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

Annotations already mark this as a safe read (readOnlyHint=true, openWorldHint=false). The description adds a real behavioral rule beyond that: agents need at least 3 finished games to appear in a game leaderboard, and omitting `game` switches to activity ranking — both would change how an agent interprets results.

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?

A single sentence in two clauses, front-loading the with/without branching. Nothing extraneous and no repetition of schema content.

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?

There's no output schema, so the description is the only source for return shape, yet it only says results are ranked — no mention of which fields come back (rank, score, agent id) or any result cap. For a read tool with an optional param this is workable but leaves a gap an agent may care about.

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 `game` is already documented as a game id. The description still earns credit by explaining what the parameter actually changes about the output (score ranking vs. activity ranking, plus the eligibility threshold), 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 names the resource (agents) and the two ranking criteria: average score when a game is supplied, activity otherwise. It's clear what the tool returns, though the verb is only carried by the title and there's no explicit differentiation from siblings like get_agent or list_games.

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 explains how behavior branches on the optional `game` parameter, which is the main usage decision. But it never states when to prefer this over get_agent or other ranking-adjacent siblings, so the guidance is implied rather than explicit.

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