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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds meaningful behavioral detail beyond annotations: WEEK/MONTH rows read the shared full-marketplace store once populated, and the response carries store=global. This is not derivable from the schema or annotations and helps set expectations about data scope.

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?

The description is two sentences with the main output front-loaded and the scoping nuance second. It is mostly efficient, though phrases like 'shared full-marketplace store once populated' and 'response carries store=global' are slightly dense and could be simplified without losing meaning.

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?

There is no output schema, and the description only summarizes return values as ASINs and click/conversion shares. With six parameters, only one of which has schema-level documentation, the description leaves important call-construction details unclear, such as date formats, filter behavior, pagination semantics, and the role of seller_connection_id.

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 only 33%, and the description does not explain the meaning or usage of limit, offset, week_start_date, search_term_contains, or seller_connection_id. It adds some context about period behavior by distinguishing WEEK/MONTH from DAY rows, but it does not compensate for the low schema coverage across the other parameters.

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?

The description names a specific resource ('marketplace-wide top search terms'), states the output contents ('top-3 clicked ASINs and their click/conversion shares'), and clearly distinguishes its scope from account-filtered alternatives with 'complete term universe, not just this account's filtered slice.' This makes it easy for an agent to recognize what this tool returns and how it differs from sibling search term tools.

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 description provides clear context for when the tool is appropriate: it returns marketplace-wide data from the shared full-marketplace store, especially for WEEK/MONTH periods. It contrasts with 'not just this account's filtered slice,' helping an agent avoid account-level tools, but it does not explicitly name alternative tools or state precise when-not-to-use conditions.

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