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

Annotations already declare readOnly/openWorld/idempotent, but the description goes far beyond: it explains the tool 'walks the ladder', lists exact return fields (top_of_book, vwap_fill_price, slippage_pp, etc.), and warns that 'partial basket fills convert an arb into an unhedged directional position.' This provides nuanced behavioral context beyond the safety hints.

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 dense but well-organized, moving from core purpose to mode-specific details to usage guidance. Every sentence adds new information, though the length is considerable. The front-loaded definition makes the main function immediately clear, so it earns a high score despite its size.

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 must explain return values, and it does: both modes list all returned metrics (verdict, capture_ratio, thin_legs, etc.). It also covers conditional requirements (market OR event), parameter defaults, and risk warnings. For a tool of this complexity, the description is exceptionally 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?

Schema coverage is 100%, so baseline is 3, but the description adds substantial value: clarifies that `market` and `event` are mutually exclusive modes, explains `side` defaults and logic (auto for basket), and defines `size_usd` as 'settlement notional S (shares per leg)' with clamp range. This enriches the schema without redundancy.

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 precise verb+resource statement: 'Realizable-vs-theoretical edge check against live CLOB order-book depth.' It clearly distinguishes this tool from siblings by naming its role in the workflow (check before arbitrage or edge trades) and details both single-market and basket modes, making the purpose unmistakable.

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?

Explicitly states when to use: '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 not capturable, partial fills create unhedged directional risk), and contrasts with alternatives. This is textbook usage guidance.

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