ensure_active_tab

确保存在一个可用且激活的浏览器 tab。如果当前窗口已有 active tab 则直接复用；如果没有任何 tab 但浏览器进程仍在，则新建 tab；如果连窗口都没有，会按 platform 启动 Chrome（macOS: open -a Google Chrome；Linux: xdg-open；Windows: rundll32.exe url.dll,FileProtocolHandler）。本工具不会关 Chrome，不会结束浏览器进程；启动浏览器仅在显式调用本工具时发生。

Server BrowserPilot MCP sept-7-qi/browserpilot-mcp

Category Execute

Risk class High

Parameters 00 required

WHAT IT DOES

What ensure_active_tab does on BrowserPilot MCP

AI agents invoke ensure_active_tab to trigger actions in BrowserPilot 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 IT NEEDS A POLICY

Why ensure_active_tab needs a policy

This tool can trigger external operations including launching a Chrome browser process via platform-specific shell commands (open, xdg-open, rundll32.exe) or creating new browser tabs. These are external side effects that go beyond simple reads or writes, placing it in the Execute category.

From the tool's definition 启动 Chrome（macOS: open -a Google Chrome；Linux: xdg-open；Windows: rundll32.exe url.dll,FileProtocolHandler）...新建 tab；如果连窗口都没有，会按 platform 启动 Chrome

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

ensure_active_tab Rate-limited

ensure_active_tab 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": {
    "ensure_active_tab": {
      "limits": [
        {
          "counter": "ensure_active_tab_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 BrowserPilot MCP, so you can run agents against it safely.

FAQ

Questions about ensure_active_tab

What does the ensure_active_tab tool do? +

How do I enforce a policy on ensure_active_tab? +

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

What risk level is ensure_active_tab? +

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

Can I rate-limit ensure_active_tab? +

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

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

ensure_active_tab is provided by the BrowserPilot MCP server (sept-7-qi/browserpilot-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.