add_fabric · Clo3d MCP: Risk & Policy

WHAT IT DOES

What add_fabric does on Clo3d

AI agents use add_fabric to create or update resources in Clo3d — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Clo3d environment.

WHY IT NEEDS A POLICY

Why add_fabric needs a policy

The tool creates/adds a new fabric asset to an active design project, which is a reversible modification (fabrics can be removed or replaced). This fits the Write category: it modifies project data without deleting or executing arbitrary code. Severity is medium because incorrect fabric assignments could delay design iteration, but the changes are easily undone and don't affect external systems or destroy data.

From the tool's definition Tool description states 'Add a .zfab fabric to the project' — this is a create operation that modifies the CLO3D project state by introducing a new fabric resource.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_fabric Rate-limited

add_fabric 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": {
    "add_fabric": {
      "limits": [
        {
          "counter": "add_fabric_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 Clo3d, so you can run agents against it safely.

FAQ

Questions about add_fabric

What does the add_fabric tool do? +

Add a .zfab fabric to the project. Returns its fabric index. It is categorised as a Write tool in the Clo3d MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on add_fabric? +

Register the Clo3d MCP server in PolicyLayer and add a rule for add_fabric: 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 Clo3d. Nothing to install.

What risk level is add_fabric? +

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

Can I rate-limit add_fabric? +

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

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

add_fabric is provided by the Clo3d MCP server (lilbonner/clo3d-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.