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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so the bar is lower. The description still adds real context beyond them: prices are USD-normalized, results are facts without ratings, and a 'last checked' freshness signal is returned — meaningful for judging the comparison output.

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?

Two sentences, front-loaded with the core scope and the item cardinality, followed by a short constraint ('Facts only, no ratings'). No filler or redundancy.

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?

An output schema exists, so return structure needn't be spelled out, and the description is sufficient to call the tool correctly with ids and country. The only gap is the undocumented use_case parameter, which leaves one of three inputs semantically opaque.

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 only 33%: country is well documented in the schema, but ids and use_case are not. The description restates the 2-10 id bound and ties the comparison to country coverage, yet adds nothing about how use_case alters the comparison.

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 and resource ('Side-by-side comparison of 2-10 providers') and enumerates the compared facets (coverage, engagement models, prices, HQ, contact routes, shared jobs, last checked). This clearly separates it from single-provider siblings like get_provider and from discovery tools like find_providers.

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 the comparison semantics and the 'Facts only, no ratings' clause signals it is not a recommendation engine, but there is no explicit when-to-use versus get_provider/find_providers guidance and no stated prerequisites such as needing valid provider ids.

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