MCP-Connected Agent

spec.agent.mcp configures how an agent uses MCP (Model Context Protocol): mcp.servers lists the servers it connects to at runtime to discover and call external tools, on top of its locally generated spec.tools, and the surrounding fields tune the client. It lives under spec.agent because it only makes sense once an LLM is driving. This agent connects to two http servers - the only transport the reference consumer wires today, see What the reference consumer wires.

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

  agent:
    provider: openai
    model: gpt-4.1
    systemPrompt: |
      You are a coding assistant. Use the docs MCP server to look up
      references and the GitHub MCP server to inspect issues and PRs.
    mcp:
      enabled: true
      endpoint: /mcp
      refreshInterval: 5m
      dialTimeout: 30s
      callTimeout: 30s
      maxRetries: 0
      retryInterval: 2s
      retryMaxInterval: 30s
      servers:
        - name: github
          transport: http
          url: https://mcp.example.com/github
          headers:
            Authorization: Bearer ${GITHUB_MCP_TOKEN}
        - name: docs
          transport: http
          url: https://mcp.example.com/docs

  server:
    port: 8080

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

Highlights

• http reaches a remote endpoint. Both servers are addressed by url, and github carries an Authorization header. Placeholders like ${GITHUB_MCP_TOKEN} are resolved by the consumer - the schema doesn't interpret them. See Secrets & interpolation.
• http is what gets wired today. The schema also accepts stdio (command/args/env) and sse, but adl-cli drops those entries from A2A_MCP_SERVERS with a warning and generates the MCP client for Go agents only - see What the reference consumer wires.
• Only name + transport are required. The remaining fields are the connection details for the chosen transport, and the schema doesn't enforce which combination is present, so consumers stay lenient.
• 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.
• mcp turns the client on and sets the defaults. mcp.servers lists the servers; the surrounding mcp fields are the client runtime config. It is disabled by default - here enabled: true wires it in. Each field is the default for the matching A2A_MCP_* environment variable, which overrides it at runtime; the values shown are the built-in defaults, so this block is equivalent to just enabled plus servers. With enabled: false (or the block omitted) no MCP client is generated at all.