assert_element_visible · Visual Annotation MCP

WHAT IT DOES

What assert_element_visible does on Visual Annotation MCP

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

WHY IT NEEDS A POLICY

Why assert_element_visible needs a policy

An AI agent can call assert_element_visible faster than any human can review — one bad instruction and it creates or modifies resources in Visual Annotation MCP by the hundred, each call as confident as the last.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

assert_element_visible Rate-limited

assert_element_visible 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": {
    "assert_element_visible": {
      "limits": [
        {
          "counter": "assert_element_visible_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 Visual Annotation MCP, so you can run agents against it safely.

FAQ

Questions about assert_element_visible

What does the assert_element_visible tool do? +

Assert that an element is visible/actionable. It is categorised as a Write tool in the Visual Annotation MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on assert_element_visible? +

Register the Visual Annotation MCP server in PolicyLayer and add a rule for assert_element_visible: 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 Visual Annotation MCP. Nothing to install.

What risk level is assert_element_visible? +

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

Can I rate-limit assert_element_visible? +

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

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

assert_element_visible is provided by the Visual Annotation MCP server (mstocker1/visual_annotation_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.