start_replay_buffer

THE RISK

High Risk

This tool executes a command that initiates a recording subsystem in OBS Studio. While not destructive or financial, it is an Execute action because it triggers an external operation with real-world side effects (consuming system resources, initiating recording).

From the tool's definition Tool description states 'Starts the replay buffer output' — this triggers an external operation (OBS replay buffer activation) whose effects depend on the OBS configuration and system state.

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

HOW TO CONTROL START_REPLAY_BUFFER

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_replay_buffer:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "start_replay_buffer": {
      "limits": [
        {
          "counter": "start_replay_buffer_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

start_replay_buffer 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.

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

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

More OBS MCP Server tools

Destructive obs-remove-input Removes an existing input Destructive obs-remove-profile Removes a profile. If the current profile is chosen, it will change to a different profile Destructive obs-remove-scene Remove a scene from OBS Destructive obs-remove-scene-item Remove a scene item from a scene Destructive obs-remove-source-filter Removes a filter from a source Destructive remove_scene Removes a scene from OBS. Args: scene_name: Name of the scene to remove Destructive remove_scene_item Removes a scene item from a scene. Args: scene_name: Name of the scene th Execute obs-start-output Starts an output

All 200 OBS MCP Server tools →

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Go deeper

High-risk tools in OBS MCP Server → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

What does the start_replay_buffer tool do? +

Starts the replay buffer 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_replay_buffer? +

Register the OBS MCP Server MCP server in PolicyLayer and add a rule for start_replay_buffer: 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_replay_buffer? +

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

Can I rate-limit start_replay_buffer? +

Yes. Add a rate_limit block to the start_replay_buffer 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_replay_buffer completely? +

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

start_replay_buffer 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.

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// WHAT START_REPLAY_BUFFER ON OBS MCP SERVER DOES

// THE RISK

// HOW TO CONTROL START_REPLAY_BUFFER

// EXPLORE