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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds the scope that the result includes point-spend configuration alongside discount codes, which is useful context beyond the annotations. It does not disclose pagination, auth requirements, or return shape, so it adds value but not rich behavioral detail.

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?

A single sentence with zero waste, front-loading the main resource and appending the secondary point-spend dimension. Every phrase earns its place.

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 a simple read-only list tool with one fully documented optional parameter and no output schema, the description is nearly complete. The only gaps are return format and pagination behavior, which are minor for a list operation whose safety is covered by annotations.

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 100%; the token_address parameter is fully documented in the schema, including the 'omit to list every linked store' semantics. The description adds no parameter-level detail beyond the schema, so the baseline 3 applies.

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 verb (list) and resource (discount codes) and adds the secondary resource of point-spend methods (online code, register voucher, both). It is clear what the tool returns, but it doesn't differentiate itself from siblings like update_store_discount_code or list_rewards, so it falls short of a 5.

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?

There is no explicit guidance on when to use this tool versus alternatives. The sibling update_store_discount_code is the mutation counterpart, and list_rewards covers a different resource; the agent must infer the boundary. The only condition implied is 'for this merchant's Shopify store,' which is context, not usage direction.

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