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

Annotations already declare readOnly/idempotent/non-destructive, so the description's main added value is the per-call cost ($0.002/call), which matters for an agent deciding whether to invoke. It also discloses the response item shape. Missing rate/limit behavior or note on what an empty leaderboard means.

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?

One compact sentence plus a usage clause; the item schema is front-loaded so an agent knows the return shape immediately. Dense to the point of terseness, but nothing is wasted.

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?

No output schema exists, yet the description fully enumerates the returned item fields, and defaults/scope are implied by the enums. The only substantive gap is the unmentioned `limit` bound and any default period/by behavior.

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 0%, so the description carries the burden — and it does supply the enum values for both `period` (day/week/month/all) and `by` (pnl/volume). The `limit` parameter (1-50) is never mentioned, leaving one of three params entirely 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?

States a specific resource (Polymarket top traders) with the exact return fields and the two ranking axes, and explicitly distinguishes itself from the sibling polymarket_top. An agent can tell instantly what data comes back.

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?

"Use to see which Polymarket traders made the most PnL or volume; for markets use polymarket_top" gives a clear positive trigger and names the nearest alternative. Other Polymarket siblings (polymarket_edge, polymarket_context) aren't differentiated, so it stops short of full when/when-not coverage.

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