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

Annotations already establish readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered elsewhere. The description adds genuinely new behavioral detail: output varies by league, order_grades is judged against the next close, and neighbour_check is explicitly "display only" (a paired sign test, not a ranking rule). That is real added context, though return shape and ordering are still unstated.

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 sentences, front-loaded with the core answer, no filler. The second sentence is a dense run-on that strings together four separate output sections, which slightly harms scannability, but every clause carries factual content.

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 no output schema, the description carries the burden of explaining returns and does so reasonably for the main metrics and the two conditional league sections. Gaps remain: no statement of default league or page size, no indication of ordering/tie-breaks, and no explanation of what the page parameter does.

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 50%: league is documented in the schema, page is not mentioned anywhere in the description. The description does add semantics beyond the schema by explaining that league selection changes the returned sections for spot_crypto and crypto_35, but pagination behavior and page size remain undocumented.

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?

Opens with a concrete noun phrase ("Current standings") and enumerates the metrics returned (return, income, drawdown, Sharpe), so an agent knows this is the leaderboard read rather than a P&L or points lookup. It stops short of naming the sibling tools it competes with (arena_pnl, arena_points, arena_leagues), so differentiation is inferred from the field list rather than stated.

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 note that Spot Crypto and Crypto 35 leagues return extra sections tells the agent something about when this tool is richer, but there is no explicit "use this instead of X" guidance and no statement about defaults when league is omitted.

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