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

The annotations already declare readOnlyHint=true and openWorldHint=false, so the safe-read profile is covered. The description adds useful context by naming two distinct leaderboard modes and noting the daily one is UTC-based, but says nothing about error cases, empty boards, or result ordering.

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 with the resource front-loaded and zero filler. Nothing is repeated from the title beyond what adds meaning.

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 and 0% parameter documentation, more was needed: whether day is required for the daily mode, what the board returns, and how many entries. The description covers the core intent but leaves those operational questions open.

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%, so the description must carry the load. It partially does: 'free-play or UTC daily' maps onto the mode enum (free/daily) and 'one game' matches the game enum, but the day parameter is never explained (its format is only conveyed by the schema pattern), nor is the default mode=daily called out.

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 gives a specific verb ('Read') and resource ('leaderboard'), and narrows scope to 'one game' plus the two leaderboard flavors. It distinguishes itself from siblings like arcade_read_replay or arcade_public_profile implicitly, but never names a sibling to route the agent explicitly.

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?

Usage is only implied: an agent can infer you call this when you want a leaderboard, but there is no statement of when to prefer it over arcade_challenges, arcade_public_profile, or arcade_read_replay. No prerequisites or exclusions are given.

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