AI agents call browser_get_storage to retrieve information from Byob without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves browser storage data (localStorage, sessionStorage, etc.) without creating, modifying, or deleting anything. It has no side effects and is explicitly labeled as a 'Read' operation. While it could expose sensitive data if misused, the risk is limited to information disclosure rather than destructive or financial impact.
From the tool's definition Tool name 'browser_get_storage' and description 'Read' indicate retrieval of stored data without modification. The server context shows this tool accesses browser state (storage, cookies, console logs, HTML) for information gathering.
Attacks that exploit this kind of access
Read. It is categorised as a Read tool in the Byob MCP Server, which means it retrieves data without modifying state.
Register the Byob MCP server in PolicyLayer and add a rule for browser_get_storage: 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 Byob. Nothing to install.
browser_get_storage 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_get_storage 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_get_storage. 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_get_storage is provided by the Byob MCP server (wxtsky/byob). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.