zemax_set_fields · Zemax MCP: Risk & Policy

WHAT IT DOES

What zemax_set_fields does on Zemax

AI agents use zemax_set_fields 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_set_fields needs a policy

This tool modifies design parameters (field points) in Zemax OpticStudio, which are reversible changes to the optical model. It does not execute arbitrary computations (Execute), delete data (Destructive), involve financial transactions (Financial), or merely read state (Read). The Write category applies because the tool creates or modifies optical design configuration data.

From the tool's definition Tool name 'zemax_set_fields' and description 'Set field points' indicate modification of optical design parameters.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

zemax_set_fields Rate-limited

zemax_set_fields 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_set_fields": {
      "limits": [
        {
          "counter": "zemax_set_fields_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_set_fields

What does the zemax_set_fields tool do? +

Set field points. field_type is 'Angle', 'ObjectHeight', 'ParaxialImageHeight',. 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_set_fields? +

Register the Zemax MCP server in PolicyLayer and add a rule for zemax_set_fields: 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_set_fields? +

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

Can I rate-limit zemax_set_fields? +

Yes. Add a rate_limit block to the zemax_set_fields 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_set_fields completely? +

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

zemax_set_fields 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.