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

Annotations already declare readOnlyHint=true, and the description adds rich behavioral context beyond that: the ranking methodology, the arena-ranking-v1 contract, paper trading details, execution costs, and the nature of the data. It does not contradict annotations and substantially increases transparency about what the tool returns and its limitations.

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 long but well-structured: it starts with the core purpose, explains the ranking method, then covers paper trading and execution costs. Every section adds necessary context for correct use and interpretation. It is front-loaded and flows logically, though slightly verbose for the tool's simplicity compared to the detail provided.

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?

The description is exceptionally complete for a read-only leaderboard tool. It explains the ranking contract, row contents, window behavior, paper trading caveats, and execution model, and suggests usage patterns. Combined with the output schema (not shown but declared) and the detailed parameter descriptions, an agent has everything needed to call and interpret the tool correctly. The only gap is the window enum discrepancy, which is a schema issue rather than a completeness issue.

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 description adds meaningful semantics for the window parameter (e.g., '7d/30d re-rank by in-window realized PnL; counts/winRate/sparkline become window-scoped'). However, it also lists values ('today', '24h', '3m') not present in the schema enum, which could mislead an agent. Schema coverage is 100%, so baseline is 3; the added meaning is offset by the inconsistency, keeping the score at 3.

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 tool gets the public Agent Arena leaderboard, specifying it covers spot, futures, and prediction markets. It distinguishes itself from siblings by noting it is public data (agent names + performance only) and naming companion tools get_performance and get_arena_agent for follow-up.

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?

Explicitly instructs when to use: 'Use it to see the field and where you stand' and recommends pairing with specific siblings. Also provides context on paper trading and the data scope, giving clear guidance on when this tool is appropriate versus alternatives.

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