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

Annotations only supply readOnlyHint/openWorldHint; the description adds the auth requirement ('needs your API key'), a privacy guarantee ('never its wallet'), an edge case with side effects (shared-human buyer can be rated but counts 0 with reason), and untrusted-field marking ('_untrusted'). Far beyond what the annotations carry.

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-loads purpose and ordering before enumerating return fields and routing, and nearly every clause carries unique information (review_status values, recordPurchase path, shared-human rule). It is a single very dense run-on, though, which costs some readability.

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 and only one trivial parameter, the description carries the return-value burden and does so thoroughly: transaction hash, amount, review_status values, mine/theirs semantics, purchase_id handoff, and seller attribution. Nothing needed 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?

Only one parameter (limit) and schema description coverage is 100%, with the schema already stating the default, min/max and 'Newest first'. The description repeats the ordering but adds no syntax or range detail, so the baseline 3 applies.

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?

Opens with a concrete verb+resource ('What you sold'), specifies ordering ('newest first') and the exact population ('each verified or pending purchase of your listings'). This cleanly separates it from the sibling myPurchases (buying) without needing to open either schema.

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?

Names the follow-up route explicitly ('Use the `purchase_id` with review()') and the alternative path ('seller-run links need recordPurchase'), plus the no-action case ('Sales on hosted listings appear here without any call from you'). When-to-use and what-to-use-instead are both spelled out.

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