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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the bar is lower; the description still adds value by disclosing the document's scope, including rate limits and error semantics, which an agent would not otherwise know. It stops short of stating output format or whether the reference is versioned beyond GET /v1/sold.

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 resource and content list before the usage guidance. The trailing parenthetical about eBay's Marketplace Insights approval and retired findCompletedItems is useful justification but slightly long for its role.

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 carries the burden of describing returns and does so by enumerating the reference's sections. For a zero-parameter, read-only docs tool with full annotation coverage, nothing an agent needs in order to call it correctly is missing.

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 tool takes zero parameters, so the baseline is 4. The description's note that parameters are documented inside the returned reference is consistent and adds a small amount of orientation.

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 concise API reference for the SoldComps API') and enumerates the exact contents (auth, parameters, response fields, median/exclusions, errors, rate limits). The phrase 'reference' and 'writing code' implicitly separates it from data-returning siblings like get_sold_comps and get_pricing, though no sibling is named.

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 a clear triggering condition: use when writing code that fetches eBay sold prices/comps or when asked how to get sold listings programmatically. That condition implicitly excludes direct data retrieval, but there is no explicit 'do not use for X, use get_sold_comps instead' routing.

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