refresh_library · Plex MCP: Risk & Policy

WHAT IT DOES

What refresh_library does on PlexMCP

AI agents invoke refresh_library to trigger actions in PlexMCP. 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 refresh_library needs a policy

Refreshing library metadata triggers an external operation on the Plex Media Server — it scans/re-fetches metadata for an entire library. This is not a simple read, nor does it irreversibly delete data, but it does execute an action with side effects (metadata updates, network calls to metadata agents, potential overwrites of existing metadata).

From the tool's definition Refresh metadata for a library

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

refresh_library Rate-limited

refresh_library 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": {
    "refresh_library": {
      "limits": [
        {
          "counter": "refresh_library_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 PlexMCP, so you can run agents against it safely.

FAQ

Questions about refresh_library

What does the refresh_library tool do? +

Refresh metadata for a library. It is categorised as a Execute tool in the PlexMCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on refresh_library? +

Register the Plex MCP server in PolicyLayer and add a rule for refresh_library: 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 PlexMCP. Nothing to install.

What risk level is refresh_library? +

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

Can I rate-limit refresh_library? +

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

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

refresh_library is provided by the Plex MCP server (sandraschi/plexmcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.