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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive behavior. The description adds non-obvious context: active-listing scope, the devID authentication requirement, and why sold data is unavailable. This goes beyond what annotations alone provide.

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?

Three short, purposeful sentences deliver the action, prerequisite, and key limitation with no filler. The most important information is front-loaded in the first sentence.

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?

Given the rich annotations and fully documented schema, the description covers authentication, listing status, and data limitations effectively. It does not describe return shape or explicitly route to the category-based sibling, but search results are reasonably inferable from the tool name and context.

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?

Input schema covers 100% of parameters with meaningful descriptions, so the baseline is 3. The description's mention of 'by keyword' only repeats the keywords parameter's purpose and does not add parameter-level details about sorting, paging, or limits.

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?

Description clearly identifies a specific verb ('Search'), resource ('active Bonanza marketplace listings'), and method ('by keyword'). The parenthetical endpoint name and the 'No sold data' note further disambiguate it from category-based search siblings.

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 gives clear context: it searches active listings by keyword, requires a Bonanza API devID, and explicitly excludes sold data with a reason. It does not explicitly name sibling bonanza_search_by_category as the alternative, but the keyword/category distinction is clear enough.

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