bulc_modify_mesh · BULC Building Designer MCP: Risk & Policy

WHAT IT DOES

What bulc_modify_mesh does on BULC Building Designer

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

WHY IT NEEDS A POLICY

Why bulc_modify_mesh needs a policy

The tool modifies existing mesh configuration (dimensions, cell counts, properties) but does not permanently delete or destroy data. Changes to mesh parameters in a simulation can typically be undone via the undo/redo support mentioned in the server description. This is a Write operation rather than Destructive.

From the tool's definition Tool name 'bulc_modify_mesh' and description 'Modify an existing FDS mesh. Change dimensions, cell counts, or other properties.' indicate reversible modification of mesh properties in a fire simulation model.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

bulc_modify_mesh Rate-limited

bulc_modify_mesh 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": {
    "bulc_modify_mesh": {
      "limits": [
        {
          "counter": "bulc_modify_mesh_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 BULC Building Designer, so you can run agents against it safely.

FAQ

Questions about bulc_modify_mesh

What does the bulc_modify_mesh tool do? +

Modify an existing FDS mesh. Change dimensions, cell counts, or other properties. It is categorised as a Write tool in the BULC Building Designer MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on bulc_modify_mesh? +

Register the BULC Building Designer MCP server in PolicyLayer and add a rule for bulc_modify_mesh: 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 BULC Building Designer. Nothing to install.

What risk level is bulc_modify_mesh? +

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

Can I rate-limit bulc_modify_mesh? +

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

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

bulc_modify_mesh is provided by the BULC Building Designer MCP server (using76/bulc_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.