agentsmcp-adapter

MCP server adapter for agentsmcp (the AgentMailbox protocol). Exposes AgentMailbox to any MCP-aware client. Each MCP server instance represents one agent identity.

Install

npm install -g agentsmcp-adapter

This pulls in the agentsmcp SDK as a dependency — no separate setup.

Configuration

Required:

• AGENTSMCP_AGENT_ID — the agent identity this MCP server represents (e.g. claude@local).

Optional:

• AGENTSMCP_SERVER — HTTP server URL, defaults to http://localhost:3000.
• AGENTSMCP_API_KEY — passed through as a Bearer token.

CLI flags mirror env vars and take precedence:

agentsmcp-adapter --agent-id claude@local --server http://localhost:3000

Make sure the AgentMailbox HTTP server is running first (npx agentsmcp-server or npm start in a clone).

Claude Desktop config

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "agentsmcp": {
      "command": "npx",
      "args": ["-y", "agentsmcp-adapter"],
      "env": {
        "AGENTSMCP_AGENT_ID": "claude@local",
        "AGENTSMCP_SERVER": "http://localhost:3000"
      }
    }
  }
}

Cursor / Continue / other MCP clients

Same shape — point them at npx -y agentsmcp-adapter with AGENTSMCP_AGENT_ID set.

Available tools

| Tool | Description | | ----------------------- | ---------------------------------------------------------------------- | | agentsmcp_send | Send a message to another agent; auto-creates a thread if needed. | | agentsmcp_receive | Get unread messages with full thread context attached. | | agentsmcp_unread | List unread context frames without consuming them. | | agentsmcp_sync | Rejoin a thread with full assembled context. | | agentsmcp_threads | List all threads this agent is part of. | | agentsmcp_mark_read | Mark a thread as read for this agent. | | agentsmcp_reply_all | Reply to every visible participant on a thread. | | agentsmcp_participants| List visible participants on a thread with their roles (to/cc/bcc). |

Two read-only MCP resources are also exposed:

• agentsmcp://mailbox — JSON listing of all threads.
• agentsmcp://thread/{threadId} — JSON with thread context and participants.

Why MCP

A two-agent system used to require both agents to install the JS or Python SDK. With this adapter, any MCP-aware client gets a mailbox for free — no SDK, no glue code. Cross-tool context sync becomes a config-file change.