resize_page · Opera DevTools MCP: Risk & Policy

WHAT IT DOES

What resize_page does on Opera DevTools MCP

AI agents invoke resize_page to trigger actions in Opera DevTools 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 resize_page needs a policy

Resizing a page is a browser-level action with external effect (modifies the viewport/window dimensions). It is not a pure read, nor does it create/modify persistent data, delete anything, or involve finances. It fits Execute as it triggers an external browser operation. Blast radius is low since resizing is easily reversed.

From the tool's definition 'Resizes the selected page' — triggers a browser action that changes the state of an active page/window.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

resize_page Rate-limited

resize_page 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": {
    "resize_page": {
      "limits": [
        {
          "counter": "resize_page_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 Opera DevTools MCP, so you can run agents against it safely.

FAQ

Questions about resize_page

What does the resize_page tool do? +

Resizes the selected page. It is categorised as a Execute tool in the Opera DevTools MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on resize_page? +

Register the Opera DevTools MCP server in PolicyLayer and add a rule for resize_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 resize_page? +

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

Can I rate-limit resize_page? +

Yes. Add a rate_limit block to the resize_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 resize_page completely? +

Set action: deny in the PolicyLayer policy for resize_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 resize_page? +

resize_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.