highlight_element · InSite MCP: Risk & Policy

WHAT IT DOES

What highlight_element does on InSite

AI agents invoke highlight_element to trigger actions in InSite. 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 highlight_element needs a policy

Highlighting an element requires executing a browser action (e.g., injecting CSS or JavaScript into the page) to alter its visual appearance. While the effect is transient and non-destructive, it still triggers an external operation on the browser page, placing it in the Execute category. Misuse potential is low since it only affects visual debugging state.

From the tool's definition 'Visually highlight elements on the page' — modifies the visual state of a live browser page by injecting styling or overlays onto elements

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

highlight_element Rate-limited

highlight_element 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": {
    "highlight_element": {
      "limits": [
        {
          "counter": "highlight_element_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 InSite, so you can run agents against it safely.

FAQ

Questions about highlight_element

What does the highlight_element tool do? +

Visually highlight elements on the page for debugging purposes. It is categorised as a Execute tool in the InSite MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on highlight_element? +

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

What risk level is highlight_element? +

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

Can I rate-limit highlight_element? +

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

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

highlight_element is provided by the InSite MCP server (jowharshamshiri/insite). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.