Coupon Mark Used

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

With no annotations, the description carries the behavioral burden, and it does so well: it discloses that the operation is a toggle, not a setter, that calling again reverses the state, and that the returned item reflects the new state. This is important non-idempotent behavior that an agent must know before invoking the tool.

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 description is three short sentences with no filler. The core action is front-loaded, followed by essential toggle behavior and return-state information. Every sentence contributes value.

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?

The description adequately covers the toggle behavior and response for a simple one-parameter tool, and the output schema handles return-value details. However, it is missing basic contextual details such as the fact that item_id refers to a coupon identifier and any guidance about choosing this tool over coupon_update.

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%, and the description does not explain item_id beyond calling it an 'item.' The description fails to clarify what kind of ID is expected, its format, or how it relates to coupons, leaving the agent to infer the parameter's meaning from the schema alone.

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 clearly states a specific action: toggling the used status of an item, which is distinct from list/get/create/delete operations. However, it does not explicitly distinguish itself from coupon_update, which could also plausibly change a coupon's used status.

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 implies when to use the tool—whenever you need to flip the used status—and explains the effect of repeated calls. It does not, however, provide explicit guidance on when to use this tool versus coupon_update or other siblings, leaving some selection ambiguity.

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