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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is clear. The description adds substantial behavioral detail: it walks the order-book ladder, returns top_of_book/vwap_fill_price/slippage_pp, identifies thin_legs, and explicitly discloses the dominant loss mode (partial basket fills converting into unhedged directional positions). 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 operational value: it front-loads the core purpose, then clearly organizes content into SINGLE-MARKET and BASKET sections with explicit parameter interpretations, return fields, and risk notes. Every clause earns its place, and the structure aids navigation despite 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?

With no output schema, the description bears the burden of explaining return values, and it does so comprehensively: it lists all key outputs for both modes (top_of_book, vwap_fill_price, slippage_pp, shares_filled, max_fillable_usd, verdict, capture_ratio, profit_usd, thin_legs, forced_directional_risk, etc.). It also covers mode selection, defaults, clamping, and real-world failure modes, making it highly 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?

Schema coverage is 100% and each parameter has a descriptive schema entry, but the description adds critical mode-dependent semantics: size_usd means 'max spend on buys, target proceeds on sells' in single-market mode and 'settlement notional S (shares per leg; each share pays $1)' in basket mode. It also explains side defaults, including the auto behavior in basket mode, which goes 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 opens with a specific verb phrase: 'Realizable-vs-theoretical edge check against live CLOB order-book depth,' which precisely defines the tool's function. It further distinguishes itself from siblings by explicitly naming polymarket_arbitrage and polymarket_edges and positioning this tool as the fill-risk validator, not the signal generator.

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 gives an explicit usage directive: 'USE THIS before acting on any polymarket_arbitrage SELL/BUY-EVERY-LEG signal or any polymarket_edges trade above ~$500.' It also explains why, warning that theoretical overround on thin books is not capturable and that partial basket fills create unhedged directional risk, which is excellent contextual guidance.

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