compress · Ffmpeg MCP: Risk & Policy

WHAT IT DOES

What compress does on Ffmpeg

AI agents use compress to create or update resources in Ffmpeg — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Ffmpeg environment.

WHY IT NEEDS A POLICY

Why compress needs a policy

This tool processes and re-encodes video files to reduce their size. It modifies media by creating a compressed version, which is a Write operation (creates/modifies data). While it overwrites the original file potentially, compression is typically reversible in the sense that the original may still exist; however, if it overwrites in place, quality loss from lossy compression is irreversible.

From the tool's definition Compress video to reduce file size using CRF-based H.264/H.265 encoding

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

compress Rate-limited

compress stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "compress": {
      "limits": [
        {
          "counter": "compress_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Ffmpeg, so you can run agents against it safely.

FAQ

Questions about compress

What does the compress tool do? +

Compress video to reduce file size using CRF-based H.264/H.265 encoding. Control quality vs size trade-off. It is categorised as a Write tool in the Ffmpeg MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on compress? +

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

What risk level is compress? +

compress is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit compress? +

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

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

compress is provided by the Ffmpeg MCP server (yuan66-hub/ffmpeg-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.