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

Annotations already cover read-only, idempotent, non-destructive, open-world behavior. The description adds real context beyond them: that players are matched across platforms, that results are ranked by team count, and that a connected profile is required. Return format/ordering nuances are implied but not detailed.

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 the core concept ('YOUR EXPOSURE MAP') followed by definition, then trigger phrases, then the prerequisite. Dense but every clause is useful; the quoted example list is slightly heavy but directly aids retrieval.

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 adequately characterizes the return as a cross-platform ranked exposure list. Combined with annotations covering the safety profile, an agent has enough to select and call it correctly; only response formatting specifics are left to the 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?

Schema coverage is 100% with all three parameters fully documented, so the schema carries parameter meaning. The description reinforces the default behavior ('ALL configured leagues and providers') but adds no syntax or format detail beyond the schema. Baseline 3 applies.

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?

Names a specific resource and scope: 'every player you roster across ALL configured leagues and providers, ranked by how many of your teams hold them.' This cleanly distinguishes it from sibling getters like fantasy_get_my_teams or fantasy_get_rosters, which are per-league/per-team, by emphasizing cross-league aggregation.

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 concrete user-phrasing triggers ('who do I have everywhere', 'players on several of my teams', 'if X gets hurt how many of my teams does it hit') and states the prerequisite 'Needs a connected profile.' It does not explicitly name the sibling alternative to use for single-league rosters, so it stops short of a 5.

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