@rebind.gg/mcp-server

Stdio MCP server that turns Rebind into a computer-use toolkit: screenshots, verified clicks, keyboard input, window control, and direct Luau scripting on the connected machine — driven over real HID, not synthetic OS events.

Requirements

• Bun >= 1.1 (the server runs via bunx)
• The Rebind app running its Remote Access relay: remote.luau (recommended) or remote_access.lua (protocol >= 1.1.0)

Older copies of remote_access.lua called hid.press outside a coroutine, so clicks silently failed. Use remote.luau or a current remote_access.lua.

Install

One command writes the correct config for whichever clients you name — Claude Code, Cursor, Codex, OpenCode, VS Code, Windsurf, Zed, and more — via add-mcp:

npx add-mcp "bunx @rebind.gg/mcp-server" --name rebind \
  --env REBIND_URL=ws://127.0.0.1:19561 \
  -g -a claude-code -a cursor -a codex -a opencode

Drop -a <agent> for the clients you want, or pass --all. -g installs globally; omit it for project-local config. Restart the client afterward.

Manual configuration

Any MCP client takes the stdio block directly:

{
  "mcpServers": {
    "rebind": {
      "command": "bunx",
      "args": ["@rebind.gg/mcp-server"],
      "env": { "REBIND_URL": "ws://127.0.0.1:19561" }
    }
  }
}

Verify the relay is reachable

bunx @rebind.gg/mcp-server --selftest

Connects, takes a capture, and reports the display — the fastest way to catch the #1 first-run failure (relay not loaded).

Tools

| Tool | What it does | | --- | --- | | screenshot | Capture a display (cursor marked with a crosshair). All coordinates the model emits are pixels in the most recent screenshot. | | screenshot_window | Capture one window by title substring (or the active window) — smaller, cheaper, monitor-proof. | | zoom | Re-capture a region of the last screenshot at native resolution, for small text. Read-only. | | click | Move to a point and click (left/right/middle, optional double). Landing position is verified and corrected before pressing. | | move_mouse | Move without clicking, with the same verification. | | type | Type text into the focused element. | | key | Press a key or combo, e.g. Enter, LCtrl+L, LAlt+Tab. | | scroll | Scroll the wheel at the cursor (positive = up). | | run_lua | Run a Luau script on the connected machine and return its return value as JSON — the fast path for any deterministic sequence (launch apps, place windows, shell commands, pixel search). | | lua_docs | Full Luau SDK type definitions for run_lua. | | list_displays / list_windows / focus_window / active_window | Display and window enumeration and control. | | get_cursor / wait / calibrate | Cursor readback, pauses, and the mouse scale probe. |

Configuration

| Env var | Default | Purpose | | --- | --- | --- | | REBIND_URL | ws://127.0.0.1:19561 | Relay WebSocket URL. | | REBIND_TOKEN | — | Required when the relay has an auth token set (the Auth token panel field on remote.luau, or AUTH_TOKEN on remote_access.lua). | | REBIND_AGENT_LOG | off | Path to append one JSONL line per tool call ({ts, tool, ok, latency_ms, note}). No screenshot bytes, no user content. |

How it works

Verified clicks. click and move_mouse reach an absolute screen point by reading the real OS cursor and sending relative HID deltas (which map 1:1 to pixels), correcting against the true cursor until it lands. This sidesteps the relay's own absolute move, whose delta comes from a cached cursor position that goes stale and flings the pointer to a screen edge.

Calibration. A mouse scale probe runs on the first click/move_mouse. If pointer ballistics are detected (enhance pointer precision, DPI mismatch), the probe reports it, since acceleration would break the 1:1 assumption. Re-run it any time with calibrate.

One queue. There is one physical cursor and keyboard, so tool calls are serialized: parallel calls from the model run one after another instead of interleaving HID input.

One coordinate space. All results are reported in the pixel space of the last screenshot — the same space the model emits — so no rescaling math ever falls on the model.

Develop

bun test packages/mcp-server/tests/
bun run --cwd packages/mcp-server typecheck

License

MIT © US Input Company