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

Annotations (readOnlyHint, openWorldHint, idempotentHint, destructiveHint false) indicate a safe, read-only check. The description adds significant behavioral context: it walks the order book ladder, returns fill details, verdict (clean|degraded|cannot_fill), and warns about forced directional risk. No contradiction—description enhances transparency beyond 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 detailed and well-structured with clear sections (REQUIRES, SINGLE-MARKET, BASKET). However, it is somewhat verbose; some sentences could be condensed (e.g., listing all return fields in a single phrase). Still, every sentence adds value, and the structure aids readability.

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 the tool's complexity (two modes, no output schema, 4 parameters), the description is complete. It lists all returned fields for each mode, explains the risks (thin legs, forced directional risk, partial fills), and provides actionable thresholds (trades above ~$500). The absence of output schema means the description must carry this information, which it does thoroughly.

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% (all 4 parameters described in schema). The description adds meaning beyond schema: explains market vs event modes, side defaults and logic (auto-detection in basket mode), size_usd interpretation differences for single-market vs basket, and clamp range. It also clarifies how returned outputs map to parameters (e.g., max_fillable_usd relates to size_usd).

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 performs a 'realizable-vs-theoretical edge check against live CLOB order-book depth'. It distinguishes between single-market and basket modes and explicitly returns key metrics like top_of_book, vwap_fill_price, slippage, and verdict. It also differentiates from sibling tools like polymarket_arbitrage and polymarket_edges by positioning itself as a prerequisite check.

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 says '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 on thin books is not capturable, and partial basket fills convert an arb into unhedged directional position. This provides clear when-to-use and when-not-to-use guidance, plus names alternative tools.

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