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CLAUDE.md

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+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## About OpenMetadata
+
+OpenMetadata is a unified metadata platform for data discovery, data observability, and data governance. This is a multi-module project with Java backend services, React frontend, Python ingestion framework, and comprehensive Docker infrastructure.
+
+## Architecture Overview
+
+- **Backend**: Java 21 + Dropwizard REST API framework, multi-module Maven project
+- **Frontend**: React + TypeScript + Ant Design, built with Webpack and Yarn
+- **Ingestion**: Python 3.9+ with Pydantic 2.x, 75+ data source connectors
+- **Database**: MySQL (default) or PostgreSQL with Flyway migrations
+- **Search**: Elasticsearch 7.17+ or OpenSearch 2.6+ for metadata discovery
+- **Infrastructure**: Apache Airflow for workflow orchestration
+
+## Essential Development Commands
+
+### Prerequisites and Setup
+```bash
+make prerequisites              # Check system requirements
+make install_dev_env           # Install all development dependencies
+make yarn_install_cache        # Install UI dependencies
+```
+
+### Frontend Development
+```bash
+cd openmetadata-ui/src/main/resources/ui
+yarn start                     # Start development server on localhost:3000
+yarn test                      # Run Jest unit tests
+yarn playwright:run            # Run E2E tests
+yarn lint                      # ESLint check
+yarn lint:fix                  # ESLint with auto-fix
+```
+
+### Backend Development
+```bash
+mvn clean package -DskipTests  # Build without tests
+mvn clean package -DonlyBackend -pl !openmetadata-ui  # Backend only
+mvn test                       # Run unit tests
+mvn verify                     # Run integration tests
+mvn spotless:apply             # Format Java code
+```
+
+### Python Ingestion Development
+```bash
+cd ingestion
+make install_dev_env           # Install in development mode
+make generate                  # Generate Pydantic models from JSON schemas
+make unit_ingestion_dev_env    # Run unit tests
+make lint                      # Run pylint
+make py_format                 # Format with black, isort, pycln
+make static-checks             # Run type checking with basedpyright
+```
+
+### Full Local Environment
+```bash
+./docker/run_local_docker.sh -m ui -d mysql        # Complete local setup with UI
+./docker/run_local_docker.sh -m no-ui -d postgresql # Backend only with PostgreSQL
+./docker/run_local_docker.sh -s true               # Skip Maven build step
+```
+
+### Testing
+```bash
+make run_e2e_tests             # Full E2E test suite
+make unit_ingestion            # Python unit tests with coverage
+yarn test:coverage             # Frontend test coverage
+```
+
+## Code Generation and Schemas
+
+OpenMetadata uses a schema-first approach with JSON Schema definitions driving code generation:
+
+```bash
+make generate                  # Generate all models from schemas
+make py_antlr                  # Generate Python ANTLR parsers
+make js_antlr                  # Generate JavaScript ANTLR parsers
+yarn parse-schema              # Parse JSON schemas for frontend
+```
+
+## Key Directories
+
+- `openmetadata-service/` - Core Java backend services and REST APIs
+- `openmetadata-ui/src/main/resources/ui/` - React frontend application
+- `ingestion/` - Python ingestion framework with connectors
+- `openmetadata-spec/` - JSON Schema specifications for all entities
+- `bootstrap/sql/` - Database schema migrations and sample data
+- `conf/` - Configuration files for different environments
+- `docker/` - Docker configurations for local and production deployment
+
+## Development Workflow
+
+1. **Schema Changes**: Modify JSON schemas in `openmetadata-spec/`, then run `mvn clean install` on openmetadata-spec to update models
+2. **Backend**: Develop in Java using Dropwizard patterns, test with `mvn test`  
+3. **Frontend**: Use React/TypeScript with Ant Design components, test with Jest/Playwright
+4. **Ingestion**: Python connectors follow plugin pattern, use `make install_dev_env` for development
+5. **Full Testing**: Use `make run_e2e_tests` before major changes
+
+## Database and Migrations
+
+- Flyway handles schema migrations in `bootstrap/sql/migrations/`
+- Use Docker containers for local database setup
+- Default MySQL, PostgreSQL supported as alternative
+- Sample data loaded automatically in development environment
+
+## Security and Authentication
+
+- JWT-based authentication with OAuth2/SAML support
+- Role-based access control defined in Java entities
+- Security configurations in `conf/openmetadata.yaml`
+- Never commit secrets - use environment variables or secure vaults