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

With no annotations, the description carries the behavioral burden and does so well: it explains that each entry has a canonical key and human-readable label, and explicitly notes that sensitive full payment details are not returned and instead appear on the confirmation page after booking. It does not describe auth, pagination, or read-only status, but for a simple lookup it covers the important behavioral and privacy traits.

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-load the purpose, then usage guidance, then output and privacy constraints. Each sentence adds distinct information and there is no repetitive or filler wording.

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 one-parameter lookup with no annotations or output schema, the description explains usage, return entry structure, and sensitive-data exclusion. The main remaining gap is that classId's source and format are not 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?

The sole input parameter, classId, has 0% schema description coverage. The description only implies it identifies a class; it does not explain where to obtain the ID, its format, or error behavior, so it fails to compensate for the schema gap.

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 and resource: 'Return the list of payment methods the payee accepts for a class.' That makes the tool's purpose immediately clear and distinct from the sibling search/list tools, none of which deal with class payment methods.

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 explicitly says to use this before calling book_class so the agent can ask the user which payment method to use, including the special case when the payee does not have Stripe enabled. It lacks when-not-to-use conditions and does not mention book_class_as_guest, but the primary usage context is clear.

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