previous_chapter · MCP Media Server MCP: Risk & Policy

WHAT IT DOES

What previous_chapter does on MCP Media Server

AI agents invoke previous_chapter to trigger actions in MCP Media Server. 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.

WHY IT NEEDS A POLICY

Why previous_chapter needs a policy

This tool executes a playback control command with external side effects (modifying the current playback position in a media player). While not destructive or financial, it is an Execute-category action because it triggers an external operation (media player seek) whose effects depend on the current video state.

From the tool's definition The tool 'previous_chapter' performs a media control action that invokes the system's media player to seek to a previous chapter location. The verb 'jump' indicates an active operation on playback state.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

previous_chapter Rate-limited

previous_chapter 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": {
    "previous_chapter": {
      "limits": [
        {
          "counter": "previous_chapter_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about previous_chapter

What does the previous_chapter tool do? +

Jump to the previous chapter or scene in the video. It is categorised as a Execute tool in the MCP Media 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 previous_chapter? +

Register the MCP Media Server MCP server in PolicyLayer and add a rule for previous_chapter: 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 MCP Media Server. Nothing to install.

What risk level is previous_chapter? +

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

Can I rate-limit previous_chapter? +

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

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

previous_chapter is provided by the MCP Media Server MCP server (neal3000/mcp_media_server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.