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

Annotations declare readOnlyHint=true, but the description reveals a side effect: 'triggers order fulfillment.' This directly contradicts the read-only annotation, making the behavioral profile inconsistent. The description does add valuable context (polling, auth, side effect), but the contradiction forces a score of 1 per the rubric.

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 concise and front-loaded, with the purpose stated first, then usage, side effect, polling interval, and auth requirement. Every sentence adds value without fluff.

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 status-check tool, the description covers all necessary context: what it checks, when to use it, the side effect (triggering fulfillment), polling recommendations, and authentication. An output schema exists, so return format need not be described.

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 both parameters have descriptive titles/schema descriptions. The tool description adds no extra meaning about parameters beyond mentioning checkout_id implicitly and authentication, which is already in the schema. 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?

The description states a clear verb and resource: 'Check the payment status of a checkout session.' It also distinguishes this from siblings by referencing checkout_create and the payment_url, making it unambiguous that this is the polling tool for payment status.

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 explicitly says when to use it: 'Use this to poll for completion after sending the patient a payment link.' It also gives a polling interval. However, it does not mention alternatives like auth_check_payment or when not to use it, so it lacks explicit exclusions.

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