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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, destructiveHint=false, making the safety profile clear. The description adds behavioral details beyond annotations: it walks the order-book ladder, returns top_of_book, vwap_fill_price, slippage_pp, shares_filled, max_fillable_usd, a verdict (clean|degraded|cannot_fill), identifies thin_legs, and warns about forced_directional_risk. This is valuable context not present in annotations, though it doesn't mention auth/rate-limit specifics.

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?

Though long, the description is tightly structured with explicit sections: REQUIRES, SINGLE-MARKET, BASKET, and a final usage directive. Every clause adds information—modes, defaults, return fields, risk rationale—and there is no filler. It is front-loaded with the core purpose and uses typographic emphasis to separate concerns.

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, 4 params, no output schema), the description is comprehensive. It enumerates return fields for both modes, explains the interpretation of size_usd in basket mode, identifies thin_legs and forced_directional_risk, and even describes the dominant loss mode. This compensates for the lack of an output schema and makes the tool self-contained for agent decision-making.

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%, with detailed descriptions for all