AI agents call browser_sessionstorage_clear to permanently remove resources in Playwright — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Session storage clearing is a destructive operation that permanently removes client-side data in the current browsing session. While not as severe as deleting persistent data, it irreversibly wipes session state and cannot be reversed without re-executing the original session operations. Classification as Destructive is appropriate due to the irreversible nature of the action.
From the tool's definition Tool name 'browser_sessionstorage_clear' indicates irreversible deletion of session storage data. The '_clear' suffix denotes a destructive operation that cannot be undone.
Documented attack patterns abuse exactly the kind of access browser_sessionstorage_clear 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_sessionstorage_clear:
{
"version": "1",
"default": "deny",
"hide": [
"browser_sessionstorage_clear"
]
}browser_sessionstorage_clear disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.
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browser_sessionstorage_clear. It is categorised as a Destructive tool in the Playwright MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Playwright MCP server in PolicyLayer and add a rule for browser_sessionstorage_clear: 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_sessionstorage_clear is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the browser_sessionstorage_clear 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_sessionstorage_clear. 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_sessionstorage_clear 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.