Development

Next.js App Router principles. Server Components, data fetching, routing patterns.

NestJS best practices — 40 rules across modules, DI, error handling, security, performance, testing, database, API design, microservices, and deployment. Use when writing, reviewing, or refactoring NestJS code.

Create software diagrams in Mermaid — class, sequence, flowchart, ERD, C4, state, gitgraph, gantt. Use to "diagram", "visualize", "map out", or "show the flow" of architecture, database schemas, code structure, or user/app flows.

Use when the user wants to design, redesign, shape, critique, audit, polish, clarify, distill, harden, optimize, adapt, animate, colorize, extract, or otherwise improve a frontend interface. Covers websites, landing pages, dashboards, product UI, app shells, components, forms, settings, onboarding, and empty states

Hunting playbook for race-condition / TOCTOU vulnerabilities — concurrent-request abuse, HTTP/2 single-packet attacks, double-redeem / double-spend, MFA-OTP & email-verify races, rate-limit bypass. Use when hunting races or TOCTOU bugs.

Interview the user relentlessly about a plan or design until reaching shared understanding, resolving each branch of the decision tree. Use when user wants to stress-test a plan, get grilled on their design, or mentions "grill me".

Continuous fullstack delivery loop — cycles a combined frontend+backend team through test → diagnose → fix → review → secure → re-test, building both layers together in cross-side vertical-slice waves until every E2E/suite, code-quality, visual-fidelity, and security gate is clean. Use to develop, fix, harden, or finish a feature that spans the API and the UI in one coordinated loop, instead of running the frontend and backend loops back-to-back.

Front-end system-design reference — box model, rendering/reflow, DOM & Web APIs, virtualisation, state design, network transports, web performance.

Continuous frontend delivery loop — cycles subagents through test → diagnose → fix → review → re-test until E2E and review are clean. Use to develop, fix, harden, or finish a frontend feature/epic verified by tests.

Create or update Figma Code Connect template files (.figma.ts/.figma.js) that map Figma components to code. Use for Code Connect, Figma component mapping, design-to-code.

Develop, configure, and debug Fastify (Node.js/TypeScript) servers and REST APIs — routes, plugins, JSON Schema validation, hooks, auth, serialization, performance, deployment. Triggers: Fastify, server.ts, app.ts, fastify.config.

Disciplined diagnosis loop for hard bugs and performance regressions — reproduce → hypothesise → instrument → fix → regression-test. Use when asked to diagnose/debug, something is broken or failing, or a perf regression is reported.

Write a structured retrospective of a delivery-loop run (frontend-delivery-loop, backend-delivery-loop, or fullstack-delivery-loop) that judges what went well, what went badly, where time/roundtrips/tool calls were wasted and in which skill or agent, how the agents integrated, and the session id + trace file paths — then save it as a Markdown report for skill-evolution-factory to act on. Use this the moment a delivery loop finishes (or stalls), whenever the user says "retro", "post-mortem", "...

Explains Cypress tests (E2E and component) and how Cypress works — use to understand, review, or critique tests without editing code, even if the user only says "tests". For creating or fixing tests, prefer cypress-author.

Search and extract Cypress information from official documentation (docs.cypress.io, cypress.io); prefer LLM markdown under /llm/* and refuse unverified API or behavior claims.

Creates, updates, and fixes Cypress tests (E2E and component) — use to write, add, update, or fix failing/flaky tests, even if the user only says "tests". For explaining or reviewing without edits, prefer cypress-explain.

Organize CSS using BEM, SMACSS, and CSS-in-JS patterns. Use when building scalable, maintainable styling systems with proper naming conventions.

Create professional SVG logos, brand identities, icons, wordmarks, and visual marks — multiple concepts, layouts, and color variations. Use when asked to design a logo, brand identity, icon, or visual mark.

Core Web Vitals reference for measuring, diagnosing, and improving LCP, INP, and CLS page performance against Google's thresholds

Write and apply Conventional Commits — type(scope): subject, imperative mood, with body and BREAKING CHANGE footer when needed. Use when committing staged work or asked to write, review, or standardize a commit message.

React composition patterns that scale — compound components, render props, context providers, lifting state. Use when refactoring boolean-prop-heavy components or designing flexible, reusable component APIs (incl. React 19)

The bar for any code you write, edit, or review. Read these rules whenever you are writing or reading any code

Create beautiful visual art in .png and .pdf documents using design philosophy. Use when the user asks to create a poster, piece of art, design, or other static visual piece.

BullMQ Redis-backed job queues in Node.js/TypeScript — workers, delayed/repeatable jobs, flows, rate limiting, retries. Use for background jobs, job scheduling, or reliable async processing.