Take a screenshot of the iOS device screen. Returns the image that can be viewed directly.
AI agents call screenshot to retrieve information from Expo Dev Build MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The screenshot tool only captures and retrieves the current visual state of the iOS device screen. It has no side effects: it does not modify any data, execute code, delete anything, or commit financial transactions. This is a straightforward Read operation analogous to viewing a display.
From the tool's definition Tool name is 'screenshot' and description states it 'takes a screenshot' and 'returns the image'—a read-only retrieval of visual data with no modification, deletion, or execution of device actions.
Attacks that exploit this kind of access
Take a screenshot of the iOS device screen. Returns the image that can be viewed directly. It is categorised as a Read tool in the Expo Dev Build MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Expo Dev Build MCP Server MCP server in PolicyLayer and add a rule for 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 Expo Dev Build MCP Server. Nothing to install.
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 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 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.
screenshot is provided by the Expo Dev Build MCP Server MCP server (ryan-crabbe/expo-dev-build-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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