Implement, test, diagnose, review, and improve code with evidence.
code-review
Code review discipline: the approval bar is "improves code health," not "perfect," Fowler's code-smell catalog gives design/complexity concerns a name instead of a vague feeling, and small PRs keep review depth from degrading. Use when reviewing a pull request or diff, requesting a review, deciding whether a change is blockable, or leaving review feedback.
Open SKILL.md ↗code-style-lint
Discipline for code style and static analysis, adopt the ecosystem's established formatter as the non-negotiable source of truth, enforce it at pre-commit and CI rather than in review, and treat linting (real defects) as a separate concern from formatting (appearance). Use when setting up a new project's tooling, when a code review comment is about whitespace/naming/formatting instead of behavior, or when the user asks how to configure a linter or formatter.
Open SKILL.md ↗diagnosing-bugs
Systematic debugging discipline based on David Agans' nine rules, understand the system, reproduce reliably, bisect the search space, change one variable at a time, keep an audit trail, and never declare a fix done until it's verified against the original failure. Use when the user reports something broken, throwing, failing, or slow, or says "diagnose" / "debug this".
Open SKILL.md ↗improve-codebase-architecture
Scan a codebase (or a named area of one) for architectural friction, classify each finding by how it was incurred, and propose deepening opportunities in priority order. Use when the user wants an architecture review, asks where the design is causing pain, wants technical debt surfaced and prioritized, or asks what to refactor next.
Open SKILL.md ↗resolving-merge-conflicts
Discipline for resolving an in-progress git merge or rebase conflict, a conflict marker names two divergent intents from a shared ancestor, resolved by tracing each side back to what it was trying to accomplish, never by blindly picking one side's raw text. Use when a merge or rebase has stopped with conflict markers, when deciding whether to resolve with --ours/--theirs, or when choosing between merge and rebase for integrating a branch.
Open SKILL.md ↗secure-coding
Secure-coding discipline mapped to the OWASP Top 10, checked at the point of writing code, not after. Covers input validation and injection classes, broken access control, secrets handling, dependency/supply-chain risk, and safe error handling/logging. Use when writing code that crosses a trust boundary (handles user input, auth, payments, file paths, external commands, or third-party dependencies), when reviewing a diff for security issues, or when the user asks for a security review, threat check, or "is this safe."
Open SKILL.md ↗tdd
Test-driven development discipline: the red-green-refactor cycle, the testing pyramid's proportion of unit/integration/e2e, Fowler's test-double taxonomy, and the FIRST properties of a test worth keeping. Use when building a feature or fixing a bug test-first, mentions "TDD" or "red-green-refactor", or when deciding what kind of test to write, whether to mock a dependency, or how a test suite should be shaped.
Open SKILL.md ↗test-strategy
Suite-level testing decisions that sit above individual tests, where test data comes from (synthetic factories vs anonymized production snapshots), the flaky-test quarantine policy, and where the integration/e2e boundary actually belongs. Use when deciding how a test suite should source its data, what to do with a flaky test, or whether a given seam needs a full integration test, a contract test, or a unit test with a double is enough. Does not cover the red-green-refactor cycle or test-double taxonomy; see the tdd skill for those.
Open SKILL.md ↗