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

Annotations already establish read-only, idempotent, and non-destructive behavior. The description adds a meaningful behavioral prerequisite: it requires a Bonanza API devID, which is not visible in the annotations. This informs the agent about authentication needs.

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 short sentences with no filler. The core action is stated first, followed by the key authentication note, and the external API alias is tucked in parenthetically without disrupting clarity.

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 single-item fetch tool, the description provides the essential action, the required identifier, and an auth prerequisite. The absence of an output schema is mitigated by the fact that the return value is naturally understood as the requested listing, though explicit return/error details would make it fully complete.

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 input schema already documents item_id with 100% coverage, so the baseline is 3. The description rephrases the parameter usage ('by item ID') and hints at an API key requirement, but it does not add new detail about item ID format, constraints, or how the devID is supplied.

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 states a specific action ('Get a single Bonanza listing') and resource ('by item ID'), making its purpose immediately clear. It also distinguishes itself from sibling search tools by emphasizing 'single' and the item ID lookup mechanism.

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 conveys a clear use case: retrieve one listing when you already have its item ID. It does not explicitly compare against bonanza_search or bonanza_search_by_category, but the 'single... by item ID' phrasing provides enough contextual guidance.

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