A2A Server Configuration

Provides complete patterns and templates for configuring Agent-to-Agent (A2A) servers with different transport mechanisms (HTTP, STDIO, SSE, WebSocket) following MCP (Model Context Protocol) standards.

Security: API Key Handling

CRITICAL: When generating any configuration files or code:

NEVER hardcode actual API keys or secrets

NEVER include real credentials in examples

NEVER commit sensitive values to git

ALWAYS use placeholders: your_service_key_here

ALWAYS create .env.example with placeholders only

ALWAYS add .env* to .gitignore (except .env.example )

ALWAYS read from environment variables in code

ALWAYS document where to obtain keys

Placeholder format: {service}_{env}_your_key_here

Instructions

Phase 1: Analyze Requirements

Determine server configuration needs:

Transport Type

• HTTP: Remote access, REST-like communication, CORS support

• STDIO: Local process communication, pipe-based I/O

• SSE (Server-Sent Events): Real-time streaming, one-way server push

• WebSocket: Bidirectional real-time communication

Framework Detection

• Python: FastAPI, Flask, Starlette

• TypeScript: Express, Fastify, Node.js native http

• Detect from package.json or requirements.txt

Configuration Needs

• Port and host settings

• CORS configuration

• Authentication requirements

• Environment variables

Phase 2: Select and Load Templates

Based on requirements, use templates from templates/ :

Python Templates:

• templates/python-http-server.py

• FastAPI HTTP server

• templates/python-stdio-server.py

• STDIO transport

• templates/python-sse-server.py

• SSE streaming

• templates/python-websocket-server.py

• WebSocket bidirectional

TypeScript Templates:

• templates/typescript-http-server.ts

• Express HTTP server

• templates/typescript-stdio-server.ts

• STDIO transport

• templates/typescript-sse-server.ts

• SSE streaming

• templates/typescript-websocket-server.ts

• WebSocket bidirectional

Phase 3: Configure Transport

Apply configuration based on transport type:

HTTP Configuration:

Python (FastAPI)

if name == "main": import uvicorn uvicorn.run( "main:app", host="0.0.0.0", port=8000, reload=True )

// TypeScript (Express) const PORT = process.env.PORT || 8000; app.listen(PORT, () => { console.log(Server running on port ${PORT}); });

STDIO Configuration:

Python

mcp.run(transport="stdio")

// TypeScript server.connect(new StdioServerTransport());

SSE Configuration:

Python

@app.get("/events") async def events(): return EventSourceResponse(event_generator())

WebSocket Configuration:

Python

@app.websocket("/ws") async def websocket_endpoint(websocket: WebSocket): await websocket.accept()

Phase 4: Add CORS and Security

For HTTP/SSE/WebSocket servers:

Python

from fastapi.middleware.cors import CORSMiddleware

app.add_middleware( CORSMiddleware, allow_origins=[""], # Configure appropriately allow_credentials=True, allow_methods=[""], allow_headers=["*"], )

// TypeScript import cors from 'cors'; app.use(cors({ origin: process.env.ALLOWED_ORIGINS?.split(',') || '*', credentials: true }));

Phase 5: Environment Configuration

Create .env.example with placeholders:

Server Configuration

PORT=8000 HOST=0.0.0.0 ALLOWED_ORIGINS=http://localhost:3000,http://localhost:5173

API Keys (NEVER commit real values)

ANTHROPIC_API_KEY=your_anthropic_key_here OPENAI_API_KEY=your_openai_key_here

Transport Settings

TRANSPORT_TYPE=http ENABLE_CORS=true

Phase 6: Validation

Run validation script:

bash scripts/validate-config.sh <server-file>

Checks:

• No hardcoded API keys

• Environment variable usage

• CORS configuration

• Transport setup validity

• .gitignore includes .env files

Scripts

• scripts/validate-config.sh

• Validate server configuration

• scripts/generate-server.sh

• Generate server from template

• scripts/test-transport.sh

• Test transport connectivity

Templates

Python:

• templates/python-http-server.py

• HTTP server with FastAPI

• templates/python-stdio-server.py

• STDIO transport

• templates/python-sse-server.py

• SSE streaming server

• templates/python-websocket-server.py

• WebSocket server

TypeScript:

• templates/typescript-http-server.ts

• HTTP server with Express

• templates/typescript-stdio-server.ts

• STDIO transport

• templates/typescript-sse-server.ts

• SSE streaming server

• templates/typescript-websocket-server.ts

• WebSocket server

Examples

• examples/http-fastapi-example.md

• Complete HTTP server with FastAPI

• examples/stdio-simple-example.md

• Basic STDIO server

• examples/sse-streaming-example.md

• SSE streaming configuration

• examples/websocket-bidirectional-example.md

• WebSocket bidirectional communication

Requirements

• Framework-specific dependencies (FastAPI/Express/etc.)

• CORS middleware for HTTP/SSE/WebSocket

• Environment variable management (python-dotenv/dotenv)

• No hardcoded API keys or secrets

• .gitignore protection for sensitive files

Use Cases

Setting up HTTP server for remote A2A communication

• Load http template

• Configure CORS

• Set environment variables

• Validate configuration

Configuring STDIO for local agent communication

• Load stdio template

• Configure process pipes

• Test connectivity

Implementing SSE for real-time agent updates

• Load sse template

• Configure event streams

• Set up CORS

• Test streaming

Setting up WebSocket for bidirectional agent chat

• Load websocket template

• Configure connection handling

• Set up authentication

• Test bidirectional flow