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

Annotations already indicate readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds valuable behavioral context: it 'walks the ladder' and returns specific fields like top_of_book, vwap_fill_price, slippage, etc. It also details basket mode returns and the risk of thin legs. 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 well-structured with clear sections for SINGLE-MARKET and BASKET modes, using bold for key terms. It is front-loaded with the main purpose. While somewhat lengthy, every sentence adds value given the tool's complexity. Minor redundancy is acceptable.

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, multiple return values) and the absence of an output schema, the description is remarkably complete. It explains all return fields for both modes, highlights risks (thin_legs, forced_directional_risk), and provides usage context. No significant gaps.

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%, but the description adds meaning beyond the schema. It explains the mutual exclusivity of 'market' and 'event' parameters, and clarifies 'size_usd' in basket mode as 'settlement notional — shares per leg, each paying $1 at resolution.' It also provides defaults and constraints, enriching 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 starts with 'Realizable-vs-theoretical edge check against live CLOB order-book depth,' clearly defining the tool's function. It distinguishes between single-market and basket modes, and the title 'polymarket_fill_risk' is descriptive. The purpose is specific and differentiated from sibling tools like polymarket_arbitrage and polymarket_edges.

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: 'USE THIS before acting on any polymarket_arbitrage SELL/BUY-EVERY-LEG signal or any polymarket_edges trade above ~$500.' It provides when-to-use and when-not-to-use guidance, explaining risks like theoretical overround on thin books and partial basket fills converting arbs into directional positions.

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