fl_stop

THE RISK

High Risk

Why fl_stop needs a policy

fl_stop executes a command that controls FL Studio's playback state. While the action is reversible (playback can be resumed), it is an Execute category tool because it triggers an external operation with side effects on a running application. Severity is medium because stopping playback disrupts a user's workflow but causes no data loss or irreversible changes.

From the tool's definition Tool description: 'Stop FL Studio playback completely.' The tool triggers an external operation (FL Studio transport control via MIDI) whose effect is immediate and depends on the argument (stop command).

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

POLICY

How to control fl_stop

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

policy.json

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

fl_stop 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 FL Studio 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

Related tools and policies

More FL Studio MCP Server tools

Destructive fl_clear_piano_roll Clear all notes from the FL Studio piano roll. Destructive fl_clear_request_queue Clear any pending note requests without executing them. Destructive fl_delete_notes fl_delete_notes Execute fl_play Start or pause FL Studio playback. Execute fl_trigger_note fl_trigger_note Execute fl_trigger_script Manually trigger FL Studio to process pending note requests. Execute fl_record Toggle recording mode in FL Studio. Write fl_arm_track Toggle the recording arm state of a mixer track.

All 57 FL Studio MCP Server tools →

Execute tools on other servers

Android Forensics ADB MCP Server adb_shell_command EMBA-MCP run_emba_scan Frida Game Hacking MCP remove_breakpoint Procmon request_elevation

Go deeper

High-risk tools in FL Studio 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.
Agent sandbox → Bounding what an agent can execute and where the boundary should sit.
Least privilege for MCP → Granting agents the minimum tool surface the task needs.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about fl_stop

What does the fl_stop tool do? +

Stop FL Studio playback completely. It is categorised as a Execute tool in the FL Studio 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 fl_stop? +

Register the FL Studio MCP Server MCP server in PolicyLayer and add a rule for fl_stop: 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 FL Studio MCP Server. Nothing to install.

What risk level is fl_stop? +

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

Can I rate-limit fl_stop? +

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

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

fl_stop is provided by the FL Studio MCP Server MCP server (karl-andres/fl-studio-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every FL Studio MCP Server tool call.

Start from FL Studio MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →