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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so they carry little weight here. The description adds genuinely new behavior: results are paginated in site rank order, which tells the agent that offset windows are stable and ordered by rank rather than by name or id.

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?

Three short sentences, zero filler, with the payload description front-loaded and the caveat about role immediately after. Nothing could be removed without losing information.

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 must carry the return-value burden, and it does so only at a high level (tiers plus win/pick rates). Combined with 0% schema coverage on five parameters, an agent can call it but still does not know the shape of tier values or the record structure.

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 0% across five parameters, so the description must compensate. It does resolve the most error-prone one — role takes champion class tags (Fighter, Tank, Mage) rather than lane positions, which matches the enum and prevents a likely misuse. tier, limit, offset, and locale remain unexplained, though limit/offset/locale are largely self-evident from defaults and bounds.

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 concrete resource and payload: champion tiers plus public win/pick rates, which is specific enough to separate it from get_champion_build or get_top_combos. It stops short of explicitly naming how it differs from those siblings, so it lands just below the top.

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?

There is no statement of when to choose this tool over get_champion_build, get_top_combos, or search, and no prerequisites or exclusions. The only guidance-like sentence concerns how to interpret the role filter, which is parameter clarification rather than usage routing.

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