espnfantasy_players

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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so the safety profile is covered. The description adds meaningful behavioral details: the default 50-player limit, the role of fantasy_filter in widening/filtering, an example request, and the auth note that a key is not required but a cookie unlocks more. This goes beyond the annotations and does not contradict them.

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 organized into a summary, return shape, example, and auth note, with the primary purpose front-loaded. Each section provides useful information; however, the example JSON and detailed field list make it slightly longer than strictly necessary. Still, there is no wasted repetition, and the structure is clear.

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 supplies the return field list, and the schema covers all parameters. The description fills in the default size, a usage example, and authentication context. It does not discuss pagination or sorting beyond the schema's note about limit requiring sort, but for a list-retrieval tool with this schema and annotations, it is largely complete.

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 description coverage is 100%, so the baseline is 3. The description adds context by explaining the default 50-player limit and positioning fantasy_filter as the widening/filtering mechanism, plus a concrete default example. While the schema's fantasy_filter description is already detailed, the description reinforces the default-limit behavior and provides a quick-start example.

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 clearly identifies the resource as the season's player universe and lists the fields returned, and the Returns section confirms it returns a top-level array. However, it lacks an explicit action verb like 'Get' or 'List', and it does not directly name sibling tools for differentiation, though the phrase 'player universe for a season' distinguishes it from player-specific tools like espnfantasy_player_info.

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 description states the default 50-player limit and says to pass fantasy_filter to widen or filter, which implies when to adjust usage. However, it does not explicitly explain when to use this tool instead of sibling tools such as espnfantasy_rosters or espnfantasy_player_info, nor does it mention exclusions. Usage context is implied but not fully explicit.

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