add_cookies

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/add-cookies.md

WHAT IT DOES

What add_cookies does on Playwright MCP Server

AI agents use add_cookies 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 add_cookies is rated Medium

Adding cookies modifies browser state and can alter authentication tokens, session data, or user preferences. This is reversible (cookies can be cleared), making it Write rather than Destructive. Severity is medium because while an agent could inject malicious session tokens or tracking cookies, the impact is limited to the current browser context and can be undone.

From the tool's definition Tool name 'add_cookies' combined with server context showing Playwright browser automation that enables 'webpage interaction' and state management. Sibling tools include 'clear_cookies' and 'clear_storage', indicating cookie/state manipulation capabilities.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs add_cookies 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 add_cookies, this is the rule to start with:

add_cookies Rate-limited

add_cookies 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": {
    "add_cookies": {
      "limits": [
        {
          "counter": "add_cookies_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 add_cookies call is checked against it from then on.

FAQ

Questions about add_cookies

What does the add_cookies tool do? +

add_cookies 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 add_cookies? +

Register the Playwright MCP Server MCP server in PolicyLayer and add a rule for add_cookies: 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 add_cookies? +

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

Can I rate-limit add_cookies? +

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

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

add_cookies 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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