get_available_coupons

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

With no annotations, the description carries full responsibility. 'Fetch' implies a read-only operation, but it does not explicitly state that it does not modify state or any limitations like pagination. The qualifier 'available' suggests only valid coupons, but this is not elaborated.

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 immediately conveys the tool's purpose. Every word earns its place with no wasteful filler.

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 zero-parameter, simple fetch operation, the description is largely sufficient. It clearly states the action and scope. However, the absence of an output schema means it does not hint at the return structure (e.g., array of coupon objects), which would be useful.

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 tool has zero parameters, so the description does not need to explain parameter meanings. The schema coverage is trivially 100%, and the description's focus on 'all available' adds a scope nuance beyond the empty schema.

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 uses a specific verb 'fetch' and a clear resource 'available coupons and discount codes'. It distinguishes itself from sibling tools like apply_coupon and remove_coupon by focusing on retrieval rather than modification.

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 on when to use this tool versus siblings like apply_coupon or get_cart_items. There is no mention of context such as 'use before applying a coupon' or exclusions.

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