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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful content about what the response includes (price, current bid, bid history, buying instructions), but does not address missing-listing behavior, auth requirements, or whether auction fields are absent for non-auctions.

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?

A single front-loaded sentence that communicates the tool's return contents with no wasted words. It is appropriately sized for a simple read tool.

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 read-only one-parameter tool with no output schema, the description gives a reasonable sketch of returned fields. However, it leaves the parameter format unspecified and does not mention error behavior or field applicability (e.g., auction-only fields), which are the remaining gaps.

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 parameter 'listing' has 0% schema description coverage, so the description must compensate. It does not explain whether 'listing' is an ID, slug, or URL, nor any format constraints, leaving the main invocation detail undocumented.

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 resource and scope: retrieving one listing, including price, current bid, bid history for auctions, and buying instructions. The phrase 'One listing' implicitly distinguishes it from listing_search, but it does not explicitly name or contrast that sibling.

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?

There is no explicit guidance on when to use this tool versus listing_search, listing_create, listing_update, or bid_place. The mention of 'how to buy it' loosely implies it is a pre-purchase inspection tool, but no alternatives or exclusions are stated.

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