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

The readOnlyHint/openWorldHint annotations already cover the safety profile, and the description adds a genuinely important trait annotations cannot express: it is a paid call at $0.003 USDC via x402. It also discloses the shape of the returned book (size, prices, PnL, redeemable winnings, recent trades). It stops short of noting rate limits or pagination.

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?

Three tight sentences, front-loaded with what is returned, then why to call it, then cost last. Every sentence carries distinct information with no padding.

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 properly enumerates the returned fields, and it flags the x402 payment cost up front. Remaining gaps are minor operational details (pagination, rate limits) rather than anything that would cause a mis-call.

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?

One required parameter with 0% schema description coverage, so the description carries the burden. Saying 'Any Polymarket wallet's' does clarify that the wallet is a Polymarket-venue wallet specifically, and 'check your own book' hints it can be the caller's address, but no address format or identifier conventions are given.

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?

Names a specific resource and scope: open Polymarket positions for any wallet, with the returned fields enumerated. This is clearly distinguishable from siblings like predictions_book (order book) and perps_positions (different venue/instrument), so an agent can route correctly without opening schemas.

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?

Gives concrete usage contexts — 'Follow sharp traders or check your own book' — which tells the agent when this tool is relevant. It does not name alternatives (e.g. predictions_book, perps_positions) or state exclusions, so it stops short of explicit when-not guidance.

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