set_volume · Obs MCP: Risk & Policy

WHAT IT DOES

What set_volume does on Obs

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

WHY IT NEEDS A POLICY

Why set_volume needs a policy

This tool modifies audio volume settings in OBS Studio, which is a reversible state change. It falls under Write category rather than Execute because it adjusts a simple parameter rather than triggering complex operations.

From the tool's definition Tool name 'set_volume' with description 'Set the volume of an audio input' indicates modification of audio settings. The parameter range (0.0-1.0, linear mul) confirms this is a reversible configuration change, not retrieval or deletion.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_volume Rate-limited

set_volume 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": {
    "set_volume": {
      "limits": [
        {
          "counter": "set_volume_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 Obs, so you can run agents against it safely.

FAQ

Questions about set_volume

What does the set_volume tool do? +

Set the volume of an audio input (0.0 – 1.0, linear mul). It is categorised as a Write tool in the Obs MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on set_volume? +

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

What risk level is set_volume? +

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

Can I rate-limit set_volume? +

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

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

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