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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, and the description adds substantial behavioral context. It explains that the tool walks the order-book ladder, computes top_of_book vs VWAP, returns a verdict (clean|degraded|cannot_fill), and details basket-mode outputs. It also discloses the risk of partial fills converting an arb into a directional position. No contradiction with 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 densely packed with necessary information for a two-mode tool. It uses CAPS for mode labels, front-loads the core purpose, and every sentence contributes unique details about parameters, outputs, or usage timing. While not minimal, it is appropriately structured and free of fluff.

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 carries full responsibility for explaining return values, and it does so comprehensively. It enumerates single-market fields (top_of_book, vwap_fill_price, slippage_pp, shares_filled, etc.) and basket-mode outputs (theoretical_sum, realizable_sum, capture_ratio, profit_usd, thin_legs, forced_directional_risk). It also covers prerequisites, parameter interpretation, and risk caveats, making it complete for an agent to invoke 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?

Although schema description coverage is 100%, the description enriches parameter understanding significantly. For example, it clarifies that size_usd means 'max spend on buys, target proceeds on sells' in single-market mode and 'settlement notional' in basket mode. It also explains the market/event requirement and the default auto behavior for side in basket mode, going beyond the schema's concise 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 a specific, action-oriented summary: 'Realizable-vs-theoretical edge check against live CLOB order-book depth.' It then distinguishes two modes (single-market and basket), lists concrete output fields, and clearly differentiates the tool from siblings like polymarket_arbitrage and polymarket_edges by focusing on fill risk.

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 instructs when to use the tool: 'USE THIS before acting on any polymarket_arbitrage SELL/BUY-EVERY-LEG signal or any polymarket_edges trade above ~$500.' It provides a rationale citing theoretical overround not being capturable on thin books and partial basket fills creating unhedged directional risk, directly addressing when to use it vs alternatives.

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