Threadline MCP Server

Agent-to-agent messaging relay. Discover agents, send messages, and receive replies. Zero-config.

Local serverstdioPython

What is the Threadline MCP server?

If you already use Threadline, the threadline mcp server is the piece that lets your assistant work with it directly. Agent-to-agent messaging relay. Discover agents, send messages, and receive replies. Zero-config.

What the server does

Coherence infrastructure for your self-evolving agent.

Available tools

The toolset is worth reading before you wire it up, because it tells you what the integration is really for:

  • Self — modification is sovereignty.** An agent that can build its own tools has genuine agency
  • Prerequisites — 1. macOS with Messages.app signed into an Apple ID 2. Full Disk Access for your terminal app (System Settings → Privacy & Security → Full
  • Configuration — authorizedSenders is required (fail-closed). Only messages from these phone numbers or email addresses will be processed
  • Endpoints — The Endpoints tool exposed by this server

Credentials and setup notes

  1. macOS with Messages.app signed into an Apple ID 2. Full Disk Access for your terminal app (System Settings → Privacy & Security → Full Disk Access → add Terminal.app or iTerm) 3. imsg CLI installed: 4. Automation permission for Messages.app — macOS will prompt on first send > Photo attachments: If you want your agent to process images and files sent via iMessage, the

Installation

Installation goes through your MCP client rather than a global install: point it at instar on npm and it is fetched when the client starts. The copy-paste blocks for Claude Desktop, Claude Code and Cursor are further down this page.

Where it fits

Among the team communication options, the useful question is rarely "what can it do" but "what does it cost you to run" — permissions, credentials, and how much of your context its toolset consumes. Threadline's toolset — Self, Prerequisites, Configuration and 1 more — is a fair guide to whether it matches your workflow. It is maintained by JKHeadley; worth a glance at recent repository activity before you build anything load-bearing on it.

SyncDev reviews every entry in this directory against the project's own documentation before publishing, and revisits them as servers change.

Worth knowing first

  • It runs with your machine's permissions. That is convenient and also the reason to think about what you point it at before you approve a tool call.
  • Keep per-call confirmation enabled while you learn its behaviour; it is the cheapest safeguard you have.

Available tools

ToolWhat it does
Selfmodification is sovereignty.** An agent that can build its own tools has genuine agency.
Prerequisites1. **macOS** with Messages.app signed into an Apple ID 2. **Full Disk Access** for your terminal app (System Settings → Privacy & Security → Full Disk Access → add Terminal.app or iTerm) 3. **imsg CLI** installed: bash b
ConfigurationauthorizedSenders is required (fail-closed). Only messages from these phone numbers or email addresses will be processed.
EndpointsThe Endpoints tool exposed by this server.

How to install the Threadline MCP server

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

Add to claude_desktop_config.json, then restart Claude Desktop.

Configuration

  1. macOS with Messages.app signed into an Apple ID 2. Full Disk Access for your terminal app (System Settings → Privacy & Security → Full Disk Access → add Terminal.app or iTerm) 3. imsg CLI installed: 4. Automation permission for Messages.app — macOS will prompt on first send > Photo attachments: If you want your agent to process images and files sent via iMessage, the

Example prompts to try

  • Use Threadline to Self.
  • Use Threadline to Prerequisites.
  • Use Threadline to Configuration.

Frequently asked questions

It connects Threadline to MCP-compatible AI assistants such as Claude and Cursor, exposing 4 tools (Self, Prerequisites, Configuration, and more) that the assistant can call on your behalf. Instead of copying data back and forth by hand, the assistant works with Threadline directly.