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

With no annotations, the description carries the full burden, and it does disclose the critical trait: this is a non-mutating quote ('without buying'), so no order is created. However, it says nothing about auth requirements, rate limits, or what the pricing response actually contains, leaving real behavioral gaps.

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?

A single front-loaded sentence with the core action first and the differentiating qualifier second. No filler or repetition of the tool name.

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 pricing tool with no output schema and no annotations, the description should say more about the returned figure (total, currency, per-unit breakdown). It covers the discount drivers but leaves the response shape unspecified, which is a meaningful gap given nothing else documents it.

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 the baseline is 3; the description earns above that by tying pricing behavior to specific inputs, noting that term and multi-eSIM quantity drive discounts, which the schema descriptions do not state. It adds genuine semantic meaning about how days and quantity affect the quote.

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+resource (price/quote an eSIM order) and the key modifier 'without buying', which immediately distinguishes it from the sibling order_esim. An agent can tell what it does and what it does not do without opening a 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?

'Without buying' clearly frames the use case as pre-purchase price checking, which implies the alternative (order_esim) is the follow-up action once a price is accepted. It stops short of explicitly naming that sibling or stating exclusions, so it is clear context rather than full when/when-not guidance.

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