open_tab · PageMap MCP: Risk & Policy

WHAT IT DOES

What open_tab does on PageMap

AI agents invoke open_tab to trigger actions in PageMap. 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 open_tab needs a policy

Given the sibling tools context (browser automation server), 'open_tab' almost certainly opens a new browser tab, which is an external browser operation with side effects. This qualifies as Execute. Severity is medium since opening tabs can trigger navigation to arbitrary URLs, potentially loading malicious content or initiating further actions. Confidence is reduced due to the empty description.

From the tool's definition Tool name 'open_tab' on a server with browser-control sibling tools (close_tab, switch_tab, navigate_back, execute_action, fill_form). Description is empty.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

open_tab Rate-limited

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": {
    "open_tab": {
      "limits": [
        {
          "counter": "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 PageMap, so you can run agents against it safely.

FAQ

Questions about open_tab

What does the open_tab tool do? +

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

How do I enforce a policy on open_tab? +

Register the PageMap MCP server in PolicyLayer and add a rule for 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 PageMap. Nothing to install.

What risk level is open_tab? +

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

Can I rate-limit open_tab? +

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

Set action: deny in the PolicyLayer policy for 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 open_tab? +

open_tab is provided by the PageMap MCP server (oci:docker.io/retio1001/pagemap:0.7.3). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.