chrome_open_tab · Nextjs Agent MCP: Risk & Policy

WHAT IT DOES

What chrome_open_tab does on Nextjs Agent

AI agents invoke chrome_open_tab to trigger actions in Nextjs Agent. 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 chrome_open_tab needs a policy

This tool executes a real browser action by opening a new tab, which constitutes an external operation. While not destructive or financial, it can be misused to navigate to arbitrary URLs, trigger downloads, or initiate other browser-based side effects, making it an Execute-category tool with medium severity.

From the tool's definition 'Open a new real browser tab at' — triggers an external browser operation (opening a tab) whose effects depend on the URL argument

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

chrome_open_tab Rate-limited

chrome_open_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": {
    "chrome_open_tab": {
      "limits": [
        {
          "counter": "chrome_open_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 Nextjs Agent, so you can run agents against it safely.

FAQ

Questions about chrome_open_tab

What does the chrome_open_tab tool do? +

Open a new real browser tab at. It is categorised as a Execute tool in the Nextjs Agent MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on chrome_open_tab? +

Register the Nextjs Agent MCP server in PolicyLayer and add a rule for chrome_open_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 Nextjs Agent. Nothing to install.

What risk level is chrome_open_tab? +

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

Can I rate-limit chrome_open_tab? +

Yes. Add a rate_limit block to the chrome_open_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 chrome_open_tab completely? +

Set action: deny in the PolicyLayer policy for chrome_open_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 chrome_open_tab? +

chrome_open_tab is provided by the Nextjs Agent MCP server (zohaib3249/nextjs-agent-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.