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 real value beyond that by disclosing the conditional return behavior: the gift link appears only once paid, and it is also emailed to the family. It does not say what is returned when unpaid or what happens with an invalid gift_id.

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?

Two sentences, no filler, and the payoff (the booking link) is surfaced immediately after the core status answer. Every clause carries information the agent would otherwise have to guess.

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 single-parameter read tool with no output schema, the description covers the essential return semantics and the workflow position. Minor gaps remain around the unpaid case and failure handling, but nothing blocks a correct call.

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 0%, so gift_id is undocumented in the schema itself. The description partially compensates by implying the id originates from buy_gift_call, but it gives no format, source field name, or error behavior for an unknown id.

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?

"Whether a gift started with buy_gift_call has been paid" states the specific resource (gift) and the exact fact returned (payment state), and it names the sibling that creates the gift so the agent can place it in the workflow. It falls short of a 5 only because the verb is expressed as a question rather than an explicit action.

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?

Mentioning that the gift is "started with buy_gift_call" implies the tool is used after a purchase to poll for payment, which is useful context. There is no explicit statement of when not to use it, no mention of polling cadence, and no reference to the other siblings (get_faq, get_info).

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