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

Goes well beyond readOnlyHint=true/destructiveHint=false with real operational facts: archived athletes are absent and unreadable, groups expose a `parent` and already aggregate their sub-groups' athletes so counts must not be summed, and athletes with has_api_access:false must be reported plainly and not planned for. These are exactly the traps an agent would otherwise fall into.

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?

Front-loaded with what is returned and the id formats, then layered with the caveats. It is dense and the group/parent sentence is long, but every sentence carries non-obvious information — nothing is 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?

There is no output schema, yet the description describes the return shape (athlete ids, groups with their athletes and optional `parent`) and the edge cases (archived athletes, has_api_access:false). For a zero-required-parameter read tool, an agent has everything needed to call it and interpret the result.

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 the schema already explains `q`, so baseline is 3; the description adds that matching is case- and accent-insensitive, that it matches athlete OR group names, and that omitting `q` returns the full roster. That is genuine added meaning beyond the schema text.

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 and immediately defines the scope: athletes (usr_…), groups (grp_…), and teams (team_…). It also names the downstream purpose (targeting), so an agent can tell this apart from sibling list tools like list_athlete_subscriptions or list_sports 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?

Gives explicit invocation guidance: 'Pass `q` to filter by name ... bare call = the full roster', and the ids are meant to be cited verbatim rather than guessed. It doesn't name a competing sibling tool or state when-not-to-use, so it stops short of the 5 bar.

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