Skill Claude CodeCodex
Use when designing or analyzing a controlled experiment — falsifiable hypothesis, sample size from an MDE, reading significance/CI/power, CUPED, or rescuing tests that won't go significant. NOT recurring metric tracking (that is analytics), NOT north-star/KPI trees (that is kpi-framework), NOT projecting metrics…
Skill Claude CodeCodex
Use when making a web UI conform to WCAG 2.2 Level AA — axe-core or Lighthouse a11y violations, keyboard operability, focus management, ARIA roles/names/live regions, contrast, tap-target size. NOT palette or visual intent (that is design), NOT test-runner setup (that is testing-web), NOT LCP/page-speed (that is…
Skill Claude CodeCodex
Use when running or fixing paid acquisition on Google or Meta — campaign structure (Performance Max, Demand Gen, Search, Advantage+), platform-fit creative, budget/scaling rules, break-even ROAS math, and Consent Mode v2 / CAPI tracking gaps. NOT the page the ad clicks into (that is landing-copy), NOT the channel-mix…
Skill Claude CodeCodex
Use when measuring whether an LLM or agent system actually got better and gating merges on it: golden sets, fixing an inflated LLM-as-judge, scoring RAG (faithfulness, contextual recall) or agent trajectories (tool correctness, completion), or picking an eval framework. NOT building the agent loop, tools or RAG…
Skill Claude CodeCodex
Use when bounding an LLM agent that already runs — scoping its task domain, gating tools to least privilege, defending against prompt injection in untrusted web/email/RAG text, requiring human approval on irreversible actions, capping runtime and cost, or triaging what it already did. NOT building the loop, tools, or…
Skill Claude CodeCodex
Use when a creative goal must become a finished media file: pick and order generative-media models per modality — AI voiceover, image-to-video clips, score — then glue them with ffmpeg (mux, duck, loudnorm, concat). NOT still-image generation/editing (that is replicate-images); NOT code-rendered React compositing…
Skill Claude CodeCodex
Use when instrumenting product or web analytics — GA4/PostHog SDK wiring, event taxonomy, funnels, double-counted events, consent gating, PII scrubbing. NOT charting that data (that is dashboard), NOT choosing which metrics matter (that is kpi-framework), NOT experiment math (that is ab-testing), NOT cookie-policy…
Skill Claude CodeCodex
Use when constitution, spec, plan and tasks all exist and you want them cross-read against each other before any code is written — the rsc-sdd pre-implementation gate. Reports coverage gaps, contradictions, duplication, ambiguity and scope drift; edits nothing. NOT the task breakdown (that is tasks), NOT the coding…
Skill Claude CodeCodex
Use when building, refactoring, or debugging Angular (v20/21+): standalone components, signals, zoneless change detection, @if/@for/@defer control flow, inject() DI, resource()/httpResource(), RxJS interop, NgRx SignalStore, ng CLI. NOT React (that is react), NOT Next.js (that is nextjs), NOT a TypeScript language…
Skill Claude CodeCodex
Build animation and gestures in React Native and Expo with Reanimated worklets on the UI thread — sheets, drawers, screen transitions, swipe, drag, press feedback, haptics. Use when adding gestures to an Expo app, or when motion stutters, janks or drops frames on a real Android or iOS device.
Skill Claude CodeCodex
Build a web animation: whether it should animate at all, the purpose, the tool, the properties, the easing curve, the duration, interruption and exit. Writes the CSS or Motion code for dropdowns, modals, toasts, tooltips, accordions, press feedback, stagger and scroll reveals. Use to animate something or make a…
Skill Claude CodeCodex
Reverse glossary: turn a vague description of a motion effect into its exact name — a popover growing from its trigger is origin-aware, iOS overscroll is rubber-banding, items appearing one after another with a delay is a stagger. Use for "what's it called when…" or "what do you call it when…".
Skill Claude CodeCodex
Use when writing a client for someone else's REST or GraphQL API: auth flow choice and token refresh, pagination to exhaustion, retry-with-jitter on transient failures only, rate-limit-aware throttling. NOT inbound callbacks (that is webhooks), NOT chaining services (that is automation-flows), NOT designing your own…
Skill Claude CodeCodex
Use when settling the contract of an API you expose, before implementation: resources/URLs, REST vs GraphQL, versioning, one RFC 9457 error envelope, pagination, idempotency — emitted as OpenAPI 3.1. NOT implementing the endpoints (that is fastapi/nestjs/go/nodejs), NOT auth hardening (that is secure-coding), NOT…
Skill Claude CodeCodex
Apple's fluid-interface craft on the web: spring damping and response, velocity handoff, momentum projection on a flick, rubber-banding at a boundary, interruptible motion the user can grab mid-flight, translucent materials and backdrop blur, letter-spacing and leading by size. Use for iOS-grade feel, sheets and drag.
Skill Claude CodeCodex
Use when writing one long-form article end to end — answer-first lede, question-shaped headings, plus its on-page surface (title, meta, slug, FAQ, Article/FAQPage JSON-LD) — or fixing a draft that buries the answer or reads AI-padded. NOT keyword research or topic selection (that is seo-geo), NOT the editorial…
Skill Claude CodeCodex
Sonner, the React toast library: mounting Toaster once, toast() calls, promise and loading toasts, updating, dismissing, styling, theming, dark mode, positioning. Use when toasts do not appear, appear twice, sit behind a modal, ignore Tailwind classes, or do nothing from a server action.
Skill Claude CodeCodex
Use when building a content-driven or marketing site with Astro 6: static-first pages, islands and partial hydration, content collections, server islands, per-route on-demand rendering, deploy adapters, and Astro 5→6 migration. NOT app-router React with server actions and heavy client interactivity (that is nextjs).
Skill Claude CodeCodex
Use when authoring a NEW rsc skill or editing an existing one — scoping it to one job, writing the description that decides whether it ever loads, splitting the body into references/, writing its evals, auditing it against the rubric. NOT building a product feature (that is specify) and NOT designing an agent loop…
Skill Claude CodeCodex
Use when building or fixing a no-code automation on n8n, Make, or Zapier — trigger to multi-app steps with data mapping, dedup, retries and an error path — or picking the platform by billing unit (task vs credit vs execution). NOT a typed API client in code (that is api-connector-builder), NOT a webhook receiver in…
Skill Claude CodeCodex
Use when deciding whether a process is worth automating, sizing ROI and build-vs-buy, choosing an automation platform, or diagnosing why a fleet of automations keeps breaking — the decision layer before anyone builds. NOT building the flow (that is automation-flows, or n8n / make / zapier / power-automate to drive a…
Skill Claude CodeCodex
Use when standing up the core AWS surface a small product needs: hardening a fresh account, a private S3 bucket, encrypted RDS Postgres, ECS Fargate vs EC2, CloudFront + OAC, or scoping an IAM policy to least privilege. NOT the CI pipeline that ships the container (that is deployment), NOT app-code access-control…
Skill Claude CodeCodex
Use when designing or auditing a backup-and-restore program that must survive a real disaster: setting defensible RPO/RTO targets, laying out 3-2-1-1-0 copies that are offsite and immutable, wiring point-in-time recovery, and proving restores work on a schedule. NOT tuning Postgres internals or writing the…
Skill Claude CodeCodex
Use when writing or hardening a shell script that must survive another machine — a CI step, install script, cron job, git hook, devcontainer entrypoint: strict-mode leaks, quoting/word-splitting, arrays, trap cleanup, bash-vs-POSIX portability, ShellCheck findings. NOT CI workflow structure, runners, caching or matrix…