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

Despite annotations already indicating a read-only, idempotent, non-destructive operation, the description adds substantial behavioral detail: it walks the order book ladder, returns specific metrics (top_of_book, vwap_fill_price, slippage, etc.), explains the verdict values, describes how size_usd is interpreted in both modes, and warns about partial basket fills creating directional risk. 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 dense but well-structured, with clear section labels (REQUIRES, SINGLE-MARKET, BASKET, USE THIS). Every sentence contributes actionable information, from mode-specific parameters to returned fields and risk warnings. It front-loads the core purpose and then efficiently elaborates without redundancy.

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?

Given there is no output schema, the description fully compensates by enumerating the return values for both single-market and basket modes, including verdict values and risk metrics like thin_legs and forced_directional_risk. It also provides the rationale for using the tool, covering 'why' as well as 'what' and 'how,' making it complete for real-world usage.

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?

While the input schema covers 100% of parameters with descriptions, the tool description goes further by explaining the dual-mode semantics: for market it specifies that size_usd is 'max spend on buys, target proceeds on sells,' and for basket it interprets size_usd as settlement notional S (shares per leg). It also details the side parameter defaults and the auto-selection logic, adding meaning 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 clear, specific statement: 'Realizable-vs-theoretical edge check against live CLOB order-book depth.' It distinguishes itself from sibling tools by focusing on fill risk/order-book depth rather than just arbitrage detection or edge calculation, and it explicitly references when to use it (before acting on arb 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 usage guidance: 'USE THIS before acting on any polymarket_arbitrage SELL/BUY-EVERY-LEG signal or any polymarket_edges trade above ~$500.' It also clearly differentiates single-market vs basket modes and explains the auto behavior for basket side, leaving no ambiguity about when to invoke the tool.

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