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

It discloses state-changing behavior the annotations cannot: the call itself is a no-op preview, it returns a confirmation link, and only the merchant can commit the issuance. It also notes the note field is hidden from shoppers and no email is sent. The only soft spot is mild tension with readOnlyHint=false, since "changes nothing" reads like a read-only preview while the annotation marks the tool as not read-only (plausible if a pending record/link is created).

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 tightly written sentences, front-loaded with the operation and the critical preview caveat. The minor-cost flaw is that the amount-units sentence repeats information already present in the schema.

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?

There is no output schema, so the description must carry the return semantics itself, and it does: it explains that the response is a preview plus a confirmation link. Combined with the 100%-covered input schema and basic annotations, an agent has everything needed to invoke it correctly.

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%, so the baseline is 3. The description largely restates schema content ("Money is integer minor units (cents)" duplicates the amount description), adding little syntactic or semantic detail beyond what the parameters already document.

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 opening sentence states a specific verb and resource ("Issue a gift card") that unambiguously separates it from the only other gift-card sibling, gift_cards_set_status. An agent can identify the operation without opening the schema.

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 explains the surrounding workflow (preview then confirmation link) and the conditional intent of note/recipientEmail, but it never states when to reach for this tool versus alternatives or what prerequisites (e.g., prior merchant setup) apply. Usage is implied rather than directed.

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