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

With no annotations provided, the description carries the full burden. It discloses key behaviors: returns matching books with purchase links, images, and ISBNs; typical exact match returns 9 books across 3 types and 3 difficulty levels; when no exact match exists, returns similarly-named books. This goes beyond basic documentation.

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 5 sentences that efficiently convey purpose, return content, typical results, fallback behavior, and usage scenario. Every sentence adds value; no redundancy. It is well-structured with key information front-loaded.

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 no output schema, the description adequately explains what is returned (links, images, ISBNs) and the structure of results. It covers behavior for exact vs non-exact matches. For a search tool with 2 parameters, this is sufficient, though it does not mention pagination or limits, which are minor gaps.

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 schema already documents both parameters thoroughly. The description adds no extra parameter meaning beyond what the schema provides. Baseline score of 3 is appropriate.

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 tool's purpose: 'Search for personalized puzzle books by first name.' It specifies the action (search), the resource (personalized puzzle books), and the search key (first name). Additionally, it distinguishes from siblings by focusing on name-based search, while 'get_book' likely retrieves a single book and 'suggest_names' provides name suggestions.

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 description provides explicit guidance: 'Use this whenever a user is shopping for a personalized gift and knows the recipient's first name.' This tells the agent when to invoke the tool. It does not explicitly state when not to use it or mention alternatives, but the context of siblings (get_book, suggest_names) implies that for known names this tool is appropriate.

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