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

The description adds significant behavioral context beyond the annotations, which already indicate read-only, open-world, idempotent, and non-destructive behavior. It explains how the tool walks the order-book ladder, returns verdicts like 'clean|degraded|cannot_fill', and highlights the risk of partial basket fills converting arbs into directional positions.

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 relatively long but well-structured, with clear mode separation and front-loaded with the main purpose. Every sentence provides necessary guidance, so the length is justified. Slightly verbose but not wasteful.

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?

Despite lacking an output schema, the description thoroughly enumerates the return values for both modes (top_of_book, vwap_fill_price, slippage_pp, etc.) and explains per-leg fill details and thin_legs. It also covers the dominant loss mode, making it complete for a complex tool.

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?

With 100% schema description coverage, the baseline is 3, but the description adds valuable semantic nuance. For example, it explains that size_usd is interpreted as 'settlement notional S (shares per leg)' in basket mode, and clarifies side defaults based on partition sum. This goes beyond the schema's basic 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 clearly states the tool's function as a realizable-vs-theoretical edge check against live order-book depth. It distinguishes between single-market and basket modes and explicitly differentiates from sibling tools like polymarket_arbitrage and polymarket_edges by specifying when to use them.

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 states when to use this tool: before acting on any polymarket_arbitrage SELL/BUY-EVERY-LEG signal or any polymarket_edges trade above ~$500. It also provides warnings about theoretical overround on thin books and partial basket fills, giving clear usage context.

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