activate_coupon

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

With no annotations at all, the description must carry the behavioral load: it does disclose that this mutates account state and requires an explicit confirm flag, which is the most important thing an agent needs. It omits reversibility, permission/auth requirements, failure modes, and what happens if confirm is left at its default false.

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 short clauses, no filler, and the mutation warning and confirm requirement are front-loaded where an agent will see them before calling. Every word earns its place.

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?

An output schema exists, so the description is not obliged to explain return values, and for a two-parameter mutation the key facts (state change, confirm gate, EAN key) are present. Preconditions and irreversibility of the activation would be the remaining gaps for a state-changing tool with no annotations.

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 the description has to supply the meaning, and it covers both parameters: ean is the lookup identifier for the coupon, and confirm is a required safety gate that must be true. What is missing is format expectations for ean (length, digits) and the explicit consequence of confirm being false rather than absent.

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?

"Activate a Cumulus coupon by EAN" gives a specific verb, resource and lookup key, which clearly separates it from deactivate_coupon and the read-only cumulus_coupon/cumulus_coupons siblings. It does not explicitly name those alternatives, so it stops just short of full sibling differentiation.

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 the use case (activating a coupon you hold) and states the confirm=true prerequisite, which is real guidance. It never says when to prefer this over cumulus_coupon (inspect first) or deactivate_coupon, and gives no preconditions such as whether the coupon must be unexpired or already in the wallet.

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