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

Annotations already establish readOnly, idempotent, non-destructive behavior, and the description stays consistent with them. It adds genuine value beyond the annotations by explaining how to read the results, e.g. 'Higher Elo is better' and that the teams view uses both adjusted and raw Elo.

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?

It is a single dense paragraph that front-loads the primary purpose and then details each view. Nothing is wasted, though the run-on packing of fields into one sentence is slightly harder to scan.

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 carries the return-shape burden and does so adequately for both views. An agent has enough to invoke and interpret the tool; only cross-tool routing and pagination behavior remain 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%, so the baseline is 3, but the description earns extra credit by explaining what the 'teams' view actually contains (adjusted Elo with league strength bonus, raw Elo, peak, games, league), which the terse 'Default matches.' enum description 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 names a specific resource (League of Legends Elo) and spells out the two output modes, matches and teams, along with exactly which fields each returns. An agent can distinguish this from invoke_lol_optimizer, invoke_lol_projections, and invoke_lol_player_pool without inspecting any schema.

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 makes the default explicit ('view matches (default)') and clarifies the purpose of each view, which tells the agent how to choose between them. It stops short of naming when-not-to-use conditions or pointing to a sibling tool for related data.

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