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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, destructiveHint=false, establishing the tool's safe and non-destructive nature. The description adds rich behavioral details beyond annotations: it walks the ladder, returns specific fields like top_of_book, vwap_fill_price, slippage_pp, and explains risks like partial basket fills leading to unhedged positions. 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 well-structured with clear sections: REQUIRES, SINGLE-MARKET, BASKET, and USE THIS. Every sentence adds value, such as specifying default sizes, return fields, and risk warnings. It is front-loaded with the core purpose and remains concise despite the complexity.

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 fields, no output schema), the description is remarkably complete. It covers all return fields (top_of_book, vwap_fill_price, etc.), explains the risk of thin books and partial fills, and provides concrete examples of use. With no output schema, the description takes on the full burden of explaining outputs, 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 description coverage is 100% (all 4 parameters have descriptions). The description adds significant meaning beyond the schema: it explains the two modes (market vs event), default behavior for side ('auto from partition sum'), and size_usd interpretation ('max spend on buys, target proceeds on sells' for single-market, 'settlement notional S (shares per leg)' for basket). This greatly aids correct parameter invocation.

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's purpose as a 'realizable-vs-theoretical edge check against live CLOB order-book depth.' It differentiates between single-market and basket/partition modes, and explains what each mode returns, making it distinct 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 provides explicit usage 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 not capturable, partial basket fills convert arb into unhedged directional position), offering clear when-to-use and when-not-to-use context.

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