convert_book · Lyceum MCP: Risk & Policy

WHAT IT DOES

What convert_book does on Lyceum

AI agents invoke convert_book to trigger actions in Lyceum. 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 convert_book needs a policy

Converting a book triggers an external operation (format conversion via Calibre content server over HTTP) whose effects depend on arguments. It creates a new format file but does not irreversibly delete data, making Execute the most appropriate category. Severity is medium as misuse could generate unwanted conversions or consume server resources across many books.

From the tool's definition Convert a book to a different format (e.g. EPUB to MOBI). This may take a few minutes.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

convert_book Rate-limited

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

FAQ

Questions about convert_book

What does the convert_book tool do? +

Convert a book to a different format (e.g. EPUB to MOBI). This may take a few minutes. It is categorised as a Execute tool in the Lyceum MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on convert_book? +

Register the Lyceum MCP server in PolicyLayer and add a rule for convert_book: 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 convert_book? +

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

Can I rate-limit convert_book? +

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

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

convert_book 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.