mcp-terminal-share

An MCP server that lets two or more Claude Code terminals on the same machine talk to each other. Register each terminal with a short name, then send messages between them.

┌──────────────┐                      ┌──────────────┐
│  terminal A  │ ── send_message ──►  │  terminal B  │
│              │ ◄── send_message ──  │              │
└──────────────┘                      └──────────────┘
        │              file-based              │
        └──────► ~/.claude/terminal-messages ──┘

Why

Pair-running two Claude Code sessions and want one to hand off a long log or a task summary to the other? That's it.

Install

Wire it into Claude Code's MCP config (Claude Code → ~/.claude.json or via the CLI):

claude mcp add terminal-share -- npx -y mcp-terminal-share

Or by hand in your MCP config:

{
  "mcpServers": {
    "terminal-share": {
      "command": "npx",
      "args": ["-y", "mcp-terminal-share"]
    }
  }
}

Requires Node.js 18+.

Tools

Names must match ^[A-Za-z0-9_-]{1,32}$. Message content is capped at 1 MB, summary at 500 B.

Suggested slash commands

If you already use the bundled t-rg / t-list / t-send / t-get / t-watch skills, they map 1:1 onto the tools above.

Show the registered name in your statusline

After a successful register, the server writes a tiny session record keyed by a hash of the working directory:

~/.claude/terminal-messages/sessions/<sha256(cwd)[:16]>.json

The MCP server, your statusline, and any helper subprocess it spawns all inherit cwd from the same Claude Code session, so they can find each other without any extra plumbing.

claude-hud

Add --extra-cmd "mcp-terminal-share-label" to your statusline command:

{
  "statusLine": {
    "type": "command",
    "command": "claude-hud --extra-cmd \"mcp-terminal-share-label\""
  }
}

The bundled mcp-terminal-share-label bin reads the record for the current cwd and outputs claude-hud's expected {"label": "📟 <name>"} (or {} when nothing is registered). Override the emoji/prefix with MCP_TERMINAL_SHARE_LABEL_PREFIX.

Other statuslines

Roll your own. The minimal Node version:

import { readFileSync } from "node:fs";
import { join } from "node:path";
import { homedir } from "node:os";
import { createHash } from "node:crypto";

const key = createHash("sha256").update(process.cwd()).digest("hex").slice(0, 16);
try {
  const { name } = JSON.parse(
    readFileSync(
      join(homedir(), ".claude", "terminal-messages", "sessions", `${key}.json`),
      "utf-8",
    ),
  );
  process.stdout.write(`📟 ${name}`);
} catch {
  // not registered
}

The file is removed automatically when the MCP server shuts down.

Known limitation: if you open two Claude Code sessions in the same directory, the later one's register overwrites the earlier one's session record. This only affects the statusline label — message routing between terminals is unaffected.

How it works

• Each terminal writes its registration to ~/.claude/terminal-messages/terminals/<name>.json.

• Messages are dropped into ~/.claude/terminal-messages/messages/to_<recipient>_<ts>_<rand>.json.

• A session record for statusline consumers lives at ~/.claude/terminal-messages/sessions/<sha256(cwd)[:16]>.json.

• Liveness uses a 5 s heartbeat; records older than 30 s whose owning PID is also dead are reaped on read.

• Messages older than 24 h are reaped on read, and a per-recipient queue cap of 100 prevents runaway buildup.

• All file writes go through a temp-file + rename for atomicity.

Override the storage root with MCP_TERMINAL_SHARE_DIR (mostly useful for tests).

Security model

• Local, single-user, single-host. Anyone with read access to ~/.claude/terminal-messages can read or spoof messages. This is fine on a personal dev machine and explicitly out of scope to defend otherwise.

• No network surface. Communication is purely through the local filesystem; nothing listens on a port.

• Input validation. Names are regex-validated to prevent path traversal; content size is capped.

If you need cross-machine sharing or untrusted multi-tenant isolation, this is the wrong tool — reach for a real message bus.

Development

npm install
npm test

Tests use Node's built-in node:test runner with isolated temp dirs (no extra deps).

License

MIT