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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds useful behavioral context by specifying what the tool returns (unit price, quantity constraints, formFields) and its role as a prerequisite for checkout.

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 short sentences with no redundant phrasing. The core purpose is front-loaded, and the usage reminder is placed after the primary definition, making it easy to scan.

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 simple single-parameter read tool, the description is complete: it explains what data is returned, why it matters (checking quantity constraints before payment link), and the parameter is fully documented. An agent has enough information to select and invoke the tool correctly.

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 single productId parameter has a description that cross-references list_products. The tool description adds no additional parameter-level detail, so the baseline 3 is appropriate since the schema already handles the semantics.

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 the tool fetches one product's details (unit price, quantity constraints) and the formFields needed for execution, using a specific verb ('조회합니다'). It also differentiates from sibling list_products by emphasizing single-product detail and checkout-related data.

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?

The description gives explicit usage context: check quantity constraints before creating a payment link. It does not explicitly name alternatives or exclusions, but the 'before payment link' guidance makes the intended scenario clear enough.

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