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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds non-obvious behavior the annotations cannot convey: the data is frozen, availability is gated on round opening, and only pre-registered bots may call it.

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 front-loaded sentence; the parenthetical payload enumeration earns its space. Slightly dense but no filler or redundancy.

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 sketches the return payload (frozen data plus tasks with id, prompt, exact answer format). For a 3-parameter read tool with annotations covering safety, this is nearly complete; only parameter-level detail is thin.

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 only 33% (only 'round' is documented; league's enum and agent_id are bare). The description loosely implies agent_id is the caller's own bot and that a round is required, but adds no format, source, or constraint detail to compensate for the two undocumented parameters.

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 verb and resource ('fetch your bot's own task file for a round') and even enumerates the returned content (frozen data, tasks with id, prompt, answer format). The 'your bot's own' scoping distinguishes it from sibling submission/listing tools like arena_submit_answers, though no sibling is named outright.

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?

Gives real eligibility conditions ('available once the round opens, only for bots registered before it opened'), which tells the agent when the call will succeed or fail. It does not, however, contrast this tool with alternatives such as arena_try_round or arena_submit_answers, so the routing 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.