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

No annotations are provided, so the description carries the burden. It usefully discloses that the call is free, what the result contains (pot size, entrant count), and the timezone semantics, but says nothing about authentication, rate limits, or pagination behavior.

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?

Two short clauses, front-loaded with the cost tag and the resource name, with the optional parameter note appended where it belongs. No filler text, though the inline '[FREE]' prefix is slightly awkward.

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 an output schema present, return values need not be explained, and the one parameter's format and timezone are covered. The description is complete enough for an agent to invoke the tool correctly; only auth/rate-limit context is absent.

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 single 'day' parameter has 0% schema description coverage, yet the description compensates by specifying the accepted format (YYYY-MM-DD) and the timezone (America/Phoenix), which the schema does not convey. This is meaningful added value over the bare schema.

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 resource (Coin Duel leaderboard) and names what it returns (pot size and entrant count), which distinguishes it from generic siblings like get_leaderboard, data_leaderboard, and venture_leaderboard. The verb is implicit ('returns'/'shows') rather than stated, keeping it just below a top score.

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?

Usage is implied: the [FREE] tag signals no cost, and the 'Today's ... leaderboard' framing tells the agent to call it to view current standings. However it never states when to prefer coinduel_rules or coinduel_enter_info, nor any exclusions, so no explicit routing guidance exists.

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