browser_create_session · Playwright MCP Server MCP

WHAT IT DOES

What browser_create_session does on Playwright MCP Server

AI agents invoke browser_create_session to trigger actions in Playwright MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why browser_create_session needs a policy

Creating a browser session spawns an external browser process, which is an Execute-category action. It triggers an external operation (browser instantiation) whose downstream effects depend on how the session is subsequently used.

From the tool's definition 'Create a new browser session' — launches a browser process and returns a sessionId for subsequent browser automation operations

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

browser_create_session Rate-limited

browser_create_session stays usable, but rate-capped — a runaway agent can't fire it dozens of times 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_create_session": {
      "limits": [
        {
          "counter": "browser_create_session_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Playwright MCP Server, so you can run agents against it safely.

FAQ

Questions about browser_create_session

What does the browser_create_session tool do? +

Create a new browser session. Returns a sessionId that must be used for all subsequent operations. It is categorised as a Execute tool in the Playwright MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on browser_create_session? +

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

browser_create_session is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit browser_create_session? +

Yes. Add a rate_limit block to the browser_create_session 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_create_session completely? +

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

browser_create_session is provided by the Playwright MCP Server MCP server (leviathangk/playwrightmcpforcrawler). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.