Build signal-based forms in Angular v21+ using the new Signal Forms API. Use for form creation with automatic two-way binding, schema-based validation, field state management, and dynamic forms. Triggers on form implementation, adding validation, creating multi-step forms, or building forms with conditional fields. Signal Forms are experimental but recommended for new Angular projects. Don't use for template-driven forms without signals or third-party form libraries like Formly or ngx-formly.
Write unit and integration tests for Angular v20+ applications using Vitest or Jasmine with TestBed and modern testing patterns. Use for testing components with signals, OnPush change detection, services with inject(), and HTTP interactions. Triggers on test creation, testing signal-based components, mocking dependencies, or setting up test infrastructure. Don't use for E2E testing with Cypress or Playwright, or for testing non-Angular JavaScript/TypeScript code.
Use Angular CLI and development tools effectively in Angular v20+ projects. Use for project setup, code generation, building, testing, and configuration. Triggers on creating new projects, generating components/services/modules, configuring builds, running tests, or optimizing production builds. Don't use for Nx workspace commands, custom Webpack configurations, or non-Angular CLI build systems like Vite standalone or esbuild direct usage.