Intersect and match surfaces across all spaces, setting shared walls as interior boundaries.
AI agents use match_surfaces to create or update resources in Openstudio — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Openstudio environment.
This tool modifies the OpenStudio building model by updating surface properties and boundary conditions—a reversible structural change to the simulation geometry. It does not execute simulations, delete data permanently, or affect financial/external systems.
From the tool's definition Tool description states it will "match surfaces" and set "shared walls as interior boundaries," which modifies the building energy model's geometry and boundary conditions. The verb "match" combined with "setting" indicates persistent changes to model data.
Documented attack patterns abuse exactly the kind of access match_surfaces gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Openstudio, and nothing reaches the server without passing your rules. This is the rule we recommend for match_surfaces:
{
"version": "1",
"default": "deny",
"tools": {
"match_surfaces": {
"limits": [
{
"counter": "match_surfaces_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}match_surfaces 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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Intersect and match surfaces across all spaces, setting shared walls as interior boundaries. It is categorised as a Write tool in the Openstudio MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Openstudio MCP server in PolicyLayer and add a rule for match_surfaces: 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 Openstudio. Nothing to install.
match_surfaces 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 match_surfaces 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 match_surfaces. 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.
match_surfaces is provided by the Openstudio MCP server (natlabrockies/openstudio-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Openstudio, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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146 Openstudio tools catalogued and risk-classified — across an index of 43,000+ MCP servers.