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

The annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, destructiveHint=false, and the description is consistent with them, so no contradiction. Beyond that, the description adds the prerequisite that it "needs a connected profile" and explains that it returns data "matched across platforms" – extra context an agent needs to set expectations. This is useful, though it doesn't mention rate limits or caching, which are not critical here.

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, front-loaded with the core purpose ("YOUR EXPOSURE MAP: ..."), followed immediately by concrete example queries. There is no filler or redundant commentary; every clause adds value to the agent's understanding.

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 zero-required-parameter, read-only retrieval tool with no output schema, the description covers the essential contract: what it returns (players ranked by how many teams hold them), the prerequisite (connected profile), and the intended use cases. It doesn't describe the exact shape of the ranked output, but given the rich schema for response format and the lack of output schema, this is acceptable. A slightly higher score would risk over-crediting a description that optionally already has schema to lean on.

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 each parameter (sport, provider, response_format) is already documented with type, default, and examples. The description does not add any parameter-specific nuance; it references the broad absence of filters ("ALL configured leagues and providers") but doesn't elaborate on how the optional filters modify the result. The baseline 3 is appropriate since the schema handles parameter semantics.

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 is concrete: "every player you roster across ALL configured leagues and providers, ranked by how many of your teams hold them." It names the specific resource (the user's exposure map) and clearly differentiates from sibling tools like fantasy_get_my_team and fantasy_get_my_teams by its cross-league, cross-provider scope. The verb and intended output are unambiguous.

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 provides clear user intents with quoted use cases ("who do I have everywhere", "my exposure"), which helps an agent map natural-language requests to this tool. It doesn't explicitly say 'don't use for single league or team', but the phrase "ALL configured leagues and providers" and the title's "exposure across every league" communicate the distinct context versus more focused roster tools.

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