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

With no annotations, the description carries the behavioral burden and does disclose key return behavior: a merchant checkout link plus checkout_id, and the required follow-up call to report_outcome. However, it does not mention side effects, permissions, idempotency, or error behavior for a purchase-creating operation.

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?

The description is two tight sentences with the primary action and return information front-loaded. Every sentence contributes useful context about the returned checkout_id and the required report_outcome follow-up.

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?

The description covers the core workflow and output identifiers, and an output schema exists, so return values need not be fully restated. Still, for a four-parameter, zero-coverage schema with no annotations, it leaves important parameter and safety details unexplained.

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 0%, so the description must compensate for undocumented parameters. It references a chosen variant, but does not explain product_id, variant_id, quantity, or agent semantics, leaving most parameters without added meaning.

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 clearly states that this tool starts a purchase and creates a checkout, returning a merchant checkout link and Kaupia checkout_id. It distinguishes the later reporting step via report_outcome, though it does not explicitly contrast with search_products or get_product.

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?

It gives clear usage context: start a purchase, keep the checkout_id, and call report_outcome afterward so the order is covered and ranked. It names the follow-up tool explicitly, but does not provide exclusions or guidance against alternative tools for related tasks.

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