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

Beyond the read-only/annotations, the description discloses detailed behavioral traits: it 'walks the ladder', computes VWAP fill prices, returns a clean/degraded/cannot_fill verdict, and identifies forced_directional_risk. It warns about partial basket fills and thin books, which are non-obvious but critical behaviors. No contradiction with the readOnlyHint, idempotentHint, or destructiveHint annotations.

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 description is long, but it is front-loaded with the core purpose and uses uppercase mode markers (SINGLE-MARKET:, BASKET:) to structure the content. Every sentence adds operational detail with no filler. It borders on essay-length, but the dual-mode complexity justifies the density, so it earns a 4 rather than a 5.

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 fully enumerates return values for both modes (top_of_book, vwap_fill_price, slippage_pp, capture_ratio, thin_legs[], etc.) and even explains error conditions like cannot_fill. It covers defaults, parameter constraints, and the risk rationale. The only minor omission is explicit rate-limit or error-handling notes, but overall it is complete for safe invocation.

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?

Although the input schema already covers all 4 parameters, the description adds essential semantic depth: `size_usd` means max spend on buys but target proceeds on sells, and in basket mode it becomes settlement notional per share. It also explains `side` defaults (buy_yes vs auto) and the market/event mode selection, going well beyond the schema's one-line descriptions.

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 description opens with 'Realizable-vs-theoretical edge check against live CLOB order-book depth', a specific verb+resource phrase that precisely defines the tool's function. It clearly distinguishes itself from sibling tools like polymarket_arbitrage and polymarket_edges by focusing on fill risk rather than edge discovery, and the two-mode breakdown (single-market vs basket) adds clarity.

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?

The description explicitly says 'USE THIS before acting on any polymarket_arbitrage SELL/BUY-EVERY-LEG signal or any polymarket_edges trade above ~$500', naming exact sibling tools and a threshold. It also explains the consequence of not using it (theoretical overround not capturable, partial fills convert arb into unhedged directional position), giving clear when-to-use context.

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