MCP Setup

Connect your AI coding agent to the app currently open in LookInside, then inspect its live hierarchy, attributes, and screenshots from the conversation.

What you need

  • LookInside 2.3.11 or later, installed in Applications
  • A target app with LookInsideServer enabled for its Debug build
  • LookInside running and connected to that target
  • An MCP client such as Codex, Claude Code, Cursor, or Windsurf

The MCP server is bundled with the Mac app. There is nothing else to install, and it does not need an API key or network endpoint.

Codex

Add LookInside as a user-level MCP server:

codex mcp add lookinside -- /Applications/LookInside.app/Contents/Resources/lookinside-mcp

Restart Codex if it was already open, then ask it to call ping_host.

Claude Code

Add the same executable over stdio:

claude mcp add --transport stdio --scope user lookinside -- /Applications/LookInside.app/Contents/Resources/lookinside-mcp

Run claude mcp list to confirm the server is registered.

Desktop clients

For Claude Desktop, Cursor, Windsurf, and clients that accept an MCP JSON configuration, add:

{
  "mcpServers": {
    "lookinside": {
      "command": "/Applications/LookInside.app/Contents/Resources/lookinside-mcp",
      "args": []
    }
  }
}

Claude Desktop stores this in ~/Library/Application Support/Claude/claude_desktop_config.json. Restart the client after saving the file.

Verify the connection

  1. 1

    Run the target app and open it in LookInside.

  2. 2

    Ask your agent to ping LookInside and list connected targets.

  3. 3

    Ask it to read the hierarchy before requesting a narrower inspection.

Try this prompt

Use LookInside to inspect the connected app. Find the checkout button, read its relevant attributes, and explain why it appears disabled. Do not modify anything.

What agents can do

Explore

Read and search the live UI hierarchy.

Inspect

Read view details, attributes, methods, and screenshots.

Compare

Capture snapshots and diff UI state before and after an action.

Act

Refresh the hierarchy, invoke methods, or modify supported attributes.

Reading is the safest default. Method calls and attribute changes can affect the running app, so review the exact target and value before approving them. Secure text is redacted, and secure screenshots require explicit acknowledgement.

Troubleshooting

The MCP process exits immediately
Make sure LookInside is running. The bundled server talks to the host app locally and cannot serve inspection data on its own.
No targets are listed
Run the Debug build containing LookInsideServer, then connect to it from the LookInside target list before asking the agent again.
The client cannot find the executable
Confirm that LookInside is installed at /Applications/LookInside.app and that /Applications/LookInside.app/Contents/Resources/lookinside-mcp exists.

Full tool reference

See the canonical GitHub guide for the complete tool catalog, example workflows, and safety notes.

Open the MCP guide on GitHub ↗