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

Annotations already declare readOnlyHint=true, covering safety. The description adds the ranking criterion ('total spending'), which is useful behavioral context, but omits whether ranking is scoped to the date range, how ties are handled, or the return format.

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?

A single, front-loaded sentence with no wasted words. It is appropriately sized for a simple read-only ranking tool.

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 simple, read-only tool with full parameter coverage and no output schema, the description is mostly complete. It omits the fact that results are constrained by the required startDate and endDate, which is a minor gap given the schema already marks them required.

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 three parameters are fully documented (dates and limit) in the schema. The description adds no additional meaning or syntax beyond what the schema provides, so this is the expected baseline.

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 ('Get') and resource ('top merchants') plus the ranking metric ('total spending'). It is distinguishable from most siblings, though it does not explicitly differentiate itself from the similar get_top_products tool.

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?

No when-to-use guidance, no alternatives, and no prerequisites are mentioned. The description only restates the tool's output, leaving the agent to infer that it should be used for merchant ranking.

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