top_selling_items

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

readOnlyHint=true already establishes this is a safe read, so the description only needs to add behavioral context. It discloses the ranking dimension, which is useful, but says nothing about how period interacts with from/to (mutually exclusive? precedence?), what happens when no date parameters are supplied despite zero required params, or the default period behavior.

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?

Two sentences, front-loaded with the core action and ranking modes, followed by a one-line example that grounds the use case. No redundant or filler text.

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?

For a six-parameter, zero-required tool with no output schema, the description omits the most consequential behavioral detail: how period and the explicit from/to range combine, and what the tool returns when the caller supplies neither. Adequate but with a clear gap.

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 all six parameters are self-documenting; the baseline of 3 applies. The description's ranking clause only restates the metric enum values and adds no syntax or interplay detail 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 ('Get the top-selling items'), plus the two ranking modes ('by quantity sold or by sales amount'). The resource is clearly distinct from the sibling top_employees_by_sales, and the example question ('What was the best-selling dish today?') pins the intent 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?

The question-style example ('What was the best-selling dish today?') implies the intended usage scenario, but there is no explicit when-to-use guidance, no mention of when this is preferable to sales_summary, and no exclusions or prerequisites.

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