generate_simulation_spec · Moldsim MCP: Risk & Policy

WHAT IT DOES

What generate_simulation_spec does on Moldsim mcp

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

WHY IT NEEDS A POLICY

Why generate_simulation_spec needs a policy

This tool creates new structured data (simulation specifications) from inputs, which is a Write operation. It does not execute simulations or trigger external operations (Execute), nor does it irreversibly delete data (Destructive).

From the tool's definition Tool generates and outputs a structured simulation specification, which represents creation of new data artifacts (analysis types, process conditions, mesh recommendations).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

generate_simulation_spec Rate-limited

generate_simulation_spec 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": {
    "generate_simulation_spec": {
      "limits": [
        {
          "counter": "generate_simulation_spec_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 Moldsim mcp, so you can run agents against it safely.

FAQ

Questions about generate_simulation_spec

What does the generate_simulation_spec tool do? +

Generate a structured simulation specification from a natural language description of the part and requirements. Outputs analysis types, process conditions, mesh recommendations, and expected results. It is categorised as a Write tool in the Moldsim mcp MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on generate_simulation_spec? +

Register the Moldsim MCP server in PolicyLayer and add a rule for generate_simulation_spec: 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 Moldsim mcp. Nothing to install.

What risk level is generate_simulation_spec? +

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

Can I rate-limit generate_simulation_spec? +

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

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

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