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

Annotations already declare the tool as read-only, idempotent, and non-destructive. The description adds significant behavioral context: it details the return values (top_of_book, vwap_fill_price, slippage_pp, etc. for single-market; theoretical_sum vs realizable_sum, capture_ratio, profit_usd, thin_legs, etc. for basket) and warns about the risk of partial basket fills converting an arb into an unhedged directional position. This goes well beyond the 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 (over 250 words) but well-structured with clear sections for SINGLE-MARKET and BASKET modes. The first sentence clearly states the purpose and the requirement for one of two parameters. Every sentence adds necessary detail; there is no obvious redundancy. The length is justified by the complexity of describing two modes and associated risks.

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 high schema coverage, rich annotations, and no output schema, the description provides a complete picture. It explains the tool's purpose, prerequisites (one of market or event), mode-specific behaviors, return values, and even the risk of directional exposure. This is sufficient for an agent to select and invoke the tool correctly.

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 has 100% description coverage, providing a baseline of 3. The description adds significant meaning by explaining the interaction between 'side' and mode (single-market vs basket) and clarifying the interpretation of 'size_usd' for each mode (spend vs target proceeds for single-market; settlement notional for basket). This additional semantics helps the agent use parameters correctly.

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' and specifies two distinct modes (single-market and basket). It distinguishes itself from sibling tools like polymarket_arbitrage and polymarket_edges by explicitly recommending its use before acting on their 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 explicitly states when to use this tool: 'USE THIS before acting on any polymarket_arbitrage SELL/BUY-EVERY-LEG signal or any polymarket_edges trade above ~$500'. It explains the rationale (theoretical overround on thin books is not capturable, partial fills create directional risk). However, it does not discuss alternative tools or scenarios where it should not be used, leaving some gaps.

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