dom_append_html · Claude Imagine MCP: Risk & Policy

WHAT IT DOES

What dom_append_html does on Claude Imagine

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

WHY IT NEEDS A POLICY

Why dom_append_html needs a policy

This tool writes new HTML content into the browser DOM by appending to an existing element. It is reversible in principle (content can be removed), so it falls under Write rather than Destructive. Misuse could inject malicious scripts or UI elements (XSS risk), warranting medium severity.

From the tool's definition 'Append HTML content to an element' - creates/adds new content to existing DOM elements

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

dom_append_html Rate-limited

dom_append_html 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": {
    "dom_append_html": {
      "limits": [
        {
          "counter": "dom_append_html_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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

FAQ

Questions about dom_append_html

What does the dom_append_html tool do? +

Append HTML content to an element. It is categorised as a Write tool in the Claude Imagine MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on dom_append_html? +

Register the Claude Imagine MCP server in PolicyLayer and add a rule for dom_append_html: 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 Claude Imagine. Nothing to install.

What risk level is dom_append_html? +

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

Can I rate-limit dom_append_html? +

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

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

dom_append_html is provided by the Claude Imagine MCP server (t3rm1nu55/claudeimagine). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.