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

Annotations already declare readOnlyHint/openWorldHint/destructiveHint, so the bar is lower, and the description still adds operational context that annotations do not: parallel-safety and upstream cost of 1. It also clarifies that the output shape shifts with the league, which is genuine behavioral disclosure.

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 resource, then per-league behavior, then operational metadata and an example. Slight redundancy: the example payload is duplicated from the schema, and "Champions and rankings" is partially restated in the BKFC/RAF sentences.

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?

An output schema exists so return values need no explaining, and the description covers both enum values, the optional parameter's effect, an example call, and cost/safety. Nothing essential for a correct invocation is missing, though error or empty-result behavior is unaddressed.

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 an enum and example on league, so the schema baseline is 3. The description earns above baseline by explaining what division actually does differently per league, including the "no ranked lists" case for RAF, which the schema does not convey.

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 states a specific resource (champions and rankings) and splits it precisely by league: RAF title holders vs BKFC official rankings + champions. It is enough to tell what the tool returns, though it never names a sibling tool it should be chosen over.

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?

It gives concrete when-to-use guidance for the division parameter per league (omit for every BKFC division's ranked list, pass one like "heavyweight"; RAF has no ranked lists and returns all titles or one division's detail). It stops short of naming alternatives or exclusions, so it is strong context rather than full routing.

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