iac_mcp_set_property · Iac MCP: Risk & Policy

WHAT IT DOES

What iac_mcp_set_property does on Iac

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

WHY IT NEEDS A POLICY

Why iac_mcp_set_property needs a policy

The tool modifies data and application state through property updates on native macOS applications. While nominally reversible (properties can be set back), the breadth of potential property modifications across all macOS apps (Mail, Finder, Safari, etc.) and the example of state changes creates significant risk if an AI agent misuses it to alter user data, preferences, or application state.

From the tool's definition Tool description states 'Set a property value on a referenced object' and example shows modifying Mail message state ('Mark a Mail message as read'). This performs reversible modifications to application state.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

iac_mcp_set_property Rate-limited

iac_mcp_set_property 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": {
    "iac_mcp_set_property": {
      "limits": [
        {
          "counter": "iac_mcp_set_property_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 Iac, so you can run agents against it safely.

FAQ

Questions about iac_mcp_set_property

What does the iac_mcp_set_property tool do? +

Set a property value on a referenced object. Usage: 1. First obtain a reference using query_object 2. Call set_property with the reference ID, property name, and new value 3. The property will be updated on the target object Examples: Mark a Mail message as read: - reference:. It is categorised as a Write tool in the Iac MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on iac_mcp_set_property? +

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

What risk level is iac_mcp_set_property? +

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

Can I rate-limit iac_mcp_set_property? +

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

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

iac_mcp_set_property is provided by the Iac MCP server (jsavin/iac-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.