Application-level @youneed/server plugins beyond the core middleware — API protocols, background services, and observability. GraphQL (@youneed/server-plugin-graphql: schema-first SDL or GraphQLSchema + resolvers, spec-compliant POST/GET endpoint, GraphiQL, devtools tab), gRPC (@youneed/server-plugin-grpc: @grpc/grpc-js server on its own HTTP/2 listener tied to the app lifecycle, .proto load, call-tester devtools), transactional email (@youneed/server-plugin-mailer: MailTransport contract + SMTP/SES/SendGrid/Postmark transports, no SDKs), object/blob storage (@youneed/server-plugin-storage: StorageAdapter contract + Memory/File/S3 adapters), a durable background job queue (@youneed/server-plugin-queue: retries+backoff, dead-letter, delayed/concurrent workers, persisted to KV), and OTLP trace export (@youneed/server-plugin-otlp: batches trace-middleware spans, POSTs OTLP/HTTP JSON to a collector/Jaeger/Tempo/Grafana, no OTel SDK). Use this skill when adding a GraphQL or gRPC endpoint, sending email, storing fi
Expert assistant for the youneed framework (@youneed/dom web components and @youneed/server HTTP server, both on TC39 decorators). This skill should be used when answering questions about youneed components or server, organizing youneed code, optimizing performance bottlenecks, wiring up or recommending @youneed/server-middleware-* packages, adding authentication or login (OAuth2/OIDC providers, OTP, JWT/API-key verification, webhook signatures), handling file uploads, migrating a frontend from React/Vue/Angular/Lit to @youneed/dom, or migrating a backend from Express/Nest/Fastify/Bun/Elysia/tRPC to @youneed/server.
Building command-line tools with @youneed/cli — a type-safe, Commander-style CLI framework on the @youneed factory-class pattern (commands and options as classes, this.options/execute(...) typed straight from flag strings), plus a reactive render()/task live region, onion middleware (providers), application plugins, and graceful shutdown. Covers the cli-middleware-*/cli-plugin-* ecosystem: terminal UIs (screen, progress, prompt, pages, oscillator, color, markdown), input/process security (env, childprocess, fs, worker, clipboard), startup/redraw optimization (cache, worker, scheduler), and accessibility (NO_COLOR/TTY detection, notification, music, i18n). This skill should be used when defining commands or options, building a terminal UI / TUI, validating CLI input or env, spawning subprocesses safely, prompting interactively, speeding up CLI startup or redraws, or making a CLI screen-reader / non-TTY friendly.
The HTTP boundary of a youneed app — consuming APIs and running the server on any runtime. @youneed/api-client: a typed API-client runtime plus an OpenAPI → TypeScript client codegen (CLI youneed-api-codegen + programmatic generateClient) that consumes the OpenAPI doc @youneed/server emits, so there's no hand-written fetch and no server/client drift; dependency-free (global fetch, or pass @youneed/http-client). @youneed/http-client: a zero-dependency universal resilient fetch wrapper (per-attempt timeout, retry with exponential backoff + full jitter honoring Retry-After and only retrying idempotent methods by default, and a circuit breaker) that works in Node/Bun/Deno/browser. @youneed/server-adapter: run one @youneed/server app on any runtime — a Web fetch(Request)=>Response bridge over the app's node:http listener for edge/serverless (Cloudflare Workers, Vercel/Netlify edge, Lambda) plus node/bun/deno serve adapters with runtime auto-detection. Use this skill when generating or consuming a typed API client,
Developer-experience tooling for the youneed framework: wiring up @youneed/devtools (runtime component inspector — tree, props history/time-travel, emitted events, live scheduler swap, style editing) and @youneed/ts-plugin (TypeScript language-service plugin giving autocomplete, hover docs, go-to-definition and squiggle diagnostics inside html`` and css`` templates). This skill should be used when setting up, configuring, debugging, or explaining the youneed devtools panel or the ts-plugin editor integration.
Feature flags in the youneed framework. The framework-agnostic @youneed/feature-flags engine (boolean/variant/value flags, attribute targeting + deterministic percentage rollout by targetingKey, synchronous evaluation across DOM/SSR/CLI/server, SSR snapshot hydration, onEvaluation hook) plus its per-surface integrations — @youneed/server-plugin-feature-flags (request-scoped this.flags + control/bootstrap routes + devtools), @youneed/dom-provider-feature-flags (evaluate in templates, re-render on change), @youneed/ssr-plugin-feature-flags (server-evaluate + inject snapshot into <head> so the client hydrates identical values), @youneed/cli-plugin-feature-flags (flags command + this.flags in commands), @youneed/test-plugin-feature-flags (fresh engine per test, withFlags/expectFlag) — and remote/source adapters @youneed/feature-flags-vercel (Edge Config source), -launchdarkly (remote evaluator), -posthog (/decide evaluator), -datadog (exposure telemetry sink). Use this skill when defining flags, targeting/rollout
The shared foundation under every @youneed package and the tooling to build on it. @youneed/core — the zero-dependency primitives the whole monorepo builds on: shared type aliases, the class-metadata registry (createRegistry/ctorOf/classChain — the TC39 addInitializer + WeakMap pattern that makes decorators work under esbuild/tsx where Symbol.metadata is never emitted), and disposal helpers (dispose/isDisposable/disposeValue bridging plain cleanups to using/await using). @youneed/vite-plugin — the domFramework() Vite plugin that pre-transpiles TC39 standard decorators with esbuild (supported:{decorators:false}) before Vite's oxc/esbuild transform, which otherwise leaves them raw and breaks the entry graph. create-youneedpackage — the internal scaffolder for new workspace packages. Use this skill when authoring your own decorator-driven base class (Component/Controller/Test-style factory), when standard decorators fail to compile under Vite (blank page / SyntaxError), when adding using-based resource cleanup,
Logging for the youneed framework: the universal @youneed/logger core (createLogger, levels, JSON/format pipeline, secret redaction, child loggers, transport contract), the transport packages (@youneed/logger-transport-stdout, -file, -http), and @youneed/server-plugin-env for fail-fast env loading. This skill should be used when setting up logging, choosing transports, redacting secrets, correlating logs by requestId/traceId on the backend, shipping browser/client logs over HTTP, or wiring log level from config.