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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds meaningful behavioral context beyond that: it mentions returning 'verified quote' and 'link to the original source', and that the input can be a name or a slug, which helps set expectations.

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?

The description is three sentences with no wasted words: purpose, usage examples, and input format. It is front-loaded with the main action and reads efficiently.

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?

The description covers what the tool does, when to use it, and how to specify the person. An output schema exists, so return details are handled elsewhere. The only gap is that 'Return every book' is slightly contradicted by the optional limit parameter (default 20), which is not acknowledged in the description.

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 100%, so the baseline is 3. The description repeats the person parameter example ('Naval Ravikant') and the slug form, but this largely duplicates the schema's own description and does not add significant meaning or clarify the limit parameter beyond what the schema already provides.

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?

The description uses a specific verb and resource: 'Return every book a specific person... has recommended'. It also includes concrete query examples ('what books does Naval Ravikant recommend?') that clearly distinguish it from sibling tools like search_books and get_book_recommenders.

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?

Explicit usage guidance is provided with the phrase 'Use this when a user asks...' followed by concrete examples. However, it does not explicitly state when not to use the tool or name alternative tools, so it stops short of full when-not/alternatives coverage.

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