ADK Agent Extension

Overview

Use adk-agent-extension as an MCP server that any MCP-capable agent client can connect to.

Use this for:

• ADK discovery (list_adks, list_adk_agents)
• ADK chat/session flow (create_session, send_message_to_agent, streaming/session helpers)
• ADK helper operations (create/deploy/evaluate/list tools/safety/visualize)

Workflow

1. Build artifacts locally when needed:

bun install
bun run build

2. Register MCP stdio server in the target client:
   • command: node
   • args: ["/absolute/path/to/adk-agent-extension/dist/google-adk-agent-extension.js"]
3. Reopen/reload the client and verify tools are visible.
4. Run ADK flow:
   • list_adks
   • list_adk_agents
   • create_session
   • send_message_to_agent

Use client-specific config examples from references/client-configs.md.

Gemini CLI Setup (Optional Client-Specific Shortcut)

For Gemini CLI users, install directly:

gemini extensions install https://github.com/simonliu-ai-product/adk-agent-extension

Bundled MCP Server

The repo already defines MCP server wiring:

• File: gemini-extension.json
• Key: mcpServers.nodeServer
• Command: node
• Entrypoint: ${extensionPath}/dist/google-adk-agent-extension.js

Implication:

• In Gemini CLI extension mode, MCP registration is automatic on install.
• In other clients, manually register equivalent stdio config.

Portable Tool Surface (All MCP Clients)

• list_adks
• list_adk_agents
• create_session
• send_message_to_agent
• stream_message_to_agent
• manage_chat_session
• create_agent
• deploy_agent
• evaluate_agent
• list_agent_tools
• scan_agent_safety
• visualize_agent_system

Gemini-Only Slash Commands

• /adk-ext:list_adks
• /adk-ext:list_adk_agent
• /adk-ext:agent_chat
• /adk-ext:interactive_chat
• /adk-ext:config_add_server
• /adk-ext:config_list_servers
• /adk-ext:config_remove_server
• /adk-ext:create_agent
• /adk-ext:deploy_agent
• /adk-ext:evaluate_agent
• /adk-ext:list_agent_tools
• /adk-ext:scan_safety
• /adk-ext:visualize

Configuration

Manage ADK server endpoints through adk_agent_list.json (extension root) or the config commands above.

Example:

{
  "agents": [
    { "name": "my-adk-server", "url": "https://my-adk-server.example.com" }
  ]
}

Troubleshooting

• If tools are missing, confirm your client is MCP-capable and loaded the stdio server config.
• If MCP calls fail, ensure dist/google-adk-agent-extension.js exists and node is available.
• If agent discovery fails, verify server URLs in adk_agent_list.json.
• If command names differ by client UI, call tools directly from MCP tool picker by exact tool name.

Resources

references/

• references/client-configs.md: quick MCP client configuration snippets for Codex, Claude Code, Cursor, Cline, and Gemini CLI.

assets/

• assets/mcp/adk-agent-extension.stdio.json: reusable MCP stdio server template you can copy into client MCP settings.