find_item_across_retailers

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

Annotations already cover the safety profile (readOnly, non-destructive, open world), yet the description adds real behavioral rules: only compare rows sharing both purchase_type and measurement_unit, treat rows with unavailable_reason as having no confirmed price, and a minimum CLI version requirement. None of that is derivable from the annotations or schema.

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?

Purpose is front-loaded in the first clause and no sentence is filler — each adds a constraint, an alternative, or an interpretation rule. It is dense and leans on em-dash chaining, so it reads as a packed list rather than a structured paragraph, but nothing is wasted.

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?

No output schema exists, and the description compensates by describing the shape of returned rows (purchase_type, measurement_unit, unavailable_reason) and how to interpret an empty set. For a 6-parameter read-only search with full schema coverage, nothing an agent needs 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 3 is the baseline; the description goes beyond by explaining the semantics of empty results and instructing the agent to widen radius rather than concluding non-existence. It reinforces but doesn't add syntax or meaning for lat/lng/query/intent beyond the schema.

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 — comparing ONE grocery/retail item's price across nearby stores — and scopes it against the sibling find_items (search inside one store) and against restaurants. An agent can distinguish it from every sibling without opening a 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?

Explicit trigger ('use when the user asks who has something cheapest'), explicit exclusions ('retail and grocery only, never restaurants'), and an explicit alternative ('to search inside one store already chosen, use find_items'). It also tells the agent what an empty result means and to widen radius before concluding the item doesn't exist.

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