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

Annotations already declare readOnly/idempotent/non-destructive, but the description goes far beyond by detailing exact return fields (top_of_book, vwap_fill_price, slippage_pp, etc.) and explaining behavioral nuances like 'forced_directional_risk naming the legs most likely to strand you unhedged.' 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 long but dense—every sentence adds distinct value. It front-loads the core purpose, then methodically covers constraints, both modes, return values, and usage context. No fluff or repetition; the length is justified by the tool's 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?

With no output schema, the description fully inventories return values for both modes (e.g., theoretical_sum, capture_ratio, thin_legs, max_clean_notional_usd). It explains the risk model and the meaning of key terms like 'settlement notional.' For a max-complexity tool (two modes, 4 params), this is complete.

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?

While schema coverage is 100%, the description adds meaning beyond schema: it explains that `size_usd` is 'max spend on buys, target proceeds on sells' in single-market mode and 'settlement notional S' in basket mode, plus clarifies `side` defaults for each mode. This interpretive layer is not present in 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 opens with a specific verb+resource: 'Realizable-vs-theoretical edge check against live CLOB order-book depth.' It clearly distinguishes single-market and basket modes, and explicitly references sibling tools (polymarket_arbitrage, polymarket_edges) to differentiate when this tool is used.

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?

Provides 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.' Even explains the risk of partial fills converting an arb into unhedged directional positions, which justifies the tool's necessity.

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