# Startup Skills: Engineering

> Every Engineering skill in the index, with a line saying when to use each one.

I index these, I do not host them. Every entry points at the original author's
repo and carries a source byline.

## Entries (98)

- [Browser testing with DevTools](https://github.com/addyosmani/agent-skills/tree/main/skills/browser-testing-with-devtools) by Addy Osmani: Use when a browser bug needs real DOM, console and network data via DevTools.
- [Code review and quality](https://github.com/addyosmani/agent-skills/tree/main/skills/code-review-and-quality) by Addy Osmani: Use when a change is about to enter the main branch unreviewed.
- [Constraint-driven development](https://github.com/addyosmani/agent-skills/tree/main/skills/constraint-driven-development) by Addy Osmani: Use when agents must not quietly lower a project's written quality bar.
- [Core Web Vitals](https://github.com/addyosmani/web-quality-skills/tree/main/skills/core-web-vitals) by Addy Osmani: Use when LCP, INP or CLS scores need improving from field and lab data.
- [Doubt-driven development](https://github.com/addyosmani/agent-skills/tree/main/skills/doubt-driven-development) by Addy Osmani: Use when high-stakes decisions need a fresh-context adversarial review before they stand.
- [Performance](https://github.com/addyosmani/web-quality-skills/tree/main/skills/performance) by Addy Osmani: Use when pages load slowly and the site needs to feel faster.
- [Security and hardening](https://github.com/addyosmani/agent-skills/tree/main/skills/security-and-hardening) by Addy Osmani: Use when code handling untrusted input, sessions or logins needs hardening against vulnerabilities.
- [Source-driven development](https://github.com/addyosmani/agent-skills/tree/main/skills/source-driven-development) by Addy Osmani: Use when an approach should be grounded in official documentation, not remembered patterns.
- [Web quality audit](https://github.com/addyosmani/web-quality-skills/tree/main/skills/web-quality-audit) by Addy Osmani: Use when a site needs one audit across performance, accessibility, SEO and best practices.
- [Recursive code review](https://github.com/angiejones/skills/tree/main/recursive-code-review) by Angie Jones: Use when a diff needs several tightening passes, not one verdict.
- [Repo readiness](https://github.com/angiejones/skills/tree/main/repo-readiness) by Angie Jones: Use when checking whether a repository has the context files coding agents need.
- [antfu](https://github.com/antfu/skills/tree/main/skills/antfu) by Anthony Fu: Use when a JavaScript or TypeScript project should follow Anthony Fu's tooling conventions.
- [Slidev](https://github.com/antfu/skills/tree/main/skills/slidev) by Anthony Fu: Use when a technical talk or code walkthrough needs a Markdown slide deck.
- [Compose component design](https://github.com/chrisbanes/skills/blob/main/skills/compose-component-design/SKILL.md) by Chris Banes: Use when designing or reviewing the API of a reusable Jetpack Compose component.
- [Compose performance](https://github.com/chrisbanes/skills/blob/main/skills/compose-performance/SKILL.md) by Chris Banes: Use when investigating Jetpack Compose recomposition cost, stability reports or unstable parameters.
- [Compose state and effects](https://github.com/chrisbanes/skills/blob/main/skills/compose-state-and-effects/SKILL.md) by Chris Banes: Use when writing or reviewing Jetpack Compose state ownership, hoisting or effects.
- [Implement with subagents](https://github.com/chrisbanes/skills/blob/main/skills/implement-with-subagents/SKILL.md) by Chris Banes: Use when a queue of tickets is being implemented by separate subagents.
- [Kotlin API design](https://github.com/chrisbanes/skills/blob/main/skills/kotlin-api-design/SKILL.md) by Chris Banes: Use when deciding whether Kotlin code is a member, extension, factory or value class.
- [Kotlin concurrency and flow](https://github.com/chrisbanes/skills/blob/main/skills/kotlin-concurrency-and-flow/SKILL.md) by Chris Banes: Use when writing or reviewing Kotlin coroutine scopes, cancellation, StateFlow or SharedFlow.
