list_comparisons

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

With no annotations, the description carries the full behavioral burden. It discloses that the set is small and hand-curated, not an arbitrary-pair engine, and that the output provides pair_key values for get_comparison. It doesn't mention side effects or edge cases, but for a listing tool this is sufficient and adds meaningful context beyond the schema.

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 with zero fluff. The purpose is front-loaded, the example clarifies instantly, and every sentence adds value. It is concise without being under-specified.

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 that an output schema exists (as indicated by context signals), the return format is likely documented elsewhere. The description covers the essential elements: what it lists, valid country values, and how to proceed with get_comparison. It doesn't mention error handling or ordering, but these are minor given the tool's simplicity and the presence of an output schema.

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 coverage is 0% and the only parameter (country) has no enum, only a default. The description explicitly enumerates the valid values ('ireland' or 'united-kingdom'), which is critical information that the schema does not provide. This goes well beyond what the input schema alone conveys, though it doesn't elaborate on the meaning of the parameter beyond its allowed values.

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 uses a specific verb ('List') and a clear resource ('cross-dataset comparison pair'), provides a concrete example, and explicitly contrasts itself with an 'arbitrary-pair engine.' It also names the sibling tool get_comparison for the next step, making its purpose unmistakable.

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?

It clearly states when to use it (to list curated pairs for a country) and instructs passing a returned pair_key to get_comparison for details. It doesn't explicitly exclude other siblings like check_comparability, but the hand-curated vs arbitrary distinction implies a specific role. This is clear context with no exclusions, so a 4 is appropriate.

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