add_book_to_library

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

The description adds value beyond annotations by explaining the idempotent upsert behavior in detail and disclosing the required authentication token. Annotations already provide idempotentHint, but the description enriches it with the exact semantics of calling again with a different status. No contradictions.

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 concise, front-loading the core purpose and idempotent behavior, then providing usage guidelines, alternatives, and authentication info. Every sentence adds value, and the structure is logical.

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?

Given the tool's moderate complexity (3 parameters, no output schema), the description covers all necessary aspects: purpose, behavior, when to use, alternatives, and auth requirements. No gaps remain for an agent to invoke the tool correctly.

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 coverage is 100%, so the baseline is 3. The description adds minimal extra meaning beyond the schema (e.g., mentions 'book_id from search_books' and 'Default 'want'' which are already in the schema). Credit for context but no significant enrichment.

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 clearly states the action ('Add a catalog book to the user's library') and specifies the resource. It distinguishes from sibling tools by mentioning alternative update and removal operations, making the purpose unambiguous.

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?

Explicitly states when to use ('put a catalog book...onto a shelf for the first time') and provides clear alternatives: use update_library_book for edits and remove_book_from_library for deletion. This gives the agent precise decision criteria.

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