- [Release Kotlin library](https://github.com/chrisbanes/skills/blob/main/skills/release-kotlin-library/SKILL.md) by Chris Banes: Use when publishing a new Kotlin library version with gradle-maven-publish-plugin.
- [Componentize](https://github.com/howells/skills/blob/main/componentize/SKILL.md) by Daniel Howells: Use when shared UI needs consolidating, files need splitting or packages extracting.
- [Fieldtest](https://github.com/howells/skills/blob/main/fieldtest/SKILL.md) by Daniel Howells: Use when a running web app needs QA in a real browser, with evidence.
- [Improve CLAUDE.md](https://github.com/dexhorthy/slopfiles/tree/main/plugins/improve-claude-md/skills/improve-claude-md) by Dex Horthy: Use when agents keep ignoring instructions in a CLAUDE.md file.
- [Finishing a development branch](https://github.com/obra/superpowers/tree/main/skills/finishing-a-development-branch) by Jesse Vincent: Use when a branch is done, tests pass, and it must be integrated.
- [Receiving code review](https://github.com/obra/superpowers/tree/main/skills/receiving-code-review) by Jesse Vincent: Use when review feedback arrives and needs verifying before any suggestion is implemented.
- [Subagent-driven development](https://github.com/obra/superpowers/tree/main/skills/subagent-driven-development) by Jesse Vincent: Use when a plan's independent tasks should run through subagents in this session.
- [Systematic debugging](https://github.com/obra/superpowers/tree/main/skills/systematic-debugging) by Jesse Vincent: Use when a bug or failing test needs investigating before any fix is proposed.
- [Test-driven development](https://github.com/obra/superpowers/tree/main/skills/test-driven-development) by Jesse Vincent: Use when about to write implementation code for a feature or fix.
- [Using git worktrees](https://github.com/obra/superpowers/tree/main/skills/using-git-worktrees) by Jesse Vincent: Use when feature work needs a workspace isolated from the current one.
- [Verification before completion](https://github.com/obra/superpowers/tree/main/skills/verification-before-completion) by Jesse Vincent: Use when about to claim work is done, fixed or passing.
- [Writing plans](https://github.com/obra/superpowers/tree/main/skills/writing-plans) by Jesse Vincent: Use when a spec exists and the work needs a plan before any code.
- [Writing skills](https://github.com/obra/superpowers/tree/main/skills/writing-skills) by Jesse Vincent: Use when creating, editing or testing a skill before it is deployed.
- [Adversarial code reviewing](https://github.com/lox/agent-skills/blob/main/adversarial-code-reviewing/SKILL.md) by Lachlan Donald: Use when the call is ship or do not ship, and confidence feels untested.
- [Babysitting PRs](https://github.com/lox/agent-skills/blob/main/babysitting-prs/SKILL.md) by Lachlan Donald: Use when a pull request is stuck on CI, rebases or review feedback.
- [Check docs updated](https://github.com/lox/agent-skills/blob/main/check-docs-updated/SKILL.md) by Lachlan Donald: Use when code changed and the docs, runbooks or changelog may now be stale.
- [Drafting plans](https://github.com/lox/agent-skills/blob/main/drafting-plans/SKILL.md) by Lachlan Donald: Use when an architecture or rollout decision needs a short written plan that lasts.
- [Go CLI writing](https://github.com/lox/agent-skills/blob/main/go-cli-writing/SKILL.md) by Lachlan Donald: Use when building or refactoring a Go command-line tool's flags, subcommands or config.
- [Go writing](https://github.com/lox/agent-skills/blob/main/go-writing/SKILL.md) by Lachlan Donald: Use when writing, reviewing or refactoring Go packages, tests or benchmarks.
- [High performance Zig](https://github.com/lox/agent-skills/blob/main/high-performance-zig/SKILL.md) by Lachlan Donald: Use when Zig code is latency, memory or layout sensitive and must be measured.
- [Simplicity review](https://github.com/lox/agent-skills/blob/main/simplicity-review/SKILL.md) by Lachlan Donald: Use when a change looks over-engineered and the code may not need to exist.
