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

Annotations only cover the safety profile (readOnly, idempotent, non-destructive); the description adds substantive behavior beyond them: no paging and best-match-first ordering, that an empty list means no match, that alcohol-based drinks are excluded, and that a parameterless call is rejected. These are exactly the traits an agent cannot infer from the annotations.

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-loads purpose, then argument rules, then ranking/refusal behavior, then the sibling pointer. Every sentence carries a distinct fact; nothing is restated from the schema verbatim.

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?

An output schema exists so return structure needn't be described, yet the description still clarifies the meaningful result cases (empty list, rank order). For a 3-param, zero-required search tool, nothing an agent needs to call it correctly 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 coverage is 100%, so the baseline is 3, but the description adds real semantics the schema lacks: how query and product_id interact for ranking, the limit range 1-10 with default 5, and the refusal condition. It does not explain query string syntax beyond examples, so it stops short of a 5.

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 and resource ('find drink and food recipes from the teas.co.uk recipe library') and even scopes the domain with examples (iced teas, lattes, chai, baking). It explicitly separates itself from the sibling find_products, so an agent can route correctly without opening either schema.

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?

Gives the exact argument combinations ('Give query, product_id or both'), the consequence of neither ('the call is refused'), and routes purchasing intent to find_products. When-to-use and when-not-to-use are both explicit.

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