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

Annotations already cover read-only, idempotent, non-destructive and closed-world, but the description adds information they cannot: results are ordered by vet402's own payment-and-delivery count over a 30-day window, that ordering is explicitly not seller quality, and unpaid listings land in an unordered 'untested' bucket. It also flags seller_description as seller-authored data to be treated as data, a direct prompt-injection guardrail.

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 core behavior and everything after it is substantive. Minor redundancy: the 30-day paid-and-received window is stated twice in consecutive sentences, which could be collapsed without losing meaning.

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?

An output schema exists so return shape needn't be described; the description instead spends its budget on the things structure can't convey — ranking basis, the untested bucket, and the untrusted-data caveat. Nothing needed to call or interpret this tool 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?

Schema description coverage is 100% and both parameters (query, limit) carry their own bounds and meaning in the schema. The description restates the query match surface but adds no syntax, tokenization or limit guidance beyond the schema, so the baseline of 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?

States a specific verb (finds) and resource (x402 listings) plus the exact match surface (URL or description) and the population constraint (listings where vet402 paid and received content in the last 30 days). This is precise enough that an agent can distinguish it from check_x402_seller / check_my_x402_endpoint, which are single-entity checks rather than searches.

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?

Explains the ordering semantics, warns that the order is not a quality ranking, and tells the agent how untested listings are returned — all of which shape how results should be interpreted and used. It stops short of naming a sibling and saying 'use check_x402_seller instead when you already know the seller', which is the only missing piece for a 5.

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