setSource · Lyngdorf MCP Server MCP: Risk & Policy

WHAT IT DOES

What setSource does on Lyngdorf MCP Server

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

WHY IT NEEDS A POLICY

Why setSource needs a policy

The tool modifies audio device state (input source selection) but the change is reversible—another setSource call can restore the previous state. This qualifies as Write rather than Execute, as it doesn't run arbitrary code or trigger complex external operations.

From the tool's definition Tool name 'setSource' and description 'Set input source' indicate modification of device configuration state.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

setSource Rate-limited

setSource 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": {
    "setSource": {
      "limits": [
        {
          "counter": "setsource_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 Lyngdorf MCP Server, so you can run agents against it safely.

FAQ

Questions about setSource

What does the setSource tool do? +

Set input source. It is categorised as a Write tool in the Lyngdorf MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on setSource? +

Register the Lyngdorf MCP Server MCP server in PolicyLayer and add a rule for setSource: 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 Lyngdorf MCP Server. Nothing to install.

What risk level is setSource? +

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

Can I rate-limit setSource? +

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

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

setSource is provided by the Lyngdorf MCP Server MCP server (thejens/lyngdorf-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.