close_page · Opera DevTools MCP: Risk & Policy

WHAT IT DOES

What close_page does on Opera DevTools MCP

AI agents use close_page to create or update resources in Opera DevTools MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Opera DevTools MCP environment.

WHY IT NEEDS A POLICY

Why close_page needs a policy

An AI agent can call close_page faster than any human can review — one bad instruction and it creates or modifies resources in Opera DevTools MCP by the hundred, each call as confident as the last.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

close_page Rate-limited

close_page 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": {
    "close_page": {
      "limits": [
        {
          "counter": "close_page_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about close_page

What does the close_page tool do? +

Closes the page by its index. The last open page cannot be closed. It is categorised as a Write tool in the Opera DevTools MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on close_page? +

Register the Opera DevTools MCP server in PolicyLayer and add a rule for close_page: 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 Opera DevTools MCP. Nothing to install.

What risk level is close_page? +

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

Can I rate-limit close_page? +

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

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

close_page is provided by the Opera DevTools MCP server (operasoftware/opera-devtools-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.