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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds valuable behavioral context: it walks the ladder, returns specific fields like top_of_book, vwap_fill_price, slippage_pp, and warns about partial basket fills leading to 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 lengthy but well-organized with clear headers (SINGLE-MARKET, BASKET) and bullet-point-like details. Every sentence adds value, though a slight reduction is due to the overall length—some trimming could improve readability without losing information.

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?

Despite lacking an output schema, the description comprehensively lists all return fields for both modes, including edge cases like thin_legs[] and forced_directional_risk. It covers crucial warnings about partial fills and directional risk, making it complete for the tool's complexity.

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%, so baseline is 3. The description adds significant meaning beyond the schema: it explains how size_usd is interpreted differently in single-market vs. basket modes, provides defaults for side and size_usd, and clarifies that event is for basket mode and market for single-market. This extensive context raises the score.

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 it performs a 'realizable-vs-theoretical edge check against live CLOB order-book depth.' It distinguishes between single-market and basket modes, and the specific verb 'check' and resource 'order-book depth' make the purpose unambiguous. This effectively differentiates it from siblings 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 tells when to use the 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 basket fills convert arb to unhedged directional position). However, it doesn't explicitly state when not to use it or list alternatives, so it loses one point.

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