fw_stop_playback

Stop the currently-playing audio stream on the paired glasses and clear any queued tracks. This is a hard stop with no resume. For temporary pause, use fw_pause instead.

SERVERCrow SOURCEkh0pper/crow

High RISK CLASS

Category Execute

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/kh0pper-crow/fw-stop-playback.md

WHAT IT DOES

What fw_stop_playback does on Crow

AI agents invoke fw_stop_playback to trigger actions in Crow. 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.

RISK

Why fw_stop_playback is rated High

This tool triggers an external operation (stopping audio playback on paired hardware) whose effect depends on the current device state. It meets the Execute category definition as it 'runs code, shell commands, browser actions, or triggers external operations.' Severity is medium because stopping audio is a reversible action with limited blast radius—the user can simply resume playback—though it does forcefully…

From the tool's definition Tool description states it 'stop[s] the currently-playing audio stream' and performs a 'hard stop with no resume', indicating active control over an external device (paired glasses) and its media playback state.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs fw_stop_playback safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Crow, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For fw_stop_playback, this is the rule to start with:

fw_stop_playback Rate-limited

fw_stop_playback 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": {
    "fw_stop_playback": {
      "limits": [
        {
          "counter": "fw_stop_playback_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Crow, apply this rule, and every fw_stop_playback call is checked against it from then on.

FAQ

Questions about fw_stop_playback

What does the fw_stop_playback tool do? +

Stop the currently-playing audio stream on the paired glasses and clear any queued tracks. This is a hard stop with no resume. For temporary pause, use fw_pause instead. It is categorised as a Execute tool in the Crow MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on fw_stop_playback? +

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

What risk level is fw_stop_playback? +

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

Can I rate-limit fw_stop_playback? +

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

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

fw_stop_playback is provided by the Crow MCP server (kh0pper/crow). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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