The 15 Best Claude Code Skills for Engineers

An opinionated, battle-tested stack — the skills I load into every Claude Code install before touching a codebase. Each one encodes a staff-engineer workflow, not a prompt snippet.

npx skills add Hahaknight/claude-skills-pro  # installs the 7 free ones (MIT)

Full disclosure: I maintain this pack. 5 of the 15 are free and open source — take those and ignore the rest if you like. Here's how to write your own →

1. pr-reviewer FREE

Seven-dimension review (correctness, security, performance, contracts, error handling, tests, maintainability) with findings ranked Blocker / Should-fix / Nit. The anti-rubber-stamp: every finding carries file:line and a concrete fix.

Why it matters: the default review is a summary. This is a checklist with teeth.

2. bug-hunter FREE

Reproduce → bisect → single hypothesis → minimal fix → regression test. Explicitly bans shotgun patching (change three things, hope one works).

Why it matters: debugging is where AI burns the most time doing the least verifiable work. Forcing a reproducible failure first changes everything.

3. test-forge FREE

Generates boundary-value and failure-path tests, then runs a mutation self-check — kill the mutants or the tests aren't done.

Why it matters: "100% coverage" that catches nothing is the most common AI-testing failure.

4. feature-spec FREE

One page before any code: scope, non-goals, interface contract, edge-case table, test scenarios.

Why it matters: five minutes of spec saves five hours of wrong implementation.

5. commit-craft FREE

Splits tangled changes into logical commits, scans for leaked secrets before they land, writes messages that explain why.

Why it matters: your history is your team's long-term memory.

6. ai-code-reviewer PRO

Eight failure modes specific to AI-generated code: hallucinated APIs, behavior drift, over-engineering, silent contract breaks.

Why it matters: AI code needs a different review checklist than human code — the bugs are different.

7. security-audit PRO

Attack-surface audit from entry points and trust boundaries. Findings ranked by exploitability with fixes — not an OWASP vocabulary quiz.

8. db-migration-safe PRO

expand → migrate → contract three-phase migrations with lock-risk assessment for large tables.

Why it matters: this is the difference between a deploy and an outage.

9. refactor-surgeon PRO

Behavior-preserving refactors only: characterization tests first, small commits, any red test means roll back.

10. perf-profiler PRO

Measure → locate hotspot → fix → re-measure. Every conclusion ships with before/after numbers. No vibes-based optimization.

11. codebase-onboarding PRO

Builds a mental model of an unfamiliar repo in minutes, plus a "to add X, change Y" cheat sheet.

12. api-designer PRO

Error contracts, idempotency, cursor pagination, non-breaking evolution — designed for the consumer, not the implementer.

13. legacy-explainer PRO

Data-flow tracing through old code. Every claim carries file:line; inference is labeled separately from fact.

14. dep-guardian PRO

Risk-graded dependency upgrades and an admission review for new deps (activity, size, license).

15. changelog-release PRO

Semver computed from actual contract changes; release notes written from the user's point of view.

Get the stack: 5 skills free (MIT) · all 15 + CN handbook in the Pro pack

GitHub — free samples Full catalog →