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CONTRIBUTING.md

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+# Contributing
+
+## Build from Source
+
+> Prerequisites
+> 
+> * Go 1.20 or higher
+> * Git
+> * Make (optional, for simplified builds)
+
+1. **Clone the repository:**
+   ```bash
+   git clone https://github.com/wso2/open-mcp-auth-proxy
+   cd open-mcp-auth-proxy
+   ```
+
+2. **Install dependencies:**
+   ```bash
+   go get -v -t -d ./...
+   ```
+
+3. **Build the application:**
+
+   **Option A: Using Make**
+
+   ```bash
+   # Build for all platforms
+   make all
+   
+   # Or build for specific platforms
+   make build-linux      # For Linux (x86_64)
+   make build-linux-arm  # For ARM-based Linux
+   make build-darwin     # For macOS
+   make build-windows    # For Windows
+   ```
+
+   **Option B: Manual build (works on all platforms)**
+
+   ```bash
+   # Build for your current platform
+   go build -o openmcpauthproxy ./cmd/proxy
+   
+   # Cross-compile for other platforms
+   GOOS=linux GOARCH=amd64 go build -o openmcpauthproxy-linux ./cmd/proxy
+   GOOS=windows GOARCH=amd64 go build -o openmcpauthproxy.exe ./cmd/proxy
+   GOOS=darwin GOARCH=amd64 go build -o openmcpauthproxy-macos ./cmd/proxy
+   ```
+
+After building, you'll find the executables in the `build` directory (when using Make) or in your project root (when building manually).
+
+### Additional Make Targets
+
+If you're using Make, these additional targets are available:
+
+```bash
+make test       # Run tests
+make coverage   # Run tests with coverage report
+make fmt        # Format code with gofmt
+make vet        # Run go vet
+make clean      # Clean build artifacts
+make help       # Show all available targets
+```