diff --git a/.claude/skills/writing-client-code/SKILL.md b/.claude/skills/writing-client-code/SKILL.md
new file mode 100644
index 000000000000..f344cfd4ef0b
--- /dev/null
+++ b/.claude/skills/writing-client-code/SKILL.md
@@ -0,0 +1,105 @@
+---
+name: writing-client-code
+description: Bitwarden client code conventions for Angular and TypeScript. Use when creating components, services, or modifying web/browser/desktop apps.
+---
+
+### Why `libs/common` cannot import Angular
+
+CLI is a first-class client. Any code in `libs/common` must work without Angular's dependency injection, decorators, or lifecycle hooks. This is why cross-client services use abstract classes as interfaces — the concrete implementations (`Default*`, `Web*`, `Browser*`, `Desktop*`, `Cli*`) live in their respective apps.
+
+## Architectural Rationale
+
+### Thin components
+
+Components contain only view logic. Business logic belongs in services. This keeps components testable, reusable, and prevents Angular lifecycle coupling from leaking into domain logic.
+
+### Composition over inheritance
+
+Avoid extending components across clients. Compose using shared child components instead. Inheritance creates tight coupling between client-specific UI and shared behavior — when one client's needs diverge, inherited components become hard to change safely.
+
+### Don't modernize existing code unless asked
+
+The codebase contains both legacy and modern Angular patterns. When modifying an existing file, **follow the patterns already in that file**. Don't migrate any of these unless explicitly asked:
+
+- `*ngIf` → `@if`, `*ngFor` → `@for`
+- `@Input()` / `@Output()` → `input()` / `output()` signals
+- Constructor injection → `inject()`
+- Default change detection → `OnPush`
+- NgModule declarations → standalone components
+
+If asked to modernize, follow this order (per the Angular migration guide): standalone → control flow → input/output signals → view queries → signals → computed → OnPush (last, only after full signal migration).
+
+### State management: Signals vs RxJS
+
+- **Component local state and Angular-only services:** Use Signals
+- **Cross-client services (`libs/common`):** Use RxJS (because CLI has no Angular Signals support)
+
+Avoid manual subscriptions. Prefer `| async` pipe. When subscriptions are necessary, pipe through `takeUntilDestroyed()` — enforced by the `prefer-takeUntil` lint rule.
+
+### No TypeScript enums (ADR-0025)
+
+Use frozen const objects with `Object.freeze()` and `as const`, plus a companion type alias. Enums have runtime behavior that creates subtle bugs with tree-shaking.
+
+## Critical Rules for New Code
+
+These rules apply **strictly to new files and components**. For existing code, follow the patterns already in the file.
+
+- **New components must use `ChangeDetectionStrategy.OnPush`** and be `standalone: true`. `NgModules` are permitted only for grouping related standalone components
+- **Prefer `inject()` function** for DI in Angular primitives (components, pipes, directives). Use constructor injection for code shared with non-Angular clients (CLI)
+- **New templates must use control flow syntax** (`@if`, `@for`, `@switch`), not structural directives
+- **Use `host` property** in component decorators, not `@HostBinding` / `@HostListener`
+- **Use Reactive Forms exclusively** — not template-driven forms
+- **File naming:** `kebab-case.component.ts`, `.service.ts`, `.pipe.ts`, `.directive.ts`. Also: `.request.ts`, `.response.ts`, `.view.ts`, `.data.ts` for models (ADR-0012)
+- **All Tailwind classes require `tw-` prefix** — `tw-flex`, `tw-mt-2`, not `flex`, `mt-2`
+- **Testing with Jest** — use `jest-mock-extended` for mocking services. `describe`/`it` blocks, not `test()`
+- **Imports from `@bitwarden/common`** must not pull in Angular-specific code (breaks CLI)
+
+## Examples
+
+### Dependency injection (new Angular code)
+
+```typescript
+// CORRECT — inject() for Angular primitives
+export class VaultComponent {
+  private vaultService = inject(VaultService);
+}
+
+// ALSO CORRECT — constructor injection for code shared with CLI
+export class CryptoService {
+  constructor(private stateService: StateService) {}
+}
+```
+
+### Tailwind prefix
+
+```html
+<!-- CORRECT -->
+<div class="tw-flex tw-gap-2 tw-mt-4">
+  <!-- WRONG — missing tw- prefix, will be stripped -->
+  <div class="flex gap-2 mt-4"></div>
+</div>
+```
+
+### Const objects over enums (ADR-0025)
+
+```typescript
+// CORRECT — with companion type alias
+export const CipherType = Object.freeze({
+  Login: 1,
+  SecureNote: 2,
+} as const);
+export type CipherType = (typeof CipherType)[keyof typeof CipherType];
+
+// WRONG — TypeScript enums have runtime side effects
+export enum CipherType {
+  Login = 1,
+  SecureNote = 2,
+}
+```
+
+## Further Reading
+
+- [Angular conventions](https://contributing.bitwarden.com/contributing/code-style/web/angular)
+- [Angular migration guide](https://contributing.bitwarden.com/contributing/code-style/web/angular-migration-guide)
+- [TypeScript style](https://contributing.bitwarden.com/contributing/code-style/typescript/)
+- [Component Library](https://contributing.bitwarden.com/contributing/ui/component-library/)