Update coupon

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

With no annotations, the description carries full burden. It mentions `fields にクーポン要素を渡す` (pass coupon element to fields) and `XML IF`, but does not disclose whether it is a full replacement, what happens to existing data, or return format.

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 concise (two clauses) with no fluff, but it is under-specified. While concise, it lacks essential content, making it less effective.

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 mutation tool with no annotations, no output schema, and a nested object parameter, this description is incomplete. It does not explain the XML interface, field structure, operational context, or expected behavior.

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 0% with one `fields` parameter. The description adds only vague guidance (`fields` should contain a coupon element) but fails to define the element's structure or required sub-fields, which is insufficient compensation.

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 `クーポン更新` (update coupon) with a parenthetical `XML IF`, identifying the action and resource. However, it does not distinguish from sibling `rms_patch_coupon`, which also updates coupons.

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?

No guidance is provided about when to use this tool versus alternatives like `rms_patch_coupon`. The description lacks prerequisites, context, or exclusions, leaving the agent to guess.

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