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

Annotations already establish the safe read-only, idempotent profile, and the description adds real substance on top: the data source (completed eBay sales), the exact statistic returned (25th percentile to median), the no-match fallback to nearest tracked clubs, and the caveat that prices are not split by condition. It stops short of mentioning freshness guarantees beyond 'the data date' or any rate/coverage limits.

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?

Front-loaded with the trigger condition, then moves to input format and return contents in a logical order with no filler sentences. It is dense — a long single block covering trigger, input, output, fallback, and a caveat — but each clause carries information.

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 two-parameter read tool with an output schema, this covers everything an agent needs: when to call it, how to format the query, what fields come back, what happens on a failed match, and the condition caveat. No ambiguity remains about whether the tool is the right choice for a 'what's it worth' question.

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?

Schema coverage is 100%, so both parameters are already documented, and the description largely restates them: pass the club as the person said it, and condition does not affect pricing. The worked examples ('TaylorMade P790 irons', 'Vokey SM9 56', 'sim2 max driver') add some practical signal about accepted input formats, but the baseline 3 applies when the schema carries the load.

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 names a specific resource and outcome — fair used price range derived from completed eBay sales — which is far more precise than a restatement of the name. It never explicitly contrasts itself with the sibling tools find_used_deals and golf_best_used_under, so the agent must infer that this is a valuation tool rather than a deal-hunting tool.

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?

Opens with an explicit trigger ('Use when someone asks what a used golf club is worth, sells for, or should cost') and even covers the seller-side phrasing ('what should I list it for'). It gives no when-not conditions and does not name the sibling deal-finding tools as alternatives, which leaves routing between valuation and deal search to inference.

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