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

Annotations already establish readOnly, idempotent, non-destructive, so the bar is lower; the description still adds real context (live prices incl. VAT, delivery options per country/parcel, free-delivery gap, basket link) and explicitly states nothing is stored. The 'no basket changes' line partially restates the annotations, but the read-behavior specifics go beyond them.

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-loads the purpose and the pre-basket constraint, then packs return contents and sibling routing into two further sentences with no filler. Every sentence earns its place.

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 pricing tool with full schema coverage and an output schema, the description supplies the routing guidance, the side-effect profile, and the shape of the result. Nothing an agent needs to select or call it 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%, so the schema already documents id, quantity, and country semantics. The description only restates the item shape and the 20-item cap, adding no format or edge-case detail beyond structured data; baseline 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 and resource ('price products') plus the scope ('before anything goes in a basket'), and explicitly distinguishes itself from add_to_basket and checkout_link. An agent can identify the right tool 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 an explicit when ('price for the person before anything goes in a basket'), names the two alternative siblings, and states the condition that selects each ('for a basket the person keeps' vs 'to hand over checkout'). Nothing is left to inference.

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