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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and closed-world scope, so the safety profile is covered. The description adds genuinely useful behavior beyond that: swap fields stay null until an approval/citation exists, and a failed lookup returns the list of valid retailers via the error message.

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?

Three short sentences, front-loaded with the resource definition before the input example and the null/error semantics. The opening is a noun-phrase fragment rather than a verb-led sentence, but there is no wasted text.

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 an output schema present, return-value documentation is not needed, and annotations cover the safety profile. The description closes the two gaps that matter most for a single-param lookup: how to supply the name and how to recover from an invalid one. The one unaddressed gap is that the core concept 'swap' is never defined.

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 0%, so the description must carry the parameter's meaning, and it does supply concrete examples ('Walmart or The Home Depot'). It falls short of specifying exact-name matching, case sensitivity, or whether partial names are accepted, but the examples plus the error-lists-valid-retailers fallback make the parameter usable.

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 names the resource precisely: one retailer's cited financial figures plus any editor-approved swap, and clarifies the singular scope ('One major retailer's'). However, it never differentiates itself from siblings like rate_major_retailers or verified_deals, so an agent must guess whether this or a sibling is the right tool.

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 statement of when to use this tool versus the many 'alternatives'/'deals'/'ratings' siblings. The only routing help is implicit: the input is a retailer name, and the error response lists valid retailers, which is recovery guidance rather than usage guidance.

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