assert_not_visible · Phantom MCP: Risk & Policy

WHAT IT DOES

What assert_not_visible does on Phantom

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

WHY IT NEEDS A POLICY

Why assert_not_visible needs a policy

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

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

assert_not_visible Rate-limited

assert_not_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_not_visible": {
      "limits": [
        {
          "counter": "assert_not_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 Phantom, so you can run agents against it safely.

FAQ

Questions about assert_not_visible

What does the assert_not_visible tool do? +

Vérifie qu. It is categorised as a Write tool in the Phantom 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_not_visible? +

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

What risk level is assert_not_visible? +

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

Can I rate-limit assert_not_visible? +

Yes. Add a rate_limit block to the assert_not_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_not_visible completely? +

Set action: deny in the PolicyLayer policy for assert_not_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_not_visible? +

assert_not_visible is provided by the Phantom MCP server (nthimpulse/phantom-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.