Create a discount

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

Annotations show readOnlyHint=false and destructiveHint=false, so a write operation is expected. The description adds that it 'returns the created discount,' which is useful return-behavior context. However, it does not disclose side-effect-relevant details such as code uniqueness requirements, store existence prerequisites, or whether an existing discount with the same code is rejected. No contradiction with annotations.

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 short sentences, front-loaded with the core purpose and followed by the most nuanced parameter behavior and then the return value. It contains no filler, though the middle sentence repeats information already present in the schema.

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?

With 11 parameters, no output schema, and minimal annotations, the description plus schema is mostly sufficient. It covers the trickiest value-format semantics and the return value. It omits practical context like code uniqueness, required store existence, or how optional time-related fields behave, leaving the agent to infer some operational constraints.

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 100%, so the input schema documents all 11 parameters. The description's explanation of fixed versus percentage versus free-shipping value semantics largely duplicates the schema's own value parameter description, adding no new parameter-level meaning.

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 states a specific action and resource: 'Create a discount for a store.' This clearly identifies what the tool does. It does not explicitly differentiate from sibling tools like ecommerce_listDiscountsV1, but the create/list distinction is obvious from the verb, and no competing create-discount sibling exists.

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 intended use is implied by the action and store scope, but there is no explicit when-to-use or when-not-to-use guidance, nor any mention of alternatives. For an agent choosing among many ecommerce tools, the description could more directly state when this tool should be selected over list-only or other create tools.

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