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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuine behavioral context beyond that: status semantics (paid = money arrived, settled = seller paid out) and the visibility restriction ("Only the linked account's own checkouts are visible"). It stops short of describing error/empty behavior or rate limits.

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?

Three sentences, front-loaded with the purpose, then the polling guidance, then the visibility constraint. Every sentence adds distinct value with no filler or repetition of the name/title.

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 still explains the shape of the return (status enum, payment request, line items) and what the key statuses mean. Combined with the annotation safety profile, an agent has everything needed to call and interpret it 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 description coverage is 100% for the single intentId parameter, so the schema carries the format and pattern details. The description only implies the link to swop_create_checkout's return value without restating syntax, which meets the baseline 3 when structured fields do the heavy lifting.

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 opens with a specific verb+resource ("Read back a checkout") and explicitly ties it to its sibling creator (swop_create_checkout). It enumerates the returned fields (status, payment request, line items), so an agent knows exactly what this tool yields versus other get_* tools.

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 timing guidance: poll after the buyer has been shown the payment, and it names the lifecycle states that matter (paid vs settled). The alternative direction (use swop_create_checkout to create) is implied rather than stated as a contrast, so it falls just short of the top score.

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