arena_play

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

No annotations are provided, so the description carries the full burden. It discloses that it is a dice roll, is provably fair (HMAC), accumulates score, and requires an agent key. However, it does not explicitly state that this is a wager that will modify balance or that it is irreversible, nor does it mention rate limits or nonce consumption. The 'multiplier' implies a bet, but side effects on funds are not clearly stated.

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 concise, with the main action and key constraints in the first sentence, and fairness in the second. The 'REQUIRES AGENT KEY' is a useful prerequisite. It is front-loaded and efficient, with no wasted words, though it could be even tighter by moving the requirement into annotations.

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?

For a dice-roll tool with 3 parameters and no output schema, the description covers the action, fairness, and scoring accumulation, but it omits details like what the response contains, error handling, or that a prior join is necessary (though entry_id implies it). It also does not mention whether this involves real-money wagers, which is important for an agent. Given the gambling nature, more context would be helpful.

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% with clear descriptions for each parameter: target (range and default), direction (enum with default), and entry_id (source). The description repeats the target range and direction options without adding new semantic details, so it adds minimal value beyond the schema. Baseline 3 applies for high coverage.

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 clearly states the action: 'take one dice roll on your entry' and specifies the choices (target, direction) with the risk-reward tradeoff. It distinguishes from siblings like arena_join and arena_leaderboard by focusing on the gameplay action, so an agent can immediately identify it as the roll action.

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?

The description implies usage after joining (entry_id returned by arena_join) and requires an agent key, but it does not explicitly state when to use this versus other arena tools or exclude alternatives. It gives context ('on your entry') but lacks explicit when-not or alternative references, so usage is only implied.

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