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

Beyond the readOnly/idempotent/non-destructive annotations, it discloses that the call is deterministic, free, requires no payment or account, and that missing steps are explicitly flagged ('documented: false'). That adds auth-needs, cost, and output-honesty context the annotations do not 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?

The purpose is front-loaded and every clause carries signal (payment types, cost fields, payer behavior, call recipe, constraints). It is dense and parenthetical-heavy in places, but for a complex pricing tool the length is justified and non-redundant.

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, the description still sketches the return shape (per-type ordered steps, cost amount/asset/network/USD, call recipe, documented flags) and covers the free/paid and determinism constraints. An agent has enough to decide when and how to call it correctly.

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 baseline is 3, but the description adds real semantic value: it explains that 'payer' is used to select 'the cheapest option you can use' and that 'target: verifier' switches to the verifier's own price/free paths. It largely repeats the object shape already in the schema, keeping it just above baseline rather than at 5.

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 opens with a specific verb and resource ('How a listing is paid for, step by step, and what it costs'), enumerates the payment types returned, and explicitly contrasts itself with a payment action ('It only explains; it never pays'). An agent can distinguish this explanation tool from sibling readers like get_listing or describe_listing 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?

It gives clear invocation context ('Give listing_id, or target 'verifier' for the Agent Output Verifier's live price') and states the tool requires no payment or account. However, it never names or routes to sibling tools (e.g. get_listing for raw listing data), so the when-to-use picture is clear but not fully disambiguated from alternatives.

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