set_session_storage

A write tool on the Playwright MCP server.

SERVERPlaywright MCP Server SOURCEalexrwilliam/playwright-mcp-server

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/alexrwilliam-playwright-mcp-server/set-session-storage.md

WHAT IT DOES

What set_session_storage does on Playwright MCP Server

AI agents use set_session_storage to create or update resources in Playwright MCP Server, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Playwright MCP Server environment.

RISK

Why set_session_storage is rated Medium

This tool creates or modifies session storage data in the browser, which is reversible but affects application state. It does not delete data (Destructive), execute arbitrary code (Execute), or move money (Financial).

From the tool's definition Tool name 'set_session_storage' indicates modification of browser session storage. Playwright is a browser automation framework; setting session storage modifies client-side data that can affect application state and behavior.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs set_session_storage safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Playwright MCP Server, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For set_session_storage, this is the rule to start with:

set_session_storage Rate-limited

set_session_storage stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "set_session_storage": {
      "limits": [
        {
          "counter": "set_session_storage_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Playwright MCP Server, apply this rule, and every set_session_storage call is checked against it from then on.

FAQ

Questions about set_session_storage

What does the set_session_storage tool do? +

set_session_storage is a write tool on the Playwright MCP Server MCP server. It is categorised as a Write tool in the Playwright MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on set_session_storage? +

Register the Playwright MCP Server MCP server in PolicyLayer and add a rule for set_session_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 Playwright MCP Server. Nothing to install.

What risk level is set_session_storage? +

set_session_storage is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit set_session_storage? +

Yes. Add a rate_limit block to the set_session_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.

How do I block set_session_storage completely? +

Set action: deny in the PolicyLayer policy for set_session_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.

What MCP server provides set_session_storage? +

set_session_storage is provided by the Playwright MCP Server MCP server (alexrwilliam/playwright-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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