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

Annotations already indicate readOnlyHint, openWorldHint, idempotentHint, and non-destructive. The description adds significant behavioral context: it walks the order-book ladder, returns verdicts (clean/degraded/cannot_fill), explains how partial basket fills convert arb into directional risk (the dominant loss mode), and names 'thin_legs' and 'forced_directional_risk'. This goes well beyond the annotation signals.

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 verbose (200+ words) but well-structured with clear section headers (REQUIRES, SINGLE-MARKET, BASKET, USE THIS). Every sentence adds value, but some could be tightened. The front-loading of the core purpose and mode requirements is excellent, making it easy to scan.

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 no output schema, the description fully explains the return values for both modes (e.g., top_of_book, vwap_fill_price, slippage_pp, shares_filled, verdict; for basket: theoretical_sum vs realizable_sum, capture_ratio, profit_usd, per-leg fill detail, thin_legs, max_clean_notional_usd, forced_directional_risk). It covers edge cases like partial fills and directional risk, making it complete for this 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?

Schema description coverage is 100%, and the description adds rich semantic meaning: it explains how parameters like side and size_usd behave differently in single-market vs. basket modes, provides defaults and constraints, and clarifies the interpretation of size_usd (max spend vs. target proceeds vs. settlement notional). This goes far 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 purpose: 'Realizable-vs-theoretical edge check against live CLOB order-book depth.' It distinguishes between single-market and basket modes with specific verbs and outcomes, and it stands apart from sibling tools like polymarket_arbitrage and polymarket_edges by specifying when to use this tool (before acting on those signals).

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 guidance: 'USE THIS before acting on any polymarket_arbitrage SELL/BUY-EVERY-LEG signal or any polymarket_edges trade above ~$500.' It explains why (theoretical overround not capturable, partial fills create directional risk) and delineates when not to use it by omission (e.g., for small trades). This is exemplary usage guidance.

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