loadNetlistFromFile

THE RISK

Low Risk

Why loadNetlistFromFile needs a policy

The tool performs a retrieval operation: it reads a netlist file from disk and sets it as the current circuit in LTspice. This is a non-destructive, side-effect-free read action. There is no data modification, deletion, code execution, or financial impact.

From the tool's definition Tool description states 'Load an existing netlist file' — a read operation that retrieves and opens an existing file without modifying or deleting it.

Documented attack patterns abuse exactly the kind of access loadNetlistFromFile gives an agent:

POLICY

How to control loadNetlistFromFile

PolicyLayer is an MCP gateway — it sits between your AI agents and Ltspice, and nothing reaches the server without passing your rules. This is the rule we recommend for loadNetlistFromFile:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "loadNetlistFromFile": {}
  }
}

loadNetlistFromFile is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register Ltspice — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Ltspice tools

Destructive resetToolTelemetry Reset rolling performance telemetry for one tool or all tools. Destructive endLtspiceRenderSession Close the LTspice window associated with a render session. Execute cancelJob Request cancellation for a queued/running job. Execute daemonDoctor Run a daemon/system health check and return actionable recommendations. Execute runMeasAutomation Inject .meas directives into a netlist, run simulation, and parse measurement values. Execute runSimulation Run LTspice in batch mode for the currently loaded netlist. Execute runSweepStudy runSweepStudy Execute runVerificationPlan runVerificationPlan

All 71 Ltspice tools →

Read tools on other servers

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about loadNetlistFromFile

What does the loadNetlistFromFile tool do? +

Load an existing netlist file (.cir/.net/.sp/.spi/.sub/.lib/.txt) as the current circuit. It is categorised as a Read tool in the Ltspice MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on loadNetlistFromFile? +

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

What risk level is loadNetlistFromFile? +

loadNetlistFromFile is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit loadNetlistFromFile? +

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

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

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

Enforce policy on every Ltspice tool call.

Start from Ltspice, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →