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

Annotations already establish readOnly/idempotent semantics, yet the description adds substantial non-obvious behavior: the day/week/month profit figures include open positions at current prices whereas all-time is realized only, and per-category volume is null because Polymarket doesn't publish it. Those are exactly the caveats an agent would otherwise misinterpret when reporting numbers.

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?

Front-loaded with the triggering use cases before the return details and caveats, so an agent can decide early. It runs long, and the two closing prohibition sentences overlap with each other and partly restate readOnlyHint, which is the only wasted space.

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?

For a 4-parameter, all-optional, enum-driven read tool with an output schema, everything needed to call and interpret it is present: defaults, return fields, period definitions, and the category/volume caveat. Nothing material 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 the baseline is 3, but the description adds real meaning well beyond the schema: it explains the accounting difference between period values (open positions at current prices vs realized-only all-time) and the null-volume consequence of category boards. Limit and metric are only restated from the schema, so it stops short of a 5.

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 verb and resource: ranks Polymarket traders by profit or volume. It distinguishes itself from siblings like get_trader_profile and get_trader_positions by scoping to the aggregate leaderboard, and the concrete example queries remove any ambiguity about the resource.

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?

Explicit when-to-use triggers are given with example phrasings ("top Polymarket traders this month", "highest-volume traders this week"), and there are explicit when-not clauses: don't use it to pick a market/trader to invest in, and don't call it for buy recommendations. The alternative for choosing markets is implied by the sibling set rather than named, but the exclusions are unusually clear.

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