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

Annotations already establish readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is fully covered and the description does not contradict it. The added context 'no stakes, no money, just a rating' is useful scoping information, but nothing is said about what the listing contains, ordering, or size limits.

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?

The description is one packed sentence with a parenthetical plus a trailing parameter note; the core purpose is not front-loaded before the embellishment. It is short but the clause about 'how to enter the weekly sealed puzzle rounds' is arguably out of scope and adds noise.

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 a single optional boolean, no output schema, and read-only annotations, the definition is minimally viable, but it never indicates what a call returns (game list, ladder standings, replay links), which is the key unknown for a no-output-schema read tool. The claim about puzzle-round entry is also unexplained relative to the round-related siblings.

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% and the single parameter is undocumented in the schema, so the description must compensate. 'Pass full:true for every game' does explain the flag's effect, implying the default is a subset, but it leaves the default value, response size, and what 'every game' spans ambiguous.

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 (a Strategy Games league with tic-tac-toe/Connect Four Elo ladder plus puzzle-round entry info) but never states an action verb such as list, browse, or fetch, so it reads as content marketing rather than a capability. It partially differentiates from siblings like arena_game_reviews and arena_leaderboard by scope, but an agent cannot tell precisely what the call returns.

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 alternative named among the many arena_* siblings (e.g., arena_try_round, arena_round_tasks, arena_leaderboard) even though the description mentions puzzle-round entry, which sounds like a different tool's job. The only actionable instruction is the parameter note about full:true.

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