Agent-to-Agent Protocol SDK Patterns

Purpose: Provide installation, configuration, and usage patterns for A2A Protocol SDKs across multiple programming languages.

Activation Triggers:

• SDK installation requests
• Language-specific A2A setup
• Authentication configuration
• Package dependency issues
• SDK version compatibility
• Import/setup errors

Supported Languages:

• Python (3.8+)
• TypeScript/JavaScript (Node 18+)
• Java (11+)
• C# (.NET 6+)
• Go (1.20+)

Quick Start by Language

Python

# Install SDK
./scripts/install-python.sh

# Verify installation
./scripts/validate-python.sh

TypeScript

# Install SDK
./scripts/install-typescript.sh

# Verify installation
./scripts/validate-typescript.sh

Java

# Install SDK
./scripts/install-java.sh

# Verify installation
./scripts/validate-java.sh

C#

# Install SDK
./scripts/install-csharp.sh

# Verify installation
./scripts/validate-csharp.sh

Go

# Install SDK
./scripts/install-go.sh

# Verify installation
./scripts/validate-go.sh

Installation Scripts

All installation scripts are in scripts/ directory:

• install-python.sh - Install Python SDK via pip
• install-typescript.sh - Install TypeScript SDK via npm/yarn
• install-java.sh - Install Java SDK via Maven/Gradle
• install-csharp.sh - Install C# SDK via NuGet
• install-go.sh - Install Go SDK via go get

Validation scripts verify installation and dependencies:

• validate-python.sh - Check Python SDK installation
• validate-typescript.sh - Check TypeScript SDK installation
• validate-java.sh - Check Java SDK installation
• validate-csharp.sh - Check C# SDK installation
• validate-go.sh - Check Go SDK installation

Configuration Templates

Templates are in templates/ directory:

Environment Setup:

• env-template.txt - Environment variable template (all languages)
• python-config.py - Python configuration example
• typescript-config.ts - TypeScript configuration example
• java-config.xml - Java Maven configuration
• csharp-config.csproj - C# project configuration
• go-mod.txt - Go module configuration

Authentication:

• auth-api-key-template.txt - API key authentication
• auth-oauth-template.txt - OAuth authentication
• auth-jwt-template.txt - JWT authentication

Common Setup Patterns

Environment Variables

All SDKs use environment variables for configuration:

# Required
A2A_API_KEY=your_api_key_here
A2A_BASE_URL=https://api.a2a.example.com

# Optional
A2A_TIMEOUT=30
A2A_RETRY_ATTEMPTS=3
A2A_LOG_LEVEL=info

CRITICAL: Always use placeholders in committed files. Create .env.example with placeholder values only.

Authentication Setup

All SDKs support three authentication methods:

1. API Key - Simplest, for server-to-server
2. OAuth 2.0 - For user-delegated access
3. JWT - For service-to-service with custom claims

See templates/auth-*-template.txt for implementation patterns.

Error Handling

All SDKs provide consistent error handling:

• A2AConnectionError - Network/connectivity issues
• A2AAuthenticationError - Invalid credentials
• A2ARateLimitError - Rate limit exceeded
• A2AValidationError - Invalid request data

See examples/error-handling-*.md for language-specific patterns.

Language-Specific Considerations

Python

• Requires Python 3.8+
• Install via pip: pip install a2a-protocol
• Async support via asyncio
• Type hints available
• See examples/python-basic.py

TypeScript

• Requires Node 18+
• Install via npm: npm install @a2a/protocol
• Full TypeScript definitions included
• Promise-based async/await
• See examples/typescript-basic.ts

Java

• Requires Java 11+
• Maven: Add to pom.xml
• Gradle: Add to build.gradle
• Thread-safe client
• See examples/java-basic.java

C#

• Requires .NET 6+
• NuGet: dotnet add package A2A.Protocol
• Async/await support
• Dependency injection ready
• See examples/csharp-basic.cs

Go

• Requires Go 1.20+
• Install: go get github.com/a2a/protocol-go
• Context-aware operations
• Goroutine-safe
• See examples/go-basic.go

Troubleshooting

Installation Issues

Package not found:

# Python
pip install --upgrade pip
pip install a2a-protocol

# TypeScript
npm cache clean --force
npm install @a2a/protocol

# Java
mvn clean install -U

# C#
dotnet restore --force

# Go
go clean -modcache
go get -u github.com/a2a/protocol-go

Version conflicts: Run the appropriate validation script to check dependencies:

./scripts/validate-<language>.sh

Authentication Errors

1. Check environment variables are set
2. Verify API key format (no extra spaces/newlines)
3. Ensure base URL is correct
4. Check API key permissions

Connection Issues

1. Verify network connectivity
2. Check firewall/proxy settings
3. Validate base URL is accessible
4. Review timeout settings

Security Best Practices

Environment Variables:

• NEVER commit actual API keys
• Use .env files (add to .gitignore)
• Create .env.example with placeholders
• Use secret management in production (Vault, AWS Secrets Manager, etc.)

API Keys:

• Rotate keys regularly
• Use different keys for dev/staging/prod
• Implement key expiration
• Monitor key usage

Network Security:

• Always use HTTPS
• Validate SSL certificates
• Implement request signing for sensitive operations
• Use VPN/private networks for production

Examples

Complete examples for each language:

• examples/python-basic.py - Basic Python usage
• examples/python-async.py - Async Python usage
• examples/typescript-basic.ts - Basic TypeScript usage
• examples/java-basic.java - Basic Java usage
• examples/csharp-basic.cs - Basic C# usage
• examples/go-basic.go - Basic Go usage
• examples/error-handling-python.md - Python error handling
• examples/error-handling-typescript.md - TypeScript error handling
• examples/error-handling-java.md - Java error handling

Resources

Official Documentation:

• Python SDK: https://docs.a2a-protocol.org/python
• TypeScript SDK: https://docs.a2a-protocol.org/typescript
• Java SDK: https://docs.a2a-protocol.org/java
• C# SDK: https://docs.a2a-protocol.org/csharp
• Go SDK: https://docs.a2a-protocol.org/go

GitHub Repositories:

• Python: https://github.com/a2a/protocol-python
• TypeScript: https://github.com/a2a/protocol-ts
• Java: https://github.com/a2a/protocol-java
• C#: https://github.com/a2a/protocol-dotnet
• Go: https://github.com/a2a/protocol-go

Version: 1.0.0 Protocol Compatibility: A2A Protocol 1.0+