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

Annotations already declare readOnly, idempotent and non-destructive; the description goes well beyond them by decoding each status value, warning never to pay again during pending, explaining that paid_no_order means funds landed as balance but no order was placed, and noting polling is safe. That is real operational context an agent cannot infer from the schema.

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?

Front-loads the core action and payload, then adds the polling loop and the two ambiguous status meanings. Dense and every sentence carries information, though the status enumeration could be trimmed slightly without losing meaning.

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?

There is no output schema, so the description correctly carries the burden of describing return values: the status set, the frozen quote, and post-payment payment/order/tracking data. Nothing an agent needs to call and interpret this tool is missing.

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% and the token parameter is already fully documented there, including its bearer/security semantics. The description adds no syntax or format detail beyond the schema, so the baseline 3 applies.

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 ('Read a checkout session created with create_checkout') and enumerates exactly what it returns: status, frozen quote, and once paid the payment and order with tracking code. This clearly separates it from create_checkout and get_paid_order_status without opening either 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?

Gives explicit operational guidance: poll after handing over the link, every few seconds, until it reports paid or expired, plus what to tell the person for pending and paid_no_order. It does not name a sibling alternative (e.g. get_paid_order_status) for the paid-after-the-fact case, so it falls just short of the top rung.

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