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

Annotations already declare destructiveHint=true, readOnlyHint=false, and openWorldHint=true, so the safety profile is partly covered. The description still adds substantive context beyond that: the effect is forward-looking only and does not retroactively revoke discounts already used, plus the merchant-consent requirement.

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 impact statement is front-loaded and the total length is short. There is mild redundancy between the first two sentences ("Stop a discount code working" / "Stops one discount code working"), but the second sentence still adds the scope detail and the third adds the caution.

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 destructive, id-based operation with no output schema, the description covers the key concerns: what changes, what does not change, and the consent precondition. It omits whether the operation is reversible and any error/authorization behavior, but the annotations carry the destructiveness signal.

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 100% with only two parameters, both documented in the schema (id and optional business). The description adds nothing about parameter semantics, so the baseline of 3 applies.

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 names a specific action (stop a discount code from working) on a specific resource (a discount code), which clearly separates it from sibling tools like agenta_discounts_create, agenta_discounts_list, and agenta_discounts_show. It is clear but does not explicitly name or contrast with those siblings.

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?

"Ask the merchant before calling this" gives an explicit consent prerequisite, and the note that only new purchases are affected while existing subscribers keep their discount defines the effect scope. It stops short of naming an alternative (e.g., re-enabling or editing a code), so it lacks explicit when-not guidance.

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