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

Annotations already cover safety (readOnly, idempotent, non-destructive, openWorld), so the description's added value is the return content: price, MRP, saving, duration, per-month pricing, delivery method, and brand link, plus the 'shortest first' ordering. That is meaningful behavioral detail beyond the annotations, though permission/auth or refresh behavior is unstated.

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 dense sentence, front-loaded with the scope and result set; every clause carries information. Slightly long but no filler.

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 no output schema, the description usefully enumerates the returned fields and ordering, giving an agent enough to call and interpret the tool. Only minor gaps remain, such as currency/locale fallback behavior already partly covered by the country parameter.

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% and both parameters are fully documented in the schema, so the baseline is 3. The description only reinforces that brand and prices are country-store specific and currency-bound, adding no syntax or format detail beyond the schema.

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?

States a specific verb (compare) and resource (plans) scoped to one brand, and enumerates the compared dimensions so the agent knows exactly what 'compare' yields. This clearly distinguishes it from siblings like find_deals, get_fleek_app, and how_fleek_works.

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?

Usage is implied by 'for one brand' — an agent can infer it is the tool for side-by-side plan comparison — but the description never says when to use this over find_deals, nor any prerequisite or exclusion.

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