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

The annotations only declare readOnlyHint=true, and the description repeats 'Read-only' (no added credit) but goes further by disclosing the actual pricing model — per-item first/each-extra rates for tee, hoodie and sticker sheet. That is genuine behavioral detail an agent needs to interpret the quote; it stops short of covering size upcharges, the 10-item cap, or the response shape.

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?

Extremely dense: one sentence for the return/scope, one for the safety hint, and a compact rate table. Nothing is wasted, though the opening fragment omits a verb, making it slightly telegraphic.

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?

For a read-only quote tool with no output schema, the description does state the three returned values and the pricing rules, which covers the core. It omits currency, how multi-item baskets are aggregated, and the US-only constraint on the country parameter, leaving real gaps.

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 reported at 0%, so the description must carry the load, and it does not. It never explains the items array, that product_id and quantity are required, that size/color are required for tees and hoodies, or why country is a US-only enum — the per-product rates only loosely hint at valid product types.

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 names the concrete outputs (subtotal, shipping, total) and the scope (US delivery), which is enough to separate it from get_product, search_products and create_checkout_link. It lacks an explicit verb such as 'calculate', but the resource and result are unambiguous.

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 only implied: the US-only framing and price table suggest this is called to cost an order before checkout, but no sibling is named and there is no statement of when to prefer this over create_checkout_link or when not to call it (e.g. non-US orders).

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