Coding

Writing Skills for Claude Code

How to author a SKILL.md that Claude Code will discover, load, and apply correctly.

Use when: User wants to author a new Claude Code skill, or is asking how SKILL.md files should be structured.

TypeScript Strict Mode Expert

Enforces strict TypeScript patterns: no any, explicit return types, exhaustive switch, and discriminated unions.

Security-First Development

OWASP-aligned security rules: input validation, auth patterns, secrets handling, and XSS prevention.

React Best Practices Guardian

Enforces modern React patterns: server components, proper hooks usage, and performance-first composition.

Tailwind CSS Architecture

Opinionated Tailwind CSS rules: utility-first, design tokens, responsive patterns, and dark mode.

Git Commit Message Standards

Enforces Conventional Commits with scope, clear descriptions, and co-authorship attribution.

Test-Driven Development Coach

Enforces red-green-refactor TDD workflow with clear test boundaries and realistic mocking strategies.

API Design First Principles

Guides REST and tRPC API design with consistent naming, error handling, and pagination patterns.

Database Query Optimization

Rules for writing efficient SQL and ORM queries: indexing strategy, N+1 prevention, and query planning.

Python Clean Code Standards

PEP 8 plus pragmatic Python rules: type hints, dataclasses, error handling, and async patterns.

Documentation Writing Standards

Rules for writing clear technical docs: README structure, JSDoc, inline comments, and ADRs.

Conventional Commits Hygiene

Rules for atomic commits with conventional-format messages, criteria for when to split a change, and rebase etiquette for shared branches.

Use when: Use when committing work, cleaning up a branch before review, or deciding how to split a large working-tree diff into commits.

React Component Library AGENTS.md

AGENTS.md for a React component library: composition-first APIs, prop naming rules, required Storybook stories, and accessibility checks that gate every new component.

Use when: Use in a repository that publishes reusable React components so agents design composable prop APIs, write stories alongside components, and treat accessibility failures as build failures.

Modern Python Project Instructions (uv + ruff + pytest)

CLAUDE.md for Python projects managed with uv: dependency rules, ruff lint/format gates, pytest conventions, and a no-untyped-code policy agents can verify.

Use when: Use in any Python 3.12+ project that uses uv for environments and packaging, so agents run the right commands and never reach for pip, poetry, or unformatted code.

Refactor Without Behavior Change

Pin current behavior with characterization tests, then restructure in small always-green steps so the diff provably changes no behavior.

Use when: Use when restructuring, renaming, extracting, or moving existing code where the requirement is that observable behavior stays identical.

Next.js 15 App Router Project Instructions

CLAUDE.md template for Next.js 15 App Router projects: server-component defaults, data-fetching rules, file layout, and the commands an agent should run before committing.

Use when: Drop into the root of a Next.js 15+ project using the App Router so coding agents follow your server/client component boundaries and caching conventions instead of guessing.

FastAPI Project Rules

FastAPI conventions for Pydantic v2 schemas, Depends-based wiring, async discipline, and a predictable router layout.

Use when: Use in FastAPI services with Pydantic v2 to keep routers thin, dependencies explicit, and blocking calls out of the event loop.

Dependency Upgrade Protocol

Upgrade dependencies without surprises: changelogs before commands, one major at a time, lockfile diff review, and smoke tests per step.

Use when: Use when bumping dependencies — routine maintenance, a security advisory, or a major-version migration — rather than running a blanket update command.

pnpm + Turborepo Monorepo Instructions

CLAUDE.md for a pnpm/Turborepo monorepo: package boundary rules, the task pipeline, affected-only builds, and how agents should add dependencies without breaking workspaces.

Use when: Use at the root of a pnpm workspace with Turborepo so agents scope commands to the right package, respect import boundaries, and avoid running the entire pipeline for one-package changes.

Profile Before Optimizing

A measurement-first optimization loop — profile under realistic load, fix exactly one hot spot, re-measure, and keep the numbers in the commit.

Use when: Use when something is slow or resource-hungry and the urge is to start rewriting code that merely looks expensive.

Open Source Maintainer AGENTS.md

AGENTS.md for maintaining an open source library: semver rules, changelog discipline, public API stability checks, deprecation policy, and issue triage labels.

Use when: Use in a published open source package when agents help with releases, PR review, or issue triage, so they protect the public API and follow semver and changelog conventions exactly.

Terraform and IaC Rules for Agents

Guardrails for agents touching Terraform: always plan before apply, module and state layout, what never to do to state files, and mandatory resource tagging.

Use when: Use in any repository containing Terraform when agents write or modify infrastructure code, so changes are planned and reviewed before apply and state is never put at risk.

Database Migration Safety

Ship schema changes without downtime using expand-contract: backwards-compatible steps, safe locking, and a rollback plan written before running anything.

Use when: Use when writing or reviewing a schema migration, especially renames, type changes, NOT NULL additions, or anything touching a large or hot table.

Accessibility Rules for JSX

A11y rules putting semantic HTML before ARIA, with concrete requirements for focus management, labels, and color contrast.

Use when: Attach to TSX files in any React codebase to catch div-button soup, focus traps, and ARIA misuse while components are being written.