diff --git a/CLAUDE.md b/CLAUDE.md
index db0252ad8c..d07bd3f3e1 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -2,38 +2,30 @@
 
 ## Critical Rules
 
-- **NEVER** edit: `/bin/`, `/obj/`, `/.git/`, `/.vs/`, `/packages/`, generated migration files
-- **Security First**: All code changes must prioritize cryptographic integrity and data protection
-- **Test Coverage**: New features require xUnit unit tests with NSubstitute mocking
-- **Check CODEOWNERS requirements**: The repo has a `.github/CODEOWNERS` file to define team ownership for different parts of the codebase. Respect that code owners have final authority over their designated areas
+- **NEVER** edit: `/bin/`, `/obj/`, `/.git/`, `/.vs/`, `/packages/` which are generated files
+- **NEVER** use code regions: If complexity suggests regions, refactor for better readability
+- **NEVER** compromise zero-knowledge principles: User vault data must remain encrypted and inaccessible to Bitwarden
+- **NEVER** log or expose sensitive data: No PII, passwords, keys, or vault data in logs or error messages
+- **ALWAYS** use secure communication channels: Enforce confidentiality, integrity, and authenticity
+- **ALWAYS** encrypt sensitive data: All vault data must be encrypted at rest, in transit, and in use
+- **ALWAYS** prioritize cryptographic integrity and data protection
+- **ALWAYS** add unit tests (with mocking) for any new feature development
 
 ## Project Context
 
-**Architecture**: CQRS pattern with feature-based organization
-**Framework**: .NET 8.0, ASP.NET Core
-**Database**: SQL Server primary, EF Core supports PostgreSQL, MySQL/MariaDB, SQLite
-**Testing**: xUnit, NSubstitute
-**Container**: Docker, Docker Compose, Kubernetes/Helm deployable
+- **Architecture**: Feature and team-based organization
+- **Framework**: .NET 8.0, ASP.NET Core
+- **Database**: SQL Server primary, EF Core supports PostgreSQL, MySQL/MariaDB, SQLite
+- **Testing**: xUnit, NSubstitute
+- **Container**: Docker, Docker Compose, Kubernetes/Helm deployable
 
-## Development Standards
+## Project Structure
 
-### CQRS Pattern
-
-- Commands: `/src/Core/[Feature]/Commands/`
-- Queries: `/src/Core/[Feature]/Queries/`
-- Handlers implement `ICommandHandler<T>` or `IQueryHandler<T>`
-
-### API Conventions
-
-- RESTful endpoints with standard HTTP status codes
-- Consistent error response: `{ "error": { "message": "..." } }`
-- Pagination: `?skip=0&take=25`
-- API versioning: `/api/v1/`
-
-### Database Migrations
-
-- **SQL Server**: Manual scripts in `/util/Migrator/DbScripts/`
-- **Other DBs**: EF Core migrations via `pwsh ef_migrate.ps1`
+- **Source Code**: `/src/` - Services and core infrastructure
+- **Tests**: `/test/` - Test logic aligning with the source structure, albeit with a `.Test` suffix
+- **Utilities**: `/util/` - Migration tools, seeders, and setup scripts
+- **Dev Tools**: `/dev/` - Local development helpers
+- **Configuration**: `appsettings.{Environment}.json`, `/dev/secrets.json` for local development
 
 ## Security Requirements
 
@@ -42,20 +34,39 @@
 - **Validation**: Input sanitization, parameterized queries, rate limiting
 - **Logging**: Structured logs, no PII/sensitive data in logs
 
+## Common Commands
+
+- **Build**: `dotnet build`
+- **Test**: `dotnet test`
+- **Run locally**: `dotnet run --project src/Api`
+- **Database update**: `pwsh dev/migrate.ps1`
+- **Generate OpenAPI**: `pwsh dev/generate_openapi_files.ps1`
+
 ## Code Review Checklist
 
 - Security impact assessed
-- xUnit tests added/updated
+- xUnit tests added / updated
 - Performance impact considered
 - Error handling implemented
 - Breaking changes documented
 - CI passes: build, test, lint
+- Feature flags considered for new features
+- CODEOWNERS file respected
+
+### Key Architectural Decisions
+
+- Use .NET nullable reference types (ADR 0024)
+- TryAdd dependency injection pattern (ADR 0026)
+- Authorization patterns (ADR 0022)
+- OpenTelemetry for observability (ADR 0020)
+- Log to standard output (ADR 0021)
 
 ## References
 
-- [Architecture](https://contributing.bitwarden.com/architecture/server/)
-- [Contributing Guidelines](https://contributing.bitwarden.com/contributing/)
-- [Setup Guide](https://contributing.bitwarden.com/getting-started/server/guide/)
-- [Code Style](https://contributing.bitwarden.com/contributing/code-style/)
+- [Server architecture](https://contributing.bitwarden.com/architecture/server/)
+- [Architectural Decision Records (ADRs)](https://contributing.bitwarden.com/architecture/adr/)
+- [Contributing guidelines](https://contributing.bitwarden.com/contributing/)
+- [Setup guide](https://contributing.bitwarden.com/getting-started/server/guide/)
+- [Code style](https://contributing.bitwarden.com/contributing/code-style/)
 - [Bitwarden security whitepaper](https://bitwarden.com/help/bitwarden-security-white-paper/)
 - [Bitwarden security definitions](https://contributing.bitwarden.com/architecture/security/definitions)