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

Annotations already declare readOnlyHint=true and destructiveHint=false, but the description adds deep behavioral context: it walks the ladder, returns specific fields (top_of_book, vwap_fill_price, slippage_pp, verdict), interprets size_usd differently by mode, and warns about partial-fill risk converting an arb into an unhedged position. No contradictions 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 long but well-structured: it opens with the core purpose, then breaks into SINGLE-MARKET and BASKET sections with clear parameter mappings and output lists. Every sentence adds useful information, though it could benefit from bullet points. It's appropriately detailed for a complex tool.

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 no output schema and 4 params with no required ones, the description fully compensates: it enumerates return fields for both modes, explains the verdict values, identifies risky legs, and provides context on when theoretical edge is not capturable. It's complete enough for an agent to understand tool behavior and output before invocation.

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%, so baseline is 3. The description goes beyond schema by explaining how size_usd maps to 'max spend on buys, target proceeds on sells' and basket 'settlement notional S (shares per leg; each share pays $1)', plus clarifies automatic side detection in basket mode. These are semantic clarifications the schema alone doesn't fully convey.

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 leads with a specific verb+resource: 'Realizable-vs-theoretical edge check against live CLOB order-book depth.' It clearly distinguishes itself from sibling tools like polymarket_arbitrage and polymarket_edges by explaining it's a pre-trade risk check for 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?

Explicit when-to-use guidance: 'USE THIS before acting on any polymarket_arbitrage SELL/BUY-EVERY-LEG signal or any polymarket_edges trade above ~$500.' It also explains why (theoretical overround on thin books is not capturable) and describes two modes (single-market vs basket), which helps the agent choose between them.

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