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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds nothing about result volume, pagination, ordering, or what a listing entry contains, so beyond the annotations it contributes little behavioral context.

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 front-loaded sentence with no filler: resource first, then the optional filters. Every clause earns its place.

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?

For a simple three-filter, read-only list tool with no output schema and no nested objects, the description gives enough to call it correctly. Missing pagination/result-limit expectations are the only real gap, and those are low-stakes for a discovery search.

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% — no parameter is documented in the schema — so the description must carry this load, and it does substantially: it clarifies 'race' means a race slug, 'country' accepts either a name or ISO code, and it enumerates the six valid division values. Only the exact race-slug format and country-code casing remain unspecified.

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 (list) and a precisely scoped resource: HYROX athletes looking for sponsors. The qualifying phrase 'looking for sponsors' distinguishes it from get_athlete (single-record lookup) and from search_races, so an agent can route correctly without opening a schema.

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?

The phrase 'optionally filtered by' implies all filters are optional and hints at a discovery use case, but there is no explicit when-to-use guidance, no named alternative (e.g. get_athlete for a known athlete), and no exclusions. Usage is implied rather than stated.

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