Describe a book

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuine context beyond that: the specific categories of returned data, a 'Readable text:' field explaining whether chapter tools can extract the text (and why not), and the ibooks:// link format. It stops short of describing any limits, but for a read-only lookup this is solid additional value.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the core purpose, then details of the return content, then args. Every sentence contributes, particularly given there is no output schema. The Args section is slightly mechanical but not wasteful.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description carries the full burden of explaining return values, and it does so thoroughly (metadata fields, reading progress, annotation count, readability, link). For a one-parameter read tool nothing essential is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate. It documents the single parameter as 'the book's numeric ID', which clarifies identity but largely restates what the integer type in the schema already conveys. Adequate but minimal.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (describe) and resource (a specific book), then enumerates exactly what the description returns: metadata, reading status, annotation count, text readability, and an Open in Books link. This clearly separates it from list/search siblings like list_all_books and search_books.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The phrase 'Describe a specific book' implies it is used when you already have a book_id and want full detail on one book, but there is no explicit when-to-use, when-not-to-use, or named alternative (e.g., versus search_books or list_all_books). Usage is implied rather than guided.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.