Writes documentation for test cases — names, docstrings, and comments that explain what behavior is being tested and why, so a failing test tells you what broke without reading the assertion. Use when test names are test_1 through test_47, when tests fail and nobody knows what they mean, or when onboarding needs a readable test suite.

Generates pytest regression tests that capture current behavior as snapshot assertions, using Python's dynamism for low-friction recording. Use before refactoring untested Python, when the behavioral spec is "whatever it does now," or when migrating Python 2→3 or between framework versions.

Compares two versions of a requirements document and reports additions, removals, semantic changes, and scope drift — distinguishing clerical edits from meaning changes. Use when a spec was revised, when checking if a new version of a standard affects you, or when the user asks what changed between spec versions.

Transforms a changelog or commit range into user-friendly release notes with highlights, upgrade guidance, and narrative framing. Use when publishing a release announcement, when the changelog is too dense for users to read, or when the user needs a blog-post-shaped summary of a version.

Assists migrating a build or CI pipeline from one system to another — Jenkins to GitHub Actions, Travis to GitLab CI, Makefile to Bazel — preserving semantics and surfacing untranslatable constructs. Use when switching CI providers, when modernizing a legacy build, or when the user pastes a Jenkinsfile and asks for the GitHub Actions equivalent.

Builds a bidirectional traceability matrix linking requirements to design elements, code, and tests — so every requirement traces forward to its implementation and every test traces back to its justification. Use for compliance audits, when answering why a piece of code exists, or when checking that nothing was built without a reason.

Identifies recurring structural patterns in a codebase — idioms, copy-paste clones, homegrown abstractions — and characterizes each as a reusable template. Use when learning a codebase's conventions, when hunting for copy-paste that should be a function, or when documenting how this team does things.

Translates cryptic runtime error messages and stack traces into understandable explanations, pointing to the concrete line at fault and the most likely fix. Use when a user pastes an error they don't understand, when a stack trace is deep and the user doesn't know where to start, or when an error message misleads about the real cause.

Translates Python into Lean 4 for interactive theorem proving, handling dynamic types and duck typing by specializing to the concrete types actually used. Use when proving correctness of a Python algorithm beyond what testing can establish, or when building a verified reference for numerical or combinatorial Python code.

Raises test coverage by identifying uncovered code regions, ranking them by risk, and generating targeted tests that hit them — prioritizing branches and conditions over raw line count. Use when coverage is below target, when untested code is blocking a release, or when deciding which tests to write next.

Reviews and designs API contracts — function signatures, REST endpoints, library interfaces — for usability, evolvability, and the principle of least surprise. Use when designing a new public interface, when reviewing an API PR, when the user asks whether a signature is well-designed, or when planning a breaking change.

Generates concrete scenarios from a requirement — happy paths, edge cases, and error conditions — expressed as Given/When/Then or equivalent structured narratives. Use when turning a requirement into acceptance tests, when exploring what could go wrong, or when the requirement is abstract and needs grounding.

Detects ambiguity in natural-language requirements — weak words, dangling references, underspecified quantities, conflicting interpretations — before they become implementation bugs. Use when reviewing requirements, when a spec uses words like "appropriate" or "fast", or when two engineers read the same requirement and built different things.

Generates CI pipeline configs by analyzing a repo's structure, language, and build needs — GitHub Actions, GitLab CI, or other platforms. Use when bootstrapping CI for a new repo, when porting from one CI to another, when the user asks for a pipeline that builds and tests their project, or when wiring in security gates.

Generates a structured CHANGELOG.md from VCS history and PR/issue references, categorized by change type. Use when cutting a release, when the user asks to update CHANGELOG.md, or when backfilling a changelog from git history.

Translates specifications into temporal logic formulas (LTL, CTL, or TLA) by matching the specification's shape to the right logic and operators. Use when formalizing requirements for any model checker, when choosing between LTL and CTL for a property, or when the user has a temporal claim and doesn't know which operators express it.

Orders tests so failures surface earliest — runs tests covering changed code first, historically flaky/failing tests early, and slow low-value tests last. Use when the suite is too slow to run in full on every change, when CI feedback takes too long, or when deciding what to run in a smoke-test tier.

Produces natural-language summaries of what code does at the function, class, module, or subsystem level, with length and abstraction scaled to the scope. Explains purpose, side effects, and non-obvious behavior rather than restating syntax. Use when onboarding to unfamiliar code, when the user asks what something does, when generating docstrings or architecture notes, or when preparing a handoff document.

Compares the runtime behavior of two or more versions of the same code by running them on identical inputs and diffing outputs, side effects, and errors. Use when validating a refactor, port, or optimization; when the user asks if two implementations behave the same; or when investigating a suspected regression across versions.

Audit any website for AI/agent-friendliness using AgentLint. Run `npx @cjavdev/agent-lint` with a URL to scan a site across 17 rules in 5 categories (transport, structure, tokens, discoverability, agent), get a 0-100 AgentScore with letter grade, and receive a prioritized remediation plan. Use this skill when: auditing a site for AI readiness, checking if a site has llms.txt or markdown support, improving a website's agent-friendliness score, fixing AgentLint violations, or understanding what makes a site AI-friendly. Trigger phrases: 'run agentlint', 'audit site for AI', 'check agent-friendliness', 'agentlint scan', 'AI-friendly audit', 'check llms.txt', 'agent readiness'.