Zeno Mobile Runner

Zeno Mobile Runner

The verification loop for AI coding agents building Expo, React Native, Flutter, and native Android/iOS apps.

Your coding agent can write mobile code, but it cannot see the phone. ZMR is its eyes and hands: a typed mobile control plane that installs and launches apps, observes the UI, taps and types, waits for the screen to settle, asserts state, and exports a replayable trace as proof. The runner does not embed an LLM. Agents stay outside and drive ZMR through MCP, JSON-RPC, CLI JSON, or JSON scenarios.

  

Real on-device screenshots from ZMR traces: the same demo flow driven on an iOS simulator and an Android emulator.

Why agents need this

• Agents can't verify what they can't observe. ZMR returns semantic UI trees with stable selectors, screenshots, and typed action results an agent can reason about — not raw pixels it has to guess at.
• Evidence, not vibes. Every session can write a deterministic trace: events, screenshots, UI hierarchies, timings, assertion results, HTML and JUnit reports, and a redacted shareable bundle.
• Tests fall out for free. After a live agent session, zmr discover turns the trace into a reviewable JSON scenario that replays in CI without an LLM in the loop.

How it works

flowchart LR
    A["AI coding agent<br/>Claude Code · Cursor · custom harness"]
    subgraph zmr["ZMR — one small Zig binary"]
        MCP["MCP server<br/><code>zmr mcp</code>"]
        RPC["JSON-RPC stdio/TCP<br/><code>zmr serve</code>"]
        CLI["CLI + JSON scenarios<br/><code>zmr run</code>"]
        CORE["Core engine<br/>selectors · waits · assertions<br/>scenario runner · trace writer"]
        MCP --> CORE
        RPC --> CORE
        CLI --> CORE
    end
    subgraph devices["Devices"]
        AND["Android emulator/device<br/>ADB · UI Automator · optional shim"]
        IOS["iOS simulator/device<br/>simctl · devicectl · XCTest shim"]
    end
    TRACE["Trace<br/>events.jsonl · screenshots · UI trees<br/>report.html · junit.xml · .zmrtrace"]
    A -- "MCP tools" --> MCP
    A -- "JSON-RPC" --> RPC
    A -- "CLI JSON" --> CLI
    CORE --> AND
    CORE --> IOS
    CORE --> TRACE

No app instrumentation is required on Android. iOS selector actions use an app-local XCTest shim that the wizard scaffolds. ZMR works below the JavaScript/Dart layer, so React Native, Expo, Flutter, and fully native apps are all driven the same way. See docs/frameworks.md.

Five-minute start

Inside a mobile app repo:

npm install --save-dev zeno-mobile-runner   # bun add --dev zeno-mobile-runner
npx zmr-wizard --app-id com.example.mobiletest --package-json
npx zmr doctor --strict --json --config .zmr/config.json

Hook it up to your coding agent (Claude Code shown; any MCP client works):

claude mcp add zmr -- npx zmr mcp --config .zmr/config.json --trace-dir traces/zmr-agent

Claude Code users can instead install the plugin, which bundles the MCP server and a mobile-testing skill:

/plugin marketplace add johnmikel/zeno-mobile-runner
/plugin install zmr@zmr-marketplace

Or in an .mcp.json / MCP client config:

{
  "mcpServers": {
    "zmr": {
      "command": "npx",
      "args": ["zmr", "mcp", "--config", ".zmr/config.json", "--trace-dir", "traces/zmr-agent"]
    }
  }
}

Then ask the agent to verify its own work: "launch the app, walk through onboarding, and show me the trace."

The agent verification loop