Create one or more surface-based elements in Revit such as floors, ceilings, or roofs. Supports batch creation with detailed parameters including family type ID, boundary lines, thickness, and level information. All units are in millimeters (mm).
AI agents use create_surface_based_element to create or update resources in Revit MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Revit MCP environment.
The tool creates new architectural elements (floors, ceilings, roofs) in a Revit model, which is a write operation that modifies project data. While the changes are technically reversible (elements can be deleted via delete_element or manual undo), the blast radius is medium because incorrect batch creation of multiple surface-based elements could introduce significant modeling errors, affect downstream design…
From the tool's definition Tool name contains 'create' and description states it will 'Create one or more surface-based elements in Revit such as floors, ceilings, or roofs' with 'batch creation' support. This is a reversible modification operation.
Documented attack patterns abuse exactly the kind of access create_surface_based_element gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Revit MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for create_surface_based_element:
{
"version": "1",
"default": "deny",
"tools": {
"create_surface_based_element": {
"limits": [
{
"counter": "create_surface_based_element_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}create_surface_based_element 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.
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Create one or more surface-based elements in Revit such as floors, ceilings, or roofs. Supports batch creation with detailed parameters including family type ID, boundary lines, thickness, and level information. All units are in millimeters (mm). It is categorised as a Write tool in the Revit MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Revit MCP server in PolicyLayer and add a rule for create_surface_based_element: 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 Revit MCP. Nothing to install.
create_surface_based_element is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the create_surface_based_element 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.
Set action: deny in the PolicyLayer policy for create_surface_based_element. 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.
create_surface_based_element is provided by the Revit MCP server (mcp-servers-for-revit/revit-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Revit MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
25 Revit MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.