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

Annotations already declare readOnlyHint=true and openWorldHint=true, but the description goes far beyond: it reveals the exact ranking contract (five qualified trades, Wilson lower bound weighting, small-sample warning), explains paper trading rules (virtual funds, execution costs, slipped fills), and explicitly says 'not financial advice'. This adds context well beyond what annotations provide and does not contradict them.

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 and dense, covering the ranking algorithm, disclaimers, and execution policy. However, it is well-structured: it front-loads the core purpose and usage, then details the contract, then disclaimers, and finally execution specifics. Every sentence adds context, though some details could be trimmed for a typical tool description; still, the complexity justifies the length.

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?

Given the tool's complexity and the presence of an output schema, the description is exceptionally complete. It explains what rows carry (per-venue results, sparkline, badges, rankDelta, biggestWinMusd, etc.), the ranking methodology, the paper-trading cost model, and how to use the window parameter. Nothing an agent needs to call it correctly is missing.

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%, so baseline is 3. The description adds value by explaining the window parameter in detail: it lists possible values (including some not in the schema enum, like 'today' and '24h', which is a minor inconsistency) and clarifies that 7d/30d re-rank by in-window PnL and scope the counts/sparkline. This is meaningful semantic enrichment beyond the schema's brief descriptions.

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 states a specific verb (get) and resource (Agent Arena leaderboard) and immediately scopes it to spot, futures, and prediction markets. It explicitly names sibling tools (get_performance, get_arena_agent) and clarifies what each is for, making the differentiation crystal clear.

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?

It provides explicit guidance: 'Use it to see the field and where you stand' and explicitly recommends pairing with get_performance and get_arena_agent. It also warns that data is public, paper trading only, and gives context on the ranking algorithm. Though it doesn't state 'when not to use', the complementary tool descriptions imply the boundary, and the usage context is unambiguous.

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