list_family_categories

THE RISK

Low Risk

Why list_family_categories needs a policy

This tool queries and returns information about family categories without modifying, deleting, or executing operations on the model. It is a straightforward data retrieval function analogous to 'list' or 'get' operations, making it a Read category risk with low severity.

From the tool's definition Tool name 'list_family_categories' and description 'Get a list of all family categories in the current Revit model' indicate a retrieval operation with no side effects.

Documented attack patterns abuse exactly the kind of access list_family_categories gives an agent:

POLICY

How to control list_family_categories

PolicyLayer is an MCP gateway — it sits between your AI agents and MCP server for Revit - Python, and nothing reaches the server without passing your rules. This is the rule we recommend for list_family_categories:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "list_family_categories": {}
  }
}

list_family_categories is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register MCP server for Revit - Python — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

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EXPLORE

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FAQ

Questions about list_family_categories

What does the list_family_categories tool do? +

Get a list of all family categories in the current Revit model. It is categorised as a Read tool in the MCP server for Revit - Python MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on list_family_categories? +

Register the MCP server for Revit - Python MCP server in PolicyLayer and add a rule for list_family_categories: 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 MCP server for Revit - Python. Nothing to install.

What risk level is list_family_categories? +

list_family_categories is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit list_family_categories? +

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

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

list_family_categories is provided by the MCP server for Revit - Python MCP server (mcp-servers-for-revit/mcp-server-for-revit-python). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every MCP server for Revit - Python tool call.

Start from MCP server for Revit - Python, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

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