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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety and open-world behavior are covered. The description adds useful source provenance (public store 'about' tab, 'normalized' data) but the field enumeration largely overlaps what the existing output schema provides, so incremental behavioral disclosure is modest.

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 purpose, then the sibling-routing hint. The field list is slightly dense but each item conveys concrete scope, so little 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?

With an output schema present and annotations covering the safety profile, the description does not need to explain return values, and it adequately communicates the data source and scope an agent needs to call it correctly.

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?

The single 'seller' parameter is fully described in the schema (100% coverage, with an example username), so the schema does the heavy lifting. The description adds no format or syntax detail beyond what the schema already states; baseline 3 applies.

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 ('Returns normalized seller about information from the public eBay store about tab') and enumerates the payload (seller stats, top-rated status, location/member-since, store categories). This clearly distinguishes it from ebay_seller, ebay_seller_feedback, and ebay_seller_shop.

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?

Explicitly names an alternative ('Use ebay_seller to get eBay seller profile'), which gives a routing condition. It does not address the other closely related siblings (ebay_seller_feedback, ebay_seller_shop), so coverage is clear but not exhaustive.

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