MCP-Connected Agent

spec.agent.mcps lists the MCP (Model Context Protocol) servers an agent connects to at runtime to discover and call external tools, on top of its locally generated spec.tools. It lives under spec.agent because it only makes sense once an LLM is driving. This agent connects to two servers over two different transports.

apiVersion: adl.inference-gateway.com/v1
kind: Agent
metadata:
  name: devtools-agent
  description: Coding assistant that reaches external tools over MCP (stdio + http)
  version: "0.2.0"
  tags:
    - developer-tools
spec:
  capabilities:
    streaming: true
    pushNotifications: false
    stateTransitionHistory: true

  agent:
    provider: openai
    model: gpt-4.1
    systemPrompt: |
      You are a coding assistant. Use the filesystem MCP server to read
      local files and the GitHub MCP server to inspect issues and PRs.
    mcps:
      - name: filesystem
        transport: stdio
        command: npx
        args:
          - -y
          - "@modelcontextprotocol/server-filesystem"
          - /workspace
        env:
          LOG_LEVEL: info
      - name: github
        transport: http
        url: https://mcp.example.com/github
        headers:
          Authorization: Bearer ${GITHUB_MCP_TOKEN}

  server:
    port: 8080

  language:
    go:
      module: github.com/example/devtools-agent
      version: "1.26"

Highlights

• stdio launches a local subprocess. filesystem is started with command + args (here npx ... server-filesystem /workspace) and the agent talks to it over stdin/stdout. env sets variables the subprocess needs.
• http reaches a remote endpoint. github is a remote server addressed by url, with headers carrying an Authorization token. Placeholders like ${GITHUB_MCP_TOKEN} are resolved by the consumer - the schema doesn't interpret them. See Secrets & interpolation.
• Only name + transport are required. The remaining fields are the connection details for the chosen transport; the schema doesn't enforce which combination is present, so consumers stay lenient. (sse is the third accepted transport.)
• MCP complements spec.tools. Generated tools are deterministic entrypoints you own; MCP servers are external capabilities discovered at runtime. An agent can use either or both.