zemax_open_file · Zemax MCP: Risk & Policy

WHAT IT DOES

What zemax_open_file does on Zemax

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

WHY IT NEEDS A POLICY

Why zemax_open_file needs a policy

Opening a file in OpticStudio loads it as the active design, modifying the application's state. This is a Write operation (changing what file is loaded/active), not merely reading. Misuse could cause loss of unsaved work on the current design, but is generally reversible by reopening the previous file.

From the tool's definition Open a .zmx / .zos lens file (Windows path)

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

zemax_open_file Rate-limited

zemax_open_file 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": {
    "zemax_open_file": {
      "limits": [
        {
          "counter": "zemax_open_file_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 Zemax, so you can run agents against it safely.

FAQ

Questions about zemax_open_file

What does the zemax_open_file tool do? +

Open a .zmx / .zos lens file (Windows path). It is categorised as a Write tool in the Zemax MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on zemax_open_file? +

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

What risk level is zemax_open_file? +

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

Can I rate-limit zemax_open_file? +

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

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

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

// THE FULL RECORD

zemax_open_file is one line of Zemax's registry record.

The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.

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