browser_cookie_set

A write tool on the Playwright MCP server.

SERVERPlaywright SOURCEhanato238/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/hanato238-playwright-mcp/browser-cookie-set.md

WHAT IT DOES

What browser_cookie_set does on Playwright

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

RISK

Why browser_cookie_set is rated Medium

Setting cookies is a Write operation—it creates or modifies browser state reversibly. However, the severity is elevated to 'medium' rather than 'low' because cookies can contain sensitive authentication tokens, session identifiers, or tracking data. An AI agent could use this to hijack sessions, spoof authentication, or inject malicious cookies.

From the tool's definition Tool name 'browser_cookie_set' indicates setting/writing cookie data. Sibling tools include 'browser_cookie_clear', 'browser_cookie_delete', and 'browser_cookie_get', establishing this as part of a cookie manipulation suite.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs browser_cookie_set safely

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

browser_cookie_set Rate-limited

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

FAQ

Questions about browser_cookie_set

What does the browser_cookie_set tool do? +

browser_cookie_set is a write tool on the Playwright MCP server. It is categorised as a Write tool in the Playwright 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_cookie_set? +

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

What risk level is browser_cookie_set? +

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

Can I rate-limit browser_cookie_set? +

Yes. Add a rate_limit block to the browser_cookie_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_cookie_set completely? +

Set action: deny in the PolicyLayer policy for browser_cookie_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_cookie_set? +

browser_cookie_set is provided by the Playwright MCP server (hanato238/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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