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

Beyond the readOnly/openWorld annotations, it discloses the data-scope limitation (Polymarket's Data API only lists top holders, so percentages cover those wallets, not full outcome supply), the 50-per-outcome cap, and the pricing model ($0.003 USDC via x402 on Base/Solana/Arc, no charge for failed calls). The failure-billing and scope caveats are exactly the kind of context annotations cannot carry.

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 core purpose, scope caveat, cap and price are front-loaded in a single efficient paragraph. The 'Information only, not financial advice' sentence is boilerplate disclaiming that doesn't help an agent decide or invoke, costing it the top score.

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 an output schema present, return-value documentation is optional, yet the description still summarises what each holder record contains. Combined with the scope caveat, cap, prerequisite endpoint and pricing, an agent has everything needed to call it correctly.

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 description coverage is 100% — limit is documented as 'Holders per outcome, 1 to 50, default 20' and market as the condition id from /api/pm/event. The description's 'Up to 50 per outcome' merely echoes the schema, adding no syntax or format detail beyond it, so the baseline of 3 applies.

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 opening sentence names a specific verb and resource — the top position holders of every outcome of one Polymarket market — and enumerates the returned fields (wallet, public name, shares, share-of-total). This is clearly distinct from siblings like pm_trades, pm_orderbook, pm_activity and pm_leaderboard.

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 gives a clear input dependency by telling the agent the market id comes from /api/pm/event, which implies usage context. However, it never states when to prefer this over pm_leaderboard, pm_wallet or pm_trades, and offers no explicit exclusions, so guidance remains implied rather than directive.

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