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

Annotations declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and the description adds rich behavioral detail: it walks the order book ladder, returns top_of_book, vwap_fill_price, slippage_pp, shares_filled, max_fillable_usd, verdicts (clean|degraded|cannot_fill), and in basket mode returns theoretical_sum vs realizable_sum, capture_ratio, profit_usd, thin_legs[], max_clean_notional_usd, forced_directional_risk. It warns about partial fill risks. 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 relatively long but well-structured with sections for single-market and basket modes, using bullet-like formatting. Information is front-loaded with the core purpose. While every sentence adds value, it could be slightly more concise by moving some details to an examples section.

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 (dual mode, 4 params, no output schema, high-risk application), the description provides thorough coverage: it explains both modes fully, lists return fields, warns about thin legs and directional risk, and ties to sibling tools. It addresses the 'dominant loss mode in real arb-bot P&L'. No gaps remain.

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% (all 4 parameters have descriptions). The tool description adds significant meaning: for size_usd it clarifies interpretation as 'max spend on buys, target proceeds on sells' in single-market and 'settlement notional (shares per leg)' in basket. It explains side defaults (auto for basket based on partition sum). This goes well beyond schema descriptions.

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 does a 'Realizable-vs-theoretical edge check against live CLOB order-book depth'. It distinguishes between single-market and basket modes, and explicitly differentiates from sibling tools like polymarket_arbitrage and polymarket_edges by stating when to use this tool before acting on those 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 instructs to '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 not capturable, partial basket fills convert arb to directional risk). It provides mode selection guidance (single-market vs basket) but does not explicitly state when NOT to use the tool, leaving a minor gap.

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