AndroidBackButton
AndroidBackButton action, Trigger the system "back" operation on Android devices
This record as markdown: /tools/android/androidbackbutton.md
What AndroidBackButton does on Android
AI agents invoke AndroidBackButton to trigger actions in Android. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.
| Parameter | Type | Required | Description |
|---|---|---|---|
android.deviceId | string | — | Android device ID (from adb devices) |
android.useScrcpy | boolean | — | Enable scrcpy accelerated screenshots |
android.aiActContext | string | — | Background knowledge passed to aiAct. Default: no extra context. |
android.waitAfterAction | number | — | Wait time in milliseconds after each action execution. Default: 300ms. |
android.replanningCycleLimit | integer | — | Maximum number of replanning cycles for aiAct. Default: model adapter default. |
android.screenshotShrinkFactor | number | — | Screenshot shrink factor before sending images to AI. Default: 1; high values may reduce recognition quality, especially on mobile. |
Parameters from the server's own tool schema.
Why AndroidBackButton is rated High
This tool executes a system command on an Android device (simulating a back button press), which triggers real device behavior. While the action itself is reversible and not destructive, it falls into the Execute category because it runs an external operation whose effects depend on the current app/system state and context.
From the tool's definition Tool description states it will "Trigger the system back operation on Android devices" - this executes a device-level action with external side effects.
Attacks that exploit this kind of access
The rule that runs AndroidBackButton safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Android, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For AndroidBackButton, this is the rule to start with:
AndroidBackButton stays usable, but rate-capped: a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Android, apply this rule, and every AndroidBackButton call is checked against it from then on.
Questions about AndroidBackButton
AndroidBackButton action, Trigger the system "back" operation on Android devices. It is categorised as a Execute tool in the Android MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
AndroidBackButton accepts 6 parameters: android.deviceId, android.useScrcpy, android.aiActContext, android.waitAfterAction, android.replanningCycleLimit, android.screenshotShrinkFactor. The full parameter table on this page comes from the server's own tool schema.
Register the Android MCP server in PolicyLayer and add a rule for AndroidBackButton: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Android. Nothing to install.
AndroidBackButton is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the AndroidBackButton rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for AndroidBackButton. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
AndroidBackButton is provided by the Android MCP server (@midscene/android-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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