- [Writing PR descriptions](https://github.com/lox/agent-skills/blob/main/writing-pr-descriptions/SKILL.md) by Lachlan Donald: Use when a pull request needs a title and body that match its diff.
- [Writing tests](https://github.com/lox/agent-skills/blob/main/writing-tests/SKILL.md) by Lachlan Donald: Use when deciding whether to add tests or changing mocks, snapshots or assertions.
- [Code review](https://github.com/mattpocock/skills/tree/main/skills/engineering/code-review) by Matt Pocock: Use when a branch must be checked against repo standards and the original spec.
- [Codebase design](https://github.com/mattpocock/skills/tree/main/skills/engineering/codebase-design) by Matt Pocock: Use when deciding a module's interface or where a seam should go.
- [Diagnosing bugs](https://github.com/mattpocock/skills/tree/main/skills/engineering/diagnosing-bugs) by Matt Pocock: Use when a hard bug or performance regression needs a diagnosis loop.
- [Domain modeling](https://github.com/mattpocock/skills/tree/main/skills/engineering/domain-modeling) by Matt Pocock: Use when a project's terminology, CONTEXT.md or ADRs need writing or sharpening.
- [Improve codebase architecture](https://github.com/mattpocock/skills/tree/main/skills/engineering/improve-codebase-architecture) by Matt Pocock: Use when scanning a codebase for deepening opportunities, then working through the one picked.
- [Prototype](https://github.com/mattpocock/skills/tree/main/skills/engineering/prototype) by Matt Pocock: Use when a state model or UI idea needs testing before real work starts.
- [TDD](https://github.com/mattpocock/skills/tree/main/skills/engineering/tdd) by Matt Pocock: Use when building a feature or fixing a bug test first, red-green-refactor.
- [To tickets](https://github.com/mattpocock/skills/tree/main/skills/engineering/to-tickets) by Matt Pocock: Use when an agreed plan has to become ordered tickets in a tracker.
- [Triage](https://github.com/mattpocock/skills/tree/main/skills/engineering/triage) by Matt Pocock: Use when incoming issues and outside pull requests are piling up unsorted.
- [Wayfinder](https://github.com/mattpocock/skills/tree/main/skills/engineering/wayfinder) by Matt Pocock: Use when work too big for one agent session needs mapping as decision tickets.
- [Wizard](https://github.com/mattpocock/skills/tree/main/skills/engineering/wizard) by Matt Pocock: Use when only a human can do the steps and needs walking through them.
- [Writing for agents](https://github.com/mattpocock/skills/tree/main/skills/productivity/writing-for-agents) by Matt Pocock: Use when creating skills or editing AGENTS.md or CLAUDE.md files.
- [Code reviewer](https://github.com/elithrar/dotfiles/blob/main/.agents/skills/code-reviewer/SKILL.md) by Matt Silverlock: Use when one specific diff must be read for defects, with no wider audit.
- [Create README](https://github.com/elithrar/dotfiles/blob/main/.agents/skills/create-readme/SKILL.md) by Matt Silverlock: Use when an open source project's README needs writing or rewriting.
- [Prompt engineer](https://github.com/elithrar/dotfiles/blob/main/.agents/skills/prompt-engineer/SKILL.md) by Matt Silverlock: Use when a system prompt or tool description causes over-searching, format drift or conflicts.
- [Web perf](https://github.com/elithrar/dotfiles/blob/main/.agents/skills/web-perf/SKILL.md) by Matt Silverlock: Use when diagnosing slow loads or layout shift from browser traces and network evidence.
- [Fastify best practices](https://github.com/mcollina/skills/blob/main/skills/fastify/SKILL.md) by Matteo Collina: Use when building, configuring or debugging a Fastify server or REST API.
- [Init](https://github.com/mcollina/skills/blob/main/skills/init/SKILL.md) by Matteo Collina: Use when a repository's AGENTS.md is missing, too long, generic or stale.
