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

No annotations are provided, so the description carries the full disclosure burden, and it does so substantively: entry cost, round duration, call-close timing, price oracle source, ranking methodology, pot cap, and payout cadence. It does not explicitly state that the tool is a side-effect-free read, though '[FREE]' and the info-tool nature imply 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?

It is a single dense sentence with the '[FREE]' tag front-loaded and a colon-delimited list where each clause is a distinct, useful constant. The run-on structure is slightly heavy but nothing is wasted.

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?

An output schema exists, so return-value explanation is not required, and the description supplies the key domain constants an agent needs. It is essentially complete for a zero-parameter info tool, with only the absence of sibling routing as a minor gap.

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?

The tool takes zero parameters, so per the rubric the baseline is 4. There are no parameter semantics to clarify, and the schema coverage is trivially complete.

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 identifies this as the rules/constants reference for Coin Duel, using a specific resource ('Coin Duel rules and constants') and enumerating the exact constants returned. It does not explicitly distinguish itself from the related siblings coinduel_enter_info and coinduel_leaderboard, which is why it falls short of a 5.

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, no mention of alternatives, and no prerequisites or exclusions. An agent must infer that this is the reference to consult before entering, but the description itself provides no routing information relative to coinduel_enter_info.

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