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

Annotations already establish this as a read-only, closed-world operation, so the safety profile is covered. The description adds real behavioral context beyond that: the response can carry ambiguous: true with a candidate list, each call is scoped to exactly one person, numbers reflect 'today', and tracker and wishlist results are distinct parts that both matter. It does not describe the no-match case or what the answer looks like when a person has nothing.

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 core capability is front-loaded in the first sentence, then usage examples, then edge-case handling in a sensible order. It is dense rather than padded, though the closing clause about cards and today's numbers is slightly repetitive of the earlier 'today's numbers' framing.

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 carries the burden of describing returns, and it does so by enumerating status, budget, spending, availability, and who is buying what, plus the ambiguity payload. What remains missing is the empty-result and no-such-person behavior, which matters for a lookup keyed on a free-text name.

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 only 50% — the list parameter is documented but name is not — so the description must compensate, and it largely does. It establishes that name is matched by name and that list narrows to a single gift list when the name appears on more than one, which is meaning beyond what the schema states.

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 gives a specific verb-and-resource statement: it returns one person's gift-tracker entries (status, budget, spending) plus their wishlist across shared groups, including what the signed-in person and others are buying. That is concrete enough to distinguish it from a plain gift-list read, but it never names a sibling such as get_person_gifts, so an agent must infer the boundary from behavior alone.

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 supplies five realistic example phrasings that map directly onto when to call it, and it explains how to handle the multi-match case (ambiguous: true, ask or retry with list) and the multi-person case (one call per person, even for people looked up earlier). It stops short of explicit when-not-to-use guidance or naming an alternative tool for narrower queries.

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