- [Linting neostandard ESLint 9](https://github.com/mcollina/skills/blob/main/skills/linting-neostandard-eslint9/SKILL.md) by Matteo Collina: Use when ESLint flat config or neostandard needs setting up or migrating.
- [Node](https://github.com/mcollina/skills/blob/main/skills/node/SKILL.md) by Matteo Collina: Use when building Node.js projects in TypeScript, including error handling, streams and testing.
- [Node.js core](https://github.com/mcollina/skills/blob/main/skills/nodejs-core/SKILL.md) by Matteo Collina: Use when contributing to Node.js core or debugging native crashes, addons and libuv.
- [OAuth](https://github.com/mcollina/skills/blob/main/skills/oauth/SKILL.md) by Matteo Collina: Use when securing Fastify routes with OAuth flows, tokens and PKCE.
- [Cloud stacked diffs](https://github.com/dabit3/cloud-stacked-diffs/blob/main/.agents/skills/cloud-stacked-diffs/SKILL.md) by Nader Dabit: Use when a large change should ship as a chain of stacked draft PRs.
- [Better Stimulus](https://github.com/obie/skills/blob/main/skills/better-stimulus/SKILL.md) by Obie Fernandez: Use when writing StimulusJS controllers that need to stay maintainable and reusable.
- [MCP OAuth setup](https://github.com/obie/skills/blob/main/skills/mcp-oauth-setup/SKILL.md) by Obie Fernandez: Use when an admin UI must let users connect third-party MCP servers with credentials.
- [Rails activity timeline](https://github.com/obie/skills/blob/main/skills/rails-activity-timeline/SKILL.md) by Obie Fernandez: Use when a Rails model needs an activity timeline with live Turbo Stream updates.
- [Rails Tiptap autosave](https://github.com/obie/skills/blob/main/skills/rails-tiptap-autosave/SKILL.md) by Obie Fernandez: Use when Rails models need Tiptap rich text editing with debounced autosave.
- [Native app performance](https://github.com/steipete/agent-scripts/tree/main/skills/native-app-performance) by Peter Steinberger: Use when profiling a native app with xctrace and Time Profiler to find hotspots.
- [Oracle](https://github.com/steipete/agent-scripts/tree/main/skills/oracle) by Peter Steinberger: Use when bundled prompts and files need a second model's review.
- [Project structure](https://github.com/steipete/agent-scripts/tree/main/skills/project-structure) by Peter Steinberger: Use when an agent needs one symbol map of a TypeScript or Swift repo.
- [Skill cleaner](https://github.com/steipete/agent-scripts/tree/main/skills/skill-cleaner) by Peter Steinberger: Use when Codex or OpenClaw skills need auditing for budget, usage and duplicates.
- [Cranky Old Sam](https://github.com/ramparte/cranky-old-sam/blob/main/skills/cranky-old-sam/SKILL.md) by Sam Schillace: Use when a design review should question every abstraction and argue for less.
- [Frontend accessibility best practices](https://github.com/sergiodxa/agent-skills/blob/main/skills/frontend-accessibility-best-practices/SKILL.md) by Sergio Xalambri: Use when building or reviewing React components, forms and controls for accessibility.
- [Frontend async best practices](https://github.com/sergiodxa/agent-skills/blob/main/skills/frontend-async-best-practices/SKILL.md) by Sergio Xalambri: Use when async code has request waterfalls that could run in parallel.
- [Frontend internationalization best practices](https://github.com/sergiodxa/agent-skills/blob/main/skills/frontend-internationalization-best-practices/SKILL.md) by Sergio Xalambri: Use when adding locales or language switching to a React Router app with remix-i18next.
- [Frontend React best practices](https://github.com/sergiodxa/agent-skills/blob/main/skills/frontend-react-best-practices/SKILL.md) by Sergio Xalambri: Use when writing or reviewing React components for rendering and bundle performance.
- [Frontend React Router best practices](https://github.com/sergiodxa/agent-skills/blob/main/skills/frontend-react-router-best-practices/SKILL.md) by Sergio Xalambri: Use when writing React Router loaders, actions, forms or routes.
- [Frontend testing best practices](https://github.com/sergiodxa/agent-skills/blob/main/skills/frontend-testing-best-practices/SKILL.md) by Sergio Xalambri: Use when writing frontend tests that favour end-to-end coverage over mocks.
- [OWASP security check](https://github.com/sergiodxa/agent-skills/blob/main/skills/owasp-security-check/SKILL.md) by Sergio Xalambri: Use when checking a web app or REST API against the OWASP Top 10.
- [Migrate Radix to Base](https://github.com/shadcn-ui/ui/blob/main/skills/migrate-radix-to-base/SKILL.md) by shadcn: Use when moving a React or shadcn project from Radix UI to Base UI.
- [shadcn](https://github.com/shadcn-ui/ui/blob/main/skills/shadcn/SKILL.md) by shadcn: Use when adding, fixing or styling shadcn/ui components in a project with components.json.
- [AI engineering](https://github.com/swyxio/skills/tree/main/ai-engineering) by Shawn Wang: Use when a multi-request AI workflow fails on retries, rate limits or malformed output.
- [Align me](https://github.com/swyxio/skills/tree/main/align-me) by Shawn Wang: Use when preferences and ambiguity need settling before a long autonomous run.
- [Claude session introspect](https://github.com/swyxio/skills/tree/main/claude-session-introspect) by Shawn Wang: Use when token counts or compaction details are needed from a Claude Code session.
- [Cloudflare production builder](https://github.com/swyxio/skills/tree/main/cloudflare-production-builder) by Shawn Wang: Use when designing, migrating or deploying a production system on Cloudflare Workers.
- [Data chatbots](https://github.com/swyxio/skills/tree/main/data-chatbots) by Shawn Wang: Use when building a copilot that proposes data changes for a human to approve.
- [Long-Running Operation UX](https://github.com/swyxio/skills/tree/main/long-running-operation-ux) by Shawn Wang: Use when a slow async action needs visible progress, cancellation or result handoff.
- [Resilient computer use](https://github.com/swyxio/skills/tree/main/resilient-computer-use) by Shawn Wang: Use when a multi-step desktop or browser task runs through Computer Use.
- [Skill cutter](https://github.com/swyxio/skills/tree/main/skill-cutter) by Shawn Wang: Use when an existing SKILL.md needs trimming to its core or triggering less often.
- [Slackbot builder](https://github.com/swyxio/skills/tree/main/slackbot-builder) by Shawn Wang: Use when designing or hardening a Slack bot's event handling and interaction architecture.
- [cogapp Markdown](https://github.com/simonw/skills/blob/main/cogapp-markdown/SKILL.md) by Simon Willison: Use when README sections such as CLI help output should be generated from code.
- [uv TDD](https://github.com/simonw/skills/blob/main/uv-tdd/SKILL.md) by Simon Willison: Use when starting a Python project with uv and building it test first.
- [Code contracts](https://github.com/spolu/code-contracts/blob/main/skills/code-contracts/SKILL.md) by Stanislas Polu: Use when defining or enforcing @cc code contracts across a codebase.
- [Layered Rails](https://github.com/palkan/layered-rails-skills/blob/master/layered-rails/skills/layered-rails/SKILL.md) by Vladimir Dementyev: Use when Rails controllers and models have grown fat and layers are blurred.
- [Hono Inertia](https://github.com/yusukebe/skills/blob/main/skills/hono-inertia/SKILL.md) by Yusuke Wada: Use when a Hono and hono/jsx app needs SPA-style interactivity through Inertia.
- [Hono React](https://github.com/yusukebe/skills/blob/main/skills/hono-react/SKILL.md) by Yusuke Wada: Use when a Hono project needs real React for its ecosystem, SSR or SPA.

## Links

- [Page](https://startupskills.dev/engineering): the same list, for a person.
- [The whole index](https://startupskills.dev/llms.txt): all 189 entries.
- [Skills index](https://startupskills.dev/skills): every skill, with search.