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

The description discloses the tool's internal behavior in detail: it 'walks the ladder' to compute fill prices, returns a verdict, and in basket mode identifies thin legs and forced directional risk. It doesn't contradict the annotations (readOnlyHint, idempotentHint, etc.) and adds context about the live order-book depth and the specific outputs.

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 lengthy but well-structured, starting with the core purpose and then breaking down the two modes with clear formatting (SINGLE-MARKET, BASKET). Every sentence carries functional information; while it could be tightened, the complexity of the tool justifies the length.

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?

Given the absence of an output schema, the description thoroughly enumerates the return fields for both modes, including top_of_book, vwap_fill_price, slippage_pp, shares_filled, verdict, and basket-specific outputs like capture_ratio, thin_legs, and forced_directional_risk. It also covers prerequisites and the strategic context, making it a complete guide for an agent.

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 four parameters, the description adds significant semantic context: it explains that size_usd is 'max spend on buys, target proceeds on sells' in single-market mode and 'settlement notional S (shares per leg)' in basket mode. It also explains default side behavior in basket mode, going well beyond the schema.

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 states the tool's purpose as a 'Realizable-vs-theoretical edge check against live CLOB order-book depth,' which is a specific verb+resource. It clearly distinguishes between single-market and basket modes, making it distinct from sibling tools like polymarket_arbitrage and polymarket_edges.

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,' providing clear when-to-use guidance. It also explains the failure mode (partial basket fills convert an arb into an unhedged directional position), which helps an agent decide between this and alternatives.

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