clarion

Chat room-based messaging MCP server for inter-session communication in Claude Code.

Multiple Claude Code sessions (terminals) can join chat rooms and exchange messages. Each session can set a unique name and role per room, guiding how it thinks, requests, and responds.

한국어 문서

Installation

npx -y @baebyeongil/clarion

Register with Claude Code

claude mcp add clarion --scope user --transport stdio -- npx -y @baebyeongil/clarion

Or add directly to ~/.claude.json:

{
  "mcpServers": {
    "clarion": {
      "command": "npx",
      "args": ["-y", "clarion"]
    }
  }
}

Run with Channels

To enable real-time message push between sessions:

claude --dangerously-load-development-channels server:clarion

Without this flag, MCP tools work but messages won't be pushed automatically to other sessions.

Permissions (Recommended)

Add the following to ~/.claude/settings.json to auto-approve all clarion tools:

{
  "permissions": {
    "allow": [
      "mcp__clarion__room_join",
      "mcp__clarion__room_send",
      "mcp__clarion__room_list",
      "mcp__clarion__room_leave",
      "mcp__clarion__room_delete",
      "mcp__clarion__room_my",
      "Read"
    ]
  }
}

Tools

Session ID is automatically assigned from the process PID. No need to specify it manually.

| Tool | Parameters | Description | |-|-|-| | room_join | room, name, role | Create or join a room. Auto-creates if not exists. Updates name/role on rejoin | | room_send | room, content | Send a message to all other members in the room | | room_list | (none) | List all rooms with members | | room_leave | room | Leave a room | | room_delete | room | Delete a room (creator only) | | room_my | (none) | List rooms you belong to with your name/role |

Usage

1. Join a room

Session A (Terminal 1):

room_join({ room: "dev", name: "Frontend", role: "Frontend developer. Handles UI/UX requests and responses." })

Session B (Terminal 2):

room_join({ room: "dev", name: "Backend", role: "Backend API developer. Handles data models and API design." })

2. Send a message

Session A:

room_send({ room: "dev", content: "What is the response schema for the login API?" })

3. Check my rooms

room_my()

Storage

Data is stored as JSON files in ~/.claude/mcp-clarion/.

~/.claude/mcp-clarion/
  rooms.json
  inboxes/{roomName}/{sessionId}.json

License

MIT