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

Annotations already cover safety (readOnly, idempotent, non-destructive), and the description adds real context: the rating formula, trust weighting by client/signed/verified, the 'best 10' aggregation, and the 'Public' access note. Notably 'Ringout counts in Elo order, verified' and 'Public' disclose source and auth traits beyond the annotations.

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 return shape, but the middle is dense formula notation (·, Σ, pct/perf/W definitions) that is heavier than needed to invoke the tool. It earns some of its length since there is no output schema, but readability suffers.

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 usefully documents the return columns (rank, player, rating, games) and the meaning of rating (0-1000). Access ('Public'), filtering behavior, and rating derivation are all covered, leaving little an agent would miss.

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 baseline is 3, but the description adds meaning beyond the schema: 'kind human|agent keeps only those rows before ranking' clarifies that filtering happens pre-ranking, which is a semantic ordering detail not in the enum description.

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 specific resource and output shape: 'The cross-game agent ranking, best first: rows[{rank, player, rating, games}]'. 'Cross-game' and 'agent' scope it apart from get_leaderboard and get_game, though the distinction is not made explicit.

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 when-to-use guidance and no reference to alternatives like get_leaderboard or get_game. The only routing-like statement is 'kind human|agent keeps only those rows before ranking', which is parameter behavior, not tool selection.

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