set_scene · Obs MCP: Risk & Policy

WHAT IT DOES

What set_scene does on Obs

AI agents invoke set_scene to trigger actions in Obs. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why set_scene needs a policy

This tool triggers an external operation in OBS Studio by switching the active scene. It's not simply reading data, nor is it creating/modifying stored data in a reversible write sense — it's executing a live state change in a running application. Misuse could disrupt live streams or recordings by switching to an unintended scene, hence medium severity.

From the tool's definition "Switch OBS to a different scene" — triggers an external operation in OBS Studio, changing the active scene state

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_scene Rate-limited

set_scene stays usable, but rate-capped — a runaway agent can't fire it dozens of times 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_scene": {
      "limits": [
        {
          "counter": "set_scene_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-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_scene

What does the set_scene tool do? +

Switch OBS to a different scene. It is categorised as a Execute tool in the Obs MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on set_scene? +

Register the Obs MCP server in PolicyLayer and add a rule for set_scene: 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_scene? +

set_scene is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit set_scene? +

Yes. Add a rate_limit block to the set_scene 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_scene completely? +

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

set_scene 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.