iterate_screen · Mockit MCP: Risk & Policy

WHAT IT DOES

What iterate_screen does on Mockit

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

WHY IT NEEDS A POLICY

Why iterate_screen needs a policy

This tool modifies an existing generated screen/mockup based on feedback, which is a reversible write/update operation. It creates a new or updated version of a UI mockup (PNG + HTML), but does not delete data, execute arbitrary code, or involve financial transactions. Severity is medium because misuse could generate unwanted content or consume API/subscription resources.

From the tool's definition Refine an existing generated screen based on feedback. Use this for follow-up edits

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

iterate_screen Rate-limited

iterate_screen 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": {
    "iterate_screen": {
      "limits": [
        {
          "counter": "iterate_screen_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 Mockit, so you can run agents against it safely.

FAQ

Questions about iterate_screen

What does the iterate_screen tool do? +

Refine an existing generated screen based on feedback. Use this for follow-up edits like. It is categorised as a Write tool in the Mockit MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on iterate_screen? +

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

What risk level is iterate_screen? +

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

Can I rate-limit iterate_screen? +

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

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

iterate_screen is provided by the Mockit MCP server (karyaboyraz/mockit-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.