add_library · Plex MCP: Risk & Policy

WHAT IT DOES

What add_library does on PlexMCP

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

WHY IT NEEDS A POLICY

Why add_library needs a policy

Adding a library is a Write operation because it creates a new configuration/resource in the Plex system. While it modifies the media server state, it is reversible (the library can be deleted). This is not Destructive since library addition doesn't irreversibly delete data. It's not Execute because it doesn't run arbitrary code or commands.

From the tool's definition Tool name 'add_library' and description 'Add a new library' indicate creation of a new library resource in Plex Media Server. This is a reversible modification operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_library Rate-limited

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

FAQ

Questions about add_library

What does the add_library tool do? +

Add a new library. It is categorised as a Write tool in the PlexMCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on add_library? +

Register the Plex MCP server in PolicyLayer and add a rule for add_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 add_library? +

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

Can I rate-limit add_library? +

Yes. Add a rate_limit block to the add_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 add_library completely? +

Set action: deny in the PolicyLayer policy for add_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 add_library? +

add_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.