take_snapshot
Take a text snapshot of the currently selected page based on the a11y tree. The snapshot lists page elements along with a unique identifier (uid). Always use the latest snapshot. Prefer taking a snapshot over taking a screenshot. The snapshot indicates the element selected in the DevTools Element...
This record as markdown: /tools/1600822305-js-reverse-mcp/take-snapshot.md
What take_snapshot does on Js Reverse
AI agents call take_snapshot to retrieve information from Js Reverse without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Why take_snapshot is rated Low
This tool retrieves and queries the current state of a web page's DOM structure via the accessibility tree. It is purely observational—it gathers information about page elements without creating, modifying, deleting, or executing any code. The data is read-only and used for inspection and debugging purposes. No action is taken on the page itself.
From the tool's definition Tool takes a snapshot of the page based on accessibility tree and lists page elements with identifiers. The description explicitly states it 'take[s] a text snapshot' and 'lists page elements', indicating data retrieval with no modifications or side effects.
Attacks that exploit this kind of access
The rule that runs take_snapshot safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Js Reverse, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For take_snapshot, this is the rule to start with:
take_snapshot is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Js Reverse, apply this rule, and every take_snapshot call is checked against it from then on.
Questions about take_snapshot
Take a text snapshot of the currently selected page based on the a11y tree. The snapshot lists page elements along with a unique identifier (uid). Always use the latest snapshot. Prefer taking a snapshot over taking a screenshot. The snapshot indicates the element selected in the DevTools Elements panel (if any). It is categorised as a Read tool in the Js Reverse MCP Server, which means it retrieves data without modifying state.
Register the Js Reverse MCP server in PolicyLayer and add a rule for take_snapshot: 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 Js Reverse. Nothing to install.
take_snapshot 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 take_snapshot 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 take_snapshot. 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.
take_snapshot is provided by the Js Reverse MCP server (1600822305/js-reverse-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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