High Risk →

start_virtual_cam

Starts the virtual camera output.

How to control start_virtual_cam ↓

AI agents invoke start_virtual_cam to trigger actions in OBS MCP Server. 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.

High Risk

Starting a virtual camera is an Execute action because it triggers an external operation (activating OBS virtual camera output) whose actual effects depend on the OBS environment and configuration. While not as severe as destructive operations, it modifies system state and could be misused to enable unauthorized video streaming or create unexpected broadcast behavior.

From the tool's definition Tool name 'start_virtual_cam' and description 'Starts the virtual camera output' indicate activation of a system-level hardware feature (virtual camera). This is an operational action that triggers an external system process with observable side effects.

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

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

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "start_virtual_cam": {
      "limits": [
        {
          "counter": "start_virtual_cam_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

start_virtual_cam 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.

  1. Create a free account and register OBS MCP Server — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
RATE-LIMIT THIS TOOL →

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Go deeper

What does the start_virtual_cam tool do? +

Starts the virtual camera output. It is categorised as a Execute tool in the OBS MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on start_virtual_cam? +

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

What risk level is start_virtual_cam? +

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

Can I rate-limit start_virtual_cam? +

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

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

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

Enforce policy on every OBS MCP Server tool call.

Deterministic rules across all 200 OBS MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.

Free to start. No card required.

200 OBS MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.

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