set_opds_settings · Lyceum MCP: Risk & Policy

WHAT IT DOES

What set_opds_settings does on Lyceum

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

WHY IT NEEDS A POLICY

Why set_opds_settings needs a policy

The tool modifies configuration data (enabling/disabling the OPDS catalog and setting credentials) that directly affects how readers authenticate to and access the book library. This is reversible change without permanent destruction, placing it in Write rather than Destructive.

From the tool's definition Tool description states 'Configure OPDS catalog settings' and explicitly mentions setting 'enabled, username, and/or password' — operations that modify authentication and access controls for the OPDS catalog service.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_opds_settings Rate-limited

set_opds_settings 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": {
    "set_opds_settings": {
      "limits": [
        {
          "counter": "set_opds_settings_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 Lyceum, so you can run agents against it safely.

FAQ

Questions about set_opds_settings

What does the set_opds_settings tool do? +

Configure OPDS catalog settings. Set enabled, username, and/or password for OPDS Basic Auth. Reader apps use these credentials to browse and download books. It is categorised as a Write tool in the Lyceum MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on set_opds_settings? +

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

What risk level is set_opds_settings? +

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

Can I rate-limit set_opds_settings? +

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

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

set_opds_settings is provided by the Lyceum MCP server (matthewp/lyceum). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.