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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds substantial behavioral context: it details what happens in single-market vs basket mode, lists return fields like top_of_book and vwap_fill_price, warns that partial basket fills convert an arb into an unhedged directional position, and explains the verdict categories. This far exceeds the annotation baseline, with no contradictions.

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?

Though long, the description is highly efficient and well-structured: it opens with the core purpose, then clearly separates SINGLE-MARKET and BASKET behavior, lists return fields compactly, and ends with concrete usage guidance. Every sentence earns its place, and the density is justified given the tool's complexity.

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 compensates by enumerating many return values (top_of_book, vwap_fill_price, slippage_pp, shares_filled, max_fillable_usd, verdict, theoretical_sum, realizable_sum, capture_ratio, profit_usd, per-leg fill detail, thin_legs[], max_clean_notional_usd, forced_directional_risk). It covers dependencies (requires market or event), defaults, and the risk rationale, making it a complete guide for 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?

Schema coverage is 100%, but the description adds crucial depth: it clarifies that size_usd means 'max spend' for buys, 'target proceeds' for sells in single-market mode, and 'settlement notional' (shares per leg) in basket mode. It also explains the side parameter's valid values per mode and the auto-detection logic for basket mode. This is a strong enrichment 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 clearly states the tool's purpose as a 'Realizable-vs-theoretical edge check against live CLOB order-book depth.' It explicitly distinguishes between single-market and basket modes, and names the sibling tools it complements (polymarket_arbitrage, polymarket_edges), making its unique role obvious.

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 provides explicit usage context: 'USE THIS before acting on any polymarket_arbitrage SELL/BUY-EVERY-LEG signal or any polymarket_edges trade above ~$500.' It mentions the alternatives (arbitrage and edges tools) and implies when not to use (below the threshold), giving clear guidance for selection.

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