ReturnCheck

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

No annotations exist, so the description carries the full burden, and it does most of it: it discloses the never-invents guarantee (UNKNOWN instead of guessing), that UNKNOWN is free, the 17-of-50 measured success rate, and the payment flow with expiry semantics. It is somewhat silent on latency/timeout behavior and on how confidence scores are derived, which a caller would want for a scraping-dependent tool.

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 on the best-result path and free on the important constraint, and every sentence carries information. It is dense and somewhat repetitive — the page_text recommendation and the 'never invents / UNKNOWN is free' point appear more than once — which costs it a point.

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?

There is no output schema, so the description must describe the return shape, and it does: verdict enum (YES / YES_WITH_CONDITIONS / NO / UNKNOWN), quoted clause, source URL, return window/deadline, fees, and confidence score. Together with the payment-etiquette detail, an agent has everything needed to call and interpret it.

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 67% and the schema already documents the key params (page_text, page_html, payment_signature, dates, country). The description's page_text/page_html guidance largely restates what those schema descriptions say, adding the rationale but little new semantics; unenumerated params like merchant, seller_name, reason, and item_condition are explained nowhere.

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 and resource — 'verifies which return policy actually applies to this purchase' — and names the concrete artifact produced (a policy verdict). An agent knows exactly what this tool answers without opening the 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?

Gives explicit operating guidance: supply page_text/page_html when you already have the page because the server-side fetch only succeeds on about 1 in 3 US retailers, and names the failure population (large retailers and marketplaces). This is a rare, quantified when-it-works/when-it-doesn't statement.

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