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

Annotations already declare a safe read (readOnlyHint=true, destructiveHint=false), but the description adds real value beyond them: it discloses that 'paid' is only ever returned after a fresh server-side verification, lists the four possible statuses, and names the required NOMADSTAYS_MCP_AGENT_TOKEN. That auth requirement and the freshness guarantee are not in the annotations or 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?

Three tight sentences, purpose front-loaded, followed by the usage rule and the enumerated statuses plus auth requirement. No filler; every sentence carries information.

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 compensates by enumerating the possible return statuses. The auth dependency is stated and the verification behavior is explained, so an agent has everything needed to call and interpret this tool.

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 single saleId parameter is documented in the schema as 'the saleId returned by purchaseProduct'. The description adds nothing beyond that, 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: 'Check whether a purchase has been paid.' The status enum (pending, paid, failed, waived) further pins down scope. It doesn't explicitly distinguish itself from the similarly-named getBookingStatus sibling, so the differentiation is only implicit in the noun 'purchase' vs 'booking'.

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 a strong when-to-use rule: never trust the member's own claim of payment, always poll this instead. This is actionable guidance an agent can follow. It does not, however, address exclusions or contrast with the getBookingStatus sibling.

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