polish_book

Perform maintenance on a book (EPUB/AZW3) to

SERVERCalibre SOURCE2b3pro/calibre-mcp

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade B, identity unverified Pull the record →

This record as markdown: /tools/2b3pro-calibre-mcp/polish-book.md

WHAT IT DOES

What polish_book does on Calibre

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

RISK

Why polish_book is rated Medium

The tool performs maintenance on ebook files (EPUB/AZW3), which implies modifying existing files. 'Maintenance' operations typically restructure, clean up, or update file contents in-place. This is a Write operation as it modifies existing data, though since the description is cut off we cannot confirm if it has destructive or irreversible aspects. Confidence is reduced due to the truncated description.

From the tool's definition 'Perform maintenance on a book (EPUB/AZW3)' - description is truncated/uninformative beyond indicating it modifies book files

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs polish_book safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Calibre, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For polish_book, this is the rule to start with:

polish_book Rate-limited

polish_book 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": {
    "polish_book": {
      "limits": [
        {
          "counter": "polish_book_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Calibre, apply this rule, and every polish_book call is checked against it from then on.

FAQ

Questions about polish_book

What does the polish_book tool do? +

Perform maintenance on a book (EPUB/AZW3) to. It is categorised as a Write tool in the Calibre MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on polish_book? +

Register the Calibre MCP server in PolicyLayer and add a rule for polish_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 Calibre. Nothing to install.

What risk level is polish_book? +

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

Can I rate-limit polish_book? +

Yes. Add a rate_limit block to the polish_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 polish_book completely? +

Set action: deny in the PolicyLayer policy for polish_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 polish_book? +

polish_book is provided by the Calibre MCP server (2b3pro/calibre-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

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