Add CLAUDE.md for Claude Code guidance

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.
+
+## Project Overview
+
+This is the OpenShift Cluster Manager (OCM) API model repository, which contains the specification of the OCM API using a custom DSL (Domain Specific Language). The project is structured around three main submodules:
+
+1. **`model/`** - Contains API definitions in `.model` files using a Go-like DSL
+2. **`clientapi/`** - Contains generated Go types and serialization code for the OCM SDK
+3. **`metamodel_generator/`** - Contains tooling to generate code from the model definitions
+
+## Architecture
+
+### Model Language
+The API specification is written using a custom DSL similar to Go, with `.model` files located in service-specific directories:
+- `model/clusters_mgmt/v1/` - Cluster management service definitions
+- `model/accounts_mgmt/v1/` - Account management service definitions  
+- `model/addons_mgmt/v1/` - Add-ons management service definitions
+- `model/aro_hcp/v1alpha1/` - ARO HCP specific definitions
+- And other service directories
+
+### Generated Code Structure
+- **Classes and Structs**: Represent data types (classes have built-in ID/HREF, structs don't)
+- **Resources**: Define API endpoints and collections with methods and locators
+- **Enums**: Define enumerated values
+- **JSON Serialization**: Automatically generated with snake_case conversion
+
+### Class References
+The model supports cross-service references using `@ref` annotations:
+```
+@ref(path = "/clusters_mgmt/v1/cluster")
+class Cluster {
+}
+```
+
+## Common Development Commands
+
+### Core Workflow
+```bash
+# Update generated code (clientapi and openapi) from model changes
+make update
+
+# Verify that generated code matches the model
+make verify
+
+# Check model syntax and structure
+make check
+
+# Clean all generated files
+make clean
+```
+
+### Generation Commands
+```bash
+# Generate only Go client API code
+make clientapi
+
+# Generate only OpenAPI specifications
+make openapi
+
+# Build the metamodel generator binary
+make metamodel
+```
+
+### Linting
+```bash
+# Check model files for proper indentation (tabs only)
+make lint
+```
+
+## Typical Development Workflow
+
+1. **Modify API Model**: Edit `.model` files in the appropriate service directory under `model/`
+2. **Generate Code**: Run `make update` to regenerate `clientapi/` and `openapi/` from model changes
+3. **Verify Changes**: Run `make verify` to ensure generated code matches expectations
+4. **Check Syntax**: Run `make check` to validate model syntax
+
+## Key Files and Directories
+
+- `Makefile` - Contains all build and generation commands
+- `model/` - Source of truth for API definitions
+- `clientapi/` - Generated Go types and builders (submodule)
+- `metamodel_generator/` - Code generation tooling (submodule)
+- `openapi/` - Generated OpenAPI specifications
+- `CHANGES.md` - Change log for API versions
+
+## Model File Conventions
+
+- Use CamelCase for attribute names in model files
+- JSON representation automatically converts to snake_case
+- Classes represent objects with identity (automatic ID/HREF attributes)
+- Structs represent value objects without identity
+- Resources define API collections and endpoints
+- Methods define HTTP operations (List, Get, Add, Delete)
+- Locators define relationships between resources
+
+## Dependencies
+
+The project requires:
+- Go 1.23+ (see `metamodel_generator/go.mod`)
+- `goimports` for Go code formatting
+- `shasum` or `sha256sum` for verification
+
+## Important Notes
+
+- The `clientapi/` directory is generated - never edit files there directly
+- The `openapi/` directory is generated - never edit files there directly  
+- Always run `make verify` after making changes to ensure consistency
+- The metamodel generator creates both Go types and OpenAPI specifications from the same model source