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

Annotations already cover readOnlyHint, idempotentHint and destructiveHint=false, so the no-charge/no-order statement largely corroborates them. The description goes further, though, by disclosing that the total matches what the buyer is actually charged (tiers included) and by explaining the refund condition if the placement is not published or the turnaround is missed — real context an agent cannot get from structured fields.

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?

Four sentences, front-loaded with the pricing outcome and then the side-effect guarantees and checkout flow. Every sentence carries information, though the checkout_url explanation is slightly long for what it conveys.

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 compensates by naming the returned fields (line items, volume discount, final total, checkout_url) and explaining the payment/refund lifecycle. Nothing an agent needs to call this 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% for the single items parameter, including the 'list each outlet once' and 'max 30' constraints, so the schema already carries the semantics. The description adds no parameter-level detail beyond that, making the baseline 3 correct.

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 — prices a set of outlets — and enumerates what comes back (line items, discount, total, checkout_url). It is clear on its own, but never distinguishes itself from the similarly named sibling quote_service, so an agent must infer the split from the noun alone.

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?

Usage is implied rather than stated: the buyer-facing checkout flow and the 'charges nothing and creates no order' note imply this is the pre-purchase pricing step. There is no explicit when-to-use or when-not rule, and no sibling is named as an alternative.

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