AI agents call save_screenshot to retrieve information from uiautomator2 MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
A screenshot tool reads the current visual state of the screen and saves it, producing no side effects on the device state. The description is empty, so confidence is reduced, but the name strongly implies a read/capture operation. Severity is low as misuse only exposes screen content.
From the tool's definition Tool name 'save_screenshot' and server context of Android device control via uiautomator2
Documented attack patterns abuse exactly the kind of access save_screenshot gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and uiautomator2 MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for save_screenshot:
{
"version": "1",
"default": "deny",
"tools": {
"save_screenshot": {}
}
}save_screenshot is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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save_screenshot. It is categorised as a Read tool in the uiautomator2 MCP Server MCP Server, which means it retrieves data without modifying state.
Register the uiautomator2 MCP Server MCP server in PolicyLayer and add a rule for save_screenshot: 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 uiautomator2 MCP Server. Nothing to install.
save_screenshot is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the save_screenshot 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 save_screenshot. 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.
save_screenshot is provided by the uiautomator2 MCP Server MCP server (tanbro/uiautomator2-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from uiautomator2 MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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77 uiautomator2 MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.