update_coupon

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

With no annotations, the description carries the full burden of behavioral disclosure. It only states 'partial update,' which is a useful but minimal trait. It does not disclose whether the tool returns the updated coupon, requires specific permissions, handles invalid IDs, or has side effects. For a mutation tool, this is insufficient transparency.

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 a single, concise sentence that states the purpose and key behavior with no wasted words. It is front-loaded and easily scannable.

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?

Despite having a well-described schema, the description lacks critical context for an agent. For a mutation tool with no annotations and no output schema, it should communicate expected return values, error handling, or prerequisites. The description is too sparse to be considered complete for a tool that modifies data.

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?

The input schema provides 100% coverage with descriptions for both parameters. The tool description adds the meaningful context of 'partial update', clarifying that the data object contains only fields to change. This goes slightly beyond the schema's 'Fields to change' wording, which already implies partial updates, but the explicit statement adds clarity.

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 the action: 'Update an existing coupon by id (partial update).' It specifies the resource (coupon), the method (update), and the key behavior (partial update), which distinguishes it from create, delete, or get operations. The parenthetical adds precision without ambiguity.

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 provides no explicit guidance on when to use this tool versus alternatives like create_coupon or delete_coupon. It does not mention any preconditions, exclusions, or scenarios where a different tool would be preferred. The only implicit hint is 'partial update', which suggests it is for modifying existing coupons, but no direct comparison is made.

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