browser_sessionstorage_set

A write tool on the Playwright MCP server.

SERVERPlaywright MCP SOURCEalialobidm/playwright-mcp

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/alialobidm-playwright-mcp/browser-sessionstorage-set.md

WHAT IT DOES

What browser_sessionstorage_set does on Playwright MCP

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

RISK

Why browser_sessionstorage_set is rated Medium

This tool modifies browser session storage, which is a reversible write operation. It creates or updates session storage key-value pairs that applications may depend on. While this can influence web application behavior or state, it does not irreversibly destroy data (Destructive), execute arbitrary code (Execute), or move money (Financial).

From the tool's definition Tool name 'browser_sessionstorage_set' indicates it sets session storage values in the browser. The 'set' suffix denotes a write/modification operation. Session storage persists data for the browser session and can affect application behavior.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs browser_sessionstorage_set safely

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

browser_sessionstorage_set Rate-limited

browser_sessionstorage_set 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": {
    "browser_sessionstorage_set": {
      "limits": [
        {
          "counter": "browser_sessionstorage_set_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, apply this rule, and every browser_sessionstorage_set call is checked against it from then on.

FAQ

Questions about browser_sessionstorage_set

What does the browser_sessionstorage_set tool do? +

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

How do I enforce a policy on browser_sessionstorage_set? +

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

What risk level is browser_sessionstorage_set? +

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

Can I rate-limit browser_sessionstorage_set? +

Yes. Add a rate_limit block to the browser_sessionstorage_set 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 browser_sessionstorage_set completely? +

Set action: deny in the PolicyLayer policy for browser_sessionstorage_set. 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 browser_sessionstorage_set? +

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

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