cfd_run_solver · FreeCAD MCP: Risk & Policy

WHAT IT DOES

What cfd_run_solver does on FreeCAD MCP

AI agents invoke cfd_run_solver to trigger actions in FreeCAD MCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why cfd_run_solver needs a policy

This tool executes an external computational process (CFD solver) whose effects depend on the simulation parameters and case setup. CFD solvers can be computationally intensive and may generate large outputs or temporary files.

From the tool's definition Tool name 'cfd_run_solver' indicates execution of a computational fluid dynamics solver. The server description mentions 'fluid simulation' as a capability.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

cfd_run_solver Rate-limited

cfd_run_solver stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "cfd_run_solver": {
      "limits": [
        {
          "counter": "cfd_run_solver_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches FreeCAD MCP, so you can run agents against it safely.

FAQ

Questions about cfd_run_solver

What does the cfd_run_solver tool do? +

cfd_run_solver. It is categorised as a Execute tool in the FreeCAD MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on cfd_run_solver? +

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

What risk level is cfd_run_solver? +

cfd_run_solver is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit cfd_run_solver? +

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

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

cfd_run_solver is provided by the FreeCAD MCP server (sandraschi/freecad-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.