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

Annotations already declare readOnlyHint=true and openWorldHint=false, but the description adds substantial context beyond them: the available:false semantics for off-sale skus, the no-retry rule, the meaning of checkout_note with the 4% conversion fee, and the fact that url is the only purchase location. That is meaningfully more than the annotations convey.

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 with the verb, resource, and return fields, then constraints. The checkout_note sentence is somewhat dense and quotes a long string, but each clause carries operational information rather than filler.

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 carries the burden of describing returns and does so (name, type, language, list price, currency, url, available, checkout_note). Combined with the read-only guarantee, an agent has everything needed to call and interpret the tool.

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% and the schema already describes the single sku parameter with an example. The description only reinforces that the sku comes from list_products, adding little beyond the structured field, so the 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 ('Get one Nema by Anahana product by its sku'), names the source of the identifier (list_products), and enumerates the returned fields, so it is clearly distinguishable from list_products and the other content siblings.

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?

Explicitly tells the agent where the sku comes from (list_products) and gives a when-not rule ('a sku that is in the catalog but not on sale returns available: false ... do not retry it'). It does not name alternative siblings for non-product lookups, so it falls short of full alternative routing.

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