Cursor and the iOS simulator: MCP setup
Add Mobster to Cursor with one button in Mobster for Mac, or in mcp.json by hand, then let Cursor's agent check your iOS app's screens on a simulator.
In Mobster for Mac
Settings › Connectors › Add, next to Cursor. Then restart Cursor.
Or by hand
Add the mobster block below to ~/.cursor/mcp.json, or .cursor/mcp.json in a project.
Cursor’s agent can write a SwiftUI screen, and then someone has to open the simulator and look at it. With Mobster’s MCP server in Cursor, the agent does that part: it states what the screen must show, drives your app on a headless simulator Mobster manages, and gets a verdict of passed or failed from assertions on the accessibility tree. It can also use a real iPhone on your Mac’s USB.
You need an Apple silicon Mac with macOS 15 or later and Xcode with an iOS Simulator runtime. A real iPhone also needs Developer Mode and the WebDriverAgent runner, set up in Mobster for Mac (Device setup).
Install Mobster for Mac
Get Mobster for Mac, drag it to Applications and open it. Its MCP server is the agent inside the app, so the command every client starts is this path, with mcp:
/Applications/The first check creates Mobster’s own simulator, boots it headless and builds WebDriverAgent, once per Xcode version. Mobster never touches your own simulators: each one it creates has a name that starts with “Mobster”.
Add the server
In Mobster for Mac, open Settings › Connectors › Use Mobster from… and press Add next to Cursor. It writes the mobster entry for you in ~/, and when the app holds your model key it passes the app’s settings file with --env-file, so Smart uses the same key.
By hand: Cursor reads .cursor/ in a project and ~/ for every project. Put this in one of them:
{ "mcpServers": { "mobster": { "type": "stdio", "command": "/Two details matter. Cursor’s docs say command must be on the system path or a full path, and as a GUI app Cursor may not see the PATH your shell sets up, so the full path is the safe choice. Cursor’s field table also lists "type": "stdio" as required while its examples leave it out; the block above includes it, which works either way. Save the file and restart Cursor.
For Smart, where Mobster runs the steps itself on your OpenAI or Anthropic key, add your env file to args: ["mcp", "--env-file", "~/. Mobster expands the ~ itself. Key-less checks need no key.
Cursor’s docs don’t state a tool-call timeout. Mobster doesn’t depend on a long one: every call returns within 45 seconds and wait within 50, and longer work, such as the first simulator boot, continues under a run_id that the agent polls with wait.
Check it’s connected
Open Customize, then MCPs: mobster should be there, switched on, with its tools listed. If it isn’t, the Output panel (Cmd+Shift+U) has a channel named MCP Logs with the server’s start-up errors. Then ask the agent:
Call mobster's status tool and tell me what it reports.A first check: onboarding
Say your app opens with a short onboarding that asks for notification permission. A prompt for Cursor’s agent:
Build my app for the simulator, then verify that a new user can completeonboarding without allowing notifications and lands on the first lesson.The agent calls verify_start with the absolute app_path, the steps and the expectations, then taps through. A real key-less session on a sample app’s onboarding, from Mobster’s own smoke script on 28 Sep 2026 with the app renamed YourApp, with each call, how long it took and the first line it returned:
verify_start 3.94 s Run 20260928-151841-816e is ready. Drive the app with the refs below, then call verify_finish.tap 1.86 s Tapped “Continue”; the screen changed.tap 2.13 s Tapped “Continue”; the screen changed.tap 1.89 s Tapped “Turn on reminders”; the screen didn't change.screen 0.46 s Screen com.example.yourapp 402×874 pt keyboard: none alert: "“YourApp” Would Like to Send You Notifications …"alert 2.13 s Dismissed the alert "“YourApp” Would Like to Send You Notifications …".tap 4.13 s Tapped “Get started”; the screen changed.wait_for 4.50 s All 1 hold (4.5 s).verify_finish 3.07 s Verdict: passed Complete onboarding. Don't allow notifications. (24.1 s)The simulator was already up. Note the fourth line: the tap didn’t change the screen because the system alert came up, and alert answered it. verify_finish returns the verdict, the report path and the overlay frame. On failed, the agent fixes the code, rebuilds and verifies again.
Add a project rule
Cursor applies project rules from .cursor/, as .mdc files with front matter. With a description and alwaysApply: false, the agent reads the description and pulls the rule in when it’s relevant:
---description: How to verify a change to this iOS app's screens with Mobster before saying it worksalwaysApply: false---After you change a screen in this iOS app, verify it before you say it works.1. Build for the simulator: xcodebuild -scheme <Scheme> -destination 'generic/Save it as .cursor/. A plain .md file there is ignored. If you prefer plain Markdown, Cursor also reads an AGENTS.md at the project root.
Use a real iPhone
The agent calls list_devices, then passes a USB iPhone’s name as device to screen, tap, type_text, swipe, alert, open_url, launch_app and home, with no run_id. Mobster takes the phone’s lock for the session, and stop with the device, or 90 idle seconds, gives it back.
Cursor asks for approval before MCP tools by default. Your approval covers a tool, not a device, so allowing tap while you test on a simulator allows it on your phone as well. Limit the server to the phones you mean:
"args": ["mcp", "--allow-device", "Test iPhone"]To skip the prompt for reads only, list Mobster’s read-only tools in mcpAllowlist in ~/ or the workspace’s .cursor/, as server:tool entries such as "mobster:screen", "mobster:status" and "mobster:list_devices". Avoid "mobster:*", which also allows tap and type_text without asking. Mobster’s MCP annotations mark which tools only read, and its instructions tell the agent to ask before anything that sends, buys, posts or deletes on a real iPhone. A locked phone stops the call at once, and Mobster never enters a passcode.
Troubleshooting
| Symptom | Fix |
|---|---|
| mobster doesn’t start, or shows an error in MCP Logs | Use the full path /Applications/ in command, check that Mobster is in Applications, then restart Cursor |
| The server is listed, but every call asks for approval | That is Cursor’s default. Add the read-only tools to mcpAllowlist |
The first verify_start returns status: "preparing" | The simulator is booting and WebDriverAgent is building. The agent calls wait |
couldnt_run, or no verify tool | reason.fix in the result says what to do. status says why Smart is off |
The MCP reference lists every tool. AI end-to-end tests for iOS explains how the verdict is decided.
Questions
Why does Cursor fail to start the Mobster server?
Cursor is a GUI app and may not see your shell's PATH. Cursor's docs say the command must be on the system path or a full path, so put the full path /Applications/Mobster.app/Contents/MacOS/mobster-agent in the command field and restart Cursor.
Should the Cursor config include "type": "stdio"?
Yes. Cursor's field table marks type as required for a local server while its examples leave it out. Including it works under both readings.
Can Cursor run Mobster's read-only tools without asking?
Yes. Add entries such as mobster:screen and mobster:status to mcpAllowlist in Cursor's permissions.json. Keep the acting tools, like tap and type_text, out of the list so Cursor still asks before them.
How do I connect Cursor to the iOS Simulator?
Add Mobster's MCP server to ~/.cursor/mcp.json, or press Add next to Cursor in Mobster for Mac's Settings › Connectors, then restart Cursor. Its agent can then run your app on a headless simulator Mobster manages, read each screen by element name, tap and type, and get passed or failed from assertions.
Sources
We read each of these on 8 October 2026. Reviewed by Andy Guo on . Corrections are welcome at the GitHub repo.
Cursor’s logo is a trademark of Anysphere, shown only to name the product. Mobster isn’t affiliated with or endorsed by Anysphere.