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

Annotations already declare readOnly/idempotent/non-destructive, yet the description adds meaningfully more: a per-household per-day search rate limit, the fact that only deals valid today are returned, and the language-dependence of match quality. These are behavioral constraints an agent cannot infer from the structured fields.

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 and scope lead, then return fields, input guidance, validity constraint and rate limit; every sentence carries distinct operational information with no filler or repetition.

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?

With no output schema, the description still enumerates the returned fields (chain, product, deal price, regular price, last valid date) and covers the key constraints (today-only validity, rate limit, language of deal text), leaving nothing an agent needs before calling it.

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 baseline is 3; the description goes further by explaining the intended style of the query parameter (product word, language matching, 'koffie' example) and the reason it materially changes recall. The limit parameter's meaning is left entirely to 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 (Search) and resource (this week's supermarket/drugstore/liquor-store deals) plus scoping (household's own country and selected chains), which clearly separates it from list/pantry siblings. The return fields are named, so the agent knows exactly what comes back.

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 explicit usage context ('meant for cooking and shopping questions, not for listing every deal') and practical input guidance about using a product word in the household's country language. It does not route to a named alternative sibling, but the inclusion/exclusion guidance is clear and actionable.

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