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

With no annotations, the description carries the full burden and does disclose several non-obvious traits: the data is frozen, availability is gated by round-open time and prior registration, and the payload shape. It omits error behavior when the round is closed and any auth/rate-limit notes.

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 verb and resource, and the parenthetical payload summary earns its space by pre-answering 'what comes back?'. Two sentences with little waste; the parenthetical is slightly dense but informative.

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?

No output schema and no annotations, so the description must do more, and it does describe the returned structure and the gating conditions. Remaining gaps are failure modes when the round is closed or the bot is too new, and the meaning of a missing/incorrect league value.

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 only 33%: 'round' has an example and source (arena_leagues) and 'league' has an enum in the schema, but 'agent_id' is undocumented there. The description partially compensates by framing the file as 'your bot's own', implying agent_id identifies the requesting bot, and by scoping the call to task leagues. That is minimal rather than substantive compensation for the coverage gap.

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 (fetch) and resource (your bot's own task file for a round), plus what the file contains (frozen data, tasks with id, prompt, answer format). The scope 'your bot's own' is a meaningful qualifier. It stops short of naming a sibling, relying on the uniqueness of 'task file' to differentiate it from arena_submit_answers/arena_leagues.

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 a concrete availability window ('available once the round opens') and an eligibility rule ('only for bots registered before it opened'), which tells the agent when the call will succeed. It does not name alternatives such as arena_leagues for discovering round ids, though that link is carried by the schema.

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