and "shrinking", and when a project already uses proptest, quickcheck, fast-check or jqwik.
What does hegel-review check?
Narrowed generators, fixed inputs posing as properties, a missing reverse direction, several properties in one test, evidence-free properties and tolerances widened to pass.
Do I need to know Hegel in advance?
No, the skill tells the agent to learn the API from existing tests, docs and library source first and to check the name and signature of everything it uses.
Discussion
No questions or reviews yet.
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README in short
The README briefly introduces the skill, its use with Claude Code, Codex and other agents and the install commands. The main content lives in `SKILL.md` and the `techniques/` guides.