update_discount

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

With no annotations provided, the description carries the full behavioral disclosure burden. It adds valuable context beyond the schema: the partial-update semantics and the immutability of code/type/currency after use. It does not cover auth, rate limits, idempotency, or response behavior, but the key gotchas are disclosed.

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 sentences with no filler: the purpose is stated first, followed by the most critical constraint. Every phrase earns its place and important information is front-loaded.

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 tool has 10 parameters and no output schema, yet the description provides only the partial-update behavior and one immutability rule. It does not mention how the target discount is identified beyond what the schema says, nor does it address return values, failure modes, or relationships to sibling tools like set_discount_enabled. The definition is not complete enough for a ten-parameter mutation tool.

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 only 30%, so the description must compensate for the remaining seven parameters. It does clarify that code/type/currency are immutable after use and that the update is partial, but it never explains value, maxUses, minSubtotal, or enabled semantics. The schema itself only documents idOrSlug, startsAt, and endsAt, leaving most parameters semantically opaque.

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 opens with 'Update a discount (partial)', a clear verb and resource pair. The 'partial' qualifier distinguishes it from create_discount and set_discount_enabled, but it does not explicitly name any sibling tool as the alternative, which prevents a 5.

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?

'Only call after the user confirms' provides an explicit condition for invoking the tool, and 'code/type/currency become immutable once the discount has been used' acts as a when-not constraint. The description does not mention alternatives such as set_discount_enabled for toggling a discount's enabled state, so it stops short of full routing guidance.

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