AI agents call browser_storage_get_service_workers to retrieve information from Browser without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and retrieves information about service worker registrations and their current state. It performs a passive read operation that does not modify, execute, delete, or move any data. The lack of action verbs like 'set', 'execute', 'delete', or 'modify' confirms this is a Read category tool with low severity, as it merely exposes existing browser state information.
From the tool's definition Tool name contains 'get' and description states 'Get service worker registrations and their state' — a retrieval operation with no modification or side effects.
Attacks that exploit this kind of access
Get service worker registrations and their state (see browser_docs). It is categorised as a Read tool in the Browser MCP Server, which means it retrieves data without modifying state.
Register the Browser MCP server in PolicyLayer and add a rule for browser_storage_get_service_workers: 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 Browser. Nothing to install.
browser_storage_get_service_workers 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 browser_storage_get_service_workers 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 browser_storage_get_service_workers. 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.
browser_storage_get_service_workers is provided by the Browser MCP server (ricardodeazambuja/browser-mcp-server). 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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