browser_start_tracing

What browser_start_tracing does on Playwright MCP

AI agents invoke browser_start_tracing to trigger actions in Playwright MCP. 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 browser_start_tracing is rated High

Tracing is an operational action that initiates monitoring/recording within the browser runtime. While not destructive or financial, it executes a command that triggers external browser instrumentation and affects system state. Classified as Execute rather than Read because it actively initiates a tracing session (an action with side effects) rather than passively retrieving existing data.

From the tool's definition Tool name 'browser_start_tracing' indicates initiation of browser tracing/monitoring. Tracing in browser automation contexts typically triggers recording of network requests, console messages, performance metrics, or other runtime behavior.

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

{
  "version": "1",
  "default": "deny",
  "tools": {
    "browser_start_tracing": {
      "limits": [
        {
          "counter": "browser_start_tracing_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

Questions about browser_start_tracing