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

The only annotation is destructiveHint=true, so the description carries most of the burden. It usefully discloses the underlying API call (POST /checkouts) and that a shareable url is returned, but it says nothing about authentication, whether checkouts can be reused, or expiry behavior beyond the expires_at param.

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?

Two tight sentences plus a short API line, front-loaded with the operation and scope, then the return value. Nothing is wasted, though the trailing 'API: POST /checkouts' is mildly redundant filler for an agent.

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 seven-param create tool with nested JSON:API objects and no output schema, the description covers the essential question (what comes back: the checkout with its url) and the HTTP operation. It omits any guidance on the nested object shapes, but the schema supplies those.

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 all seven parameters including the nested checkout_data/product_options/checkout_options objects. The description only echoes store + variant and adds no syntax or format detail, so the baseline 3 is appropriate.

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 ('Create a hosted checkout / payment link for a store + variant') and prefixes it with 'WRITE:', making it instantly distinguishable from the read-only list/get siblings. An agent can tell this is the one creation tool in this family 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?

The 'WRITE:' prefix and 'for a store + variant' imply when it applies, but there is no explicit when-to-use/when-not guidance or named alternative. Since no sibling performs a comparable create-checkout action, the omission is less costly, but the description still leaves usage implicit.

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