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

No annotations are provided, so the description carries the full burden. It discloses that renaming the code preserves redemption rows (keyed on coupon id), and that the tool is restricted to operators requiring proof. This provides key behavioral context beyond the schema.

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 three concise sentences, front-loaded with the purpose, then providing usage guidance and a restriction. Every sentence adds value with no waste.

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?

Given the high parameter count (10) and output schema present, the description covers critical aspects: partial update semantics, null-setting via booleans, renaming safety, and access control. It does not detail return values (acceptable due to output schema) but provides sufficient context for agent selection and invocation.

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?

With 0% schema description coverage, the description must compensate. It explains the boolean clear flags and the partial update pattern. However, many parameters like 'name', 'valid_from', and 'discount_percent' are not individually described, relying on self-explanatory names. This is adequate but leaves some ambiguity.

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 'Patch a coupon's editable fields' with a specific verb (patch) and resource (coupon). It distinguishes from sibling tools like delete, mint, or redeem by focusing on updating existing 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?

The description advises to 'pass only the fields you want to change' and explains how to set values to null using boolean flags. It also notes that renaming is safe. However, it does not explicitly state when not to use this tool or list alternatives among siblings.

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