agent_with_mcp_config

MCP examples (agent_with_mcp_config, agent_with_mcp_client)

These two programs use the same env-driven MCP transport but wire the agent differently:

• agent_with_mcp_config — agent.WithMCPConfig(agent.MCPServers{<serverName>: mcpCfg}). The SDK builds the default MCP client per server.
• agent_with_mcp_client — mcpclient.NewClient(<serverName>, transport, opts...) then agent.WithMCPClients(client).

Prerequisites

• examples/.env with LLM_* set (see ../.env.defaults; defaults load automatically).
• AGENT_RUNTIME=temporal only if you want durable workflows — then Temporal per temporal-setup.md or task -t examples/Taskfile.yml infra:temporal:up.

Configure MCP

Transport must be set with MCP_TRANSPORT: stdio or streamable_http (aliases in .env.defaults).

• Remote — streamable_http: set MCP_STREAMABLE_HTTP_URL. Auth optional: MCP_BEARER_TOKEN, or OAuth trio MCP_CLIENT_ID + MCP_CLIENT_SECRET + MCP_TOKEN_URL (OAuth wins over bearer when all three are set). MCP_SKIP_TLS_VERIFY=true for dev TLS only.
• Local — stdio: set MCP_STDIO_COMMAND and optional MCP_STDIO_ARGS (JSON string array) and MCP_STDIO_ENV (JSON string→string object).

Shared optional knobs: MCP_SERVER_NAME, MCP_TIMEOUT_SECONDS, MCP_RETRY_ATTEMPTS, MCP_ALLOW_TOOLS / MCP_BLOCK_TOOLS (comma-separated; only one list type).

See ../.env.defaults for every variable.

Run

From the examples/ directory:

go run ./agent_with_mcp_config
go run ./agent_with_mcp_config "List tools you can call."

go run ./agent_with_mcp_client
go run ./agent_with_mcp_client "List tools you can call."

Testing against real MCP servers

This repo does not start an MCP server—you point examples/.env at your server(s). Pick stdio or streamable_http, set MCP_TRANSPORT, then fill in .env.defaults under MCP.

Worked example — TypeScript streamable HTTP (mcp-streamable-http)

git clone https://github.com/invariantlabs-ai/mcp-streamable-http
cd mcp-streamable-http/typescript-example/server
npm install && npm run build
node build/index.js

The server listens on port 8123 by default with MCP at /mcp (override with node build/index.js --port=XXXX). In examples/.env set:

• MCP_TRANSPORT=streamable_http
• MCP_STREAMABLE_HTTP_URL=http://localhost:8123/mcp

Then from examples/:

go run ./agent_with_mcp_config

Quick check (while the server is running):

curl -sS -o /dev/null -w "%{http_code}\n" "http://localhost:8123/mcp"

Modes

Where to find servers and docs

Quick checks before running

• streamable_http: Confirm the URL is reachable from the machine running the example. Example: curl -sS -o /dev/null -w "%{http_code}\n" "$MCP_STREAMABLE_HTTP_URL" — status depends on the implementation.
• stdio: Run the same command line as MCP_STDIO_COMMAND / MCP_STDIO_ARGS in a terminal once to ensure the binary starts.

You still need LLM credentials in examples/.env (and Temporal when using AGENT_RUNTIME=temporal).

Env vars (MCP)

See the MCP_* rows in examples/README.md and ../.env.defaults.