Argent: let your AI agent test the mobile app it just changed.

What is Argent?

Argent is a free toolkit from Software Mansion that lets an AI coding agent use a phone app the way a person would. The agent opens the app in the iOS simulator or the Android emulator, taps, types, scrolls and takes screenshots.

Without it, an agent writes mobile code and stops. Someone on the team has to open the app and check the change by hand. With Argent, the agent checks its own work before anyone looks.

What does Argent do?

• Drives the app. Tap, swipe, scroll, type and press hardware buttons on the iOS simulator, the Android emulator and real Android devices.
• Reads the screen. Screenshots, plus a list of what is on screen and where, so the agent taps the right thing and does not guess.
• Records and replays a flow. Walk through a flow once, then run the same steps again after every fix.
• Profiles the app. It finds slow screens, extra re-renders and memory leaks, and compares a fix against the run before it.
• Debugs React Native. It reads logs, inspects the component tree and reloads the app.

It also works on Apple TV, Android TV, Fire TV, and desktop apps built on Electron or Chromium.

Why use Argent?

An agent that cannot check its own change makes a person the checker. That person becomes the slow part of every mobile task.

With Argent the agent finishes the job: it makes the change, opens the app, walks through the screen and shows a screenshot of the result. You review something that has already been tried, not something that compiled.

How do you set up Argent?

Run this in your project. It installs Argent, finds your editor and connects the two:

npx @swmansion/argent@latest init

If you would rather add the MCP server by hand, install it once:

npm install -g @swmansion/argent

Then add it to your project's .mcp.json:

{
  "mcpServers": {
    "argent": {
      "type": "stdio",
      "command": "argent",
      "args": ["mcp"]
    }
  }
}

You need Node.js 18 or later. The iOS simulator needs a Mac with Xcode. The Android emulator needs adb.

How we use Argent

We use Argent on Kidtime and Pouch Buddy, two of our own mobile apps. Most of that use is profiling: making the app feel snappier and finding re-renders that do not need to happen.

• Profiling, to make the app snappier. The agent profiles a slow screen, finds what is taking the time, fixes the top one to three problems, then profiles it again. "Made it faster" with no measurement does not count.
• Finding re-renders that do not need to happen. The profiler shows which parts of a screen redraw and how often. The agent finds the ones that redraw when nothing they show has changed, and stops them.
• We record a flow once and replay it. The agent replays the same taps before and after a fix, so the two runs can be compared.
• Every screen change gets checked in the simulator. After the agent changes a screen, it opens the app, walks through the flow and takes a screenshot. Before and after shots use the same device and the same data, so the only difference is the change.
• The agent reads the screen before every tap. Our rule is that it never picks tap coordinates from a screenshot. It asks Argent what is on screen first, because a guessed tap lands in the wrong place.