AI agents call browser_storage_state to retrieve information from Playwright without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The name 'browser_storage_state' suggests it reads/retrieves the current storage state of the browser, which is a read operation. However, with an empty description, there is uncertainty. Storage state can contain sensitive data (session tokens, credentials), making misuse medium severity. Confidence is low due to no description.
From the tool's definition Tool name 'browser_storage_state' and empty description. Based on naming convention, likely retrieves browser storage state (cookies, localStorage, sessionStorage).
Documented attack patterns abuse exactly the kind of access browser_storage_state gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Playwright, and nothing reaches the server without passing your rules. This is the rule we recommend for browser_storage_state:
{
"version": "1",
"default": "deny",
"tools": {
"browser_storage_state": {}
}
}browser_storage_state is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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browser_storage_state. It is categorised as a Read tool in the Playwright MCP Server, which means it retrieves data without modifying state.
Register the Playwright MCP server in PolicyLayer and add a rule for browser_storage_state: 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 Playwright. Nothing to install.
browser_storage_state 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_state 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_state. 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_state is provided by the Playwright MCP server (@playwright/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Playwright, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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68 Playwright tools catalogued and risk-classified — across an index of 43,000+ MCP servers.