Manually trigger a prune of cached remote audio files older than N days. Default retention is 14 days (7 days on Pi-class hosts). Rate-limited: 2/hour.
AI agents invoke fw_media_prune 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.
This tool executes a scheduled/manual operation that removes data (cached audio files older than N days). While technically destructive in nature (files are deleted), the operation targets cached/temporary files with a clear retention policy rather than primary user data, and it is a standard maintenance operation.
From the tool's definition Tool description states 'Manually trigger a prune of cached remote audio files' — this actively triggers a deletion operation on stored media files based on age criteria.
Documented attack patterns abuse exactly the kind of access fw_media_prune gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Crow, and nothing reaches the server without passing your rules. This is the rule we recommend for fw_media_prune:
{
"version": "1",
"default": "deny",
"tools": {
"fw_media_prune": {
"limits": [
{
"counter": "fw_media_prune_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}fw_media_prune 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.
Free to start. No card required.
Manually trigger a prune of cached remote audio files older than N days. Default retention is 14 days (7 days on Pi-class hosts). Rate-limited: 2/hour. 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.
Register the Crow MCP server in PolicyLayer and add a rule for fw_media_prune: 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.
fw_media_prune is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the fw_media_prune 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.
Set action: deny in the PolicyLayer policy for fw_media_prune. 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.
fw_media_prune 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.
Start from Crow, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
576 Crow tools catalogued and risk-classified — across an index of 43,000+ MCP servers.