How a store is coded

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

With no annotations, the description carries the burden. It does reveal the caveat that certain stores (Walmart/Target, Costco/Sam's) generally won't post category bonuses, which is a behavioral nuance. However, it omits details about error handling, not-found cases, or whether the tool returns partial information, leaving gaps for a tool with zero annotation coverage.

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 two sentences, front-loaded with the core purpose, and adds a useful caveat. It is concise without excessive detail, though the final 'Same ranking the app uses' is slightly redundant but harmless.

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?

The description specifies the main outputs (reward category, merchant type, caveat) but does not address error conditions, duplicate store names, or whether the result is a single match. For a simple lookup with one parameter and no output schema, it is mostly adequate but not fully complete.

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 schema has 0% description coverage and only one parameter 'name'. The description implies that 'name' is the store name (since it starts with 'The store's...'), but it does not explicitly state that the parameter expects a store name or define any format. Given the low coverage, the description should explicitly clarify the parameter semantics, which it only does implicitly.

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 tool looks up a store's reward category, merchant type, and the merchant-code caveat. It is specific about the resource (store/merchant) and the output, and distinct from sibling tools that operate on cards or calendars.

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 given on when to use this tool versus alternatives like 'best_card' or 'search_cards'. The description does not mention prerequisites or disambiguation between similar store names, so the agent has to infer when this lookup is appropriate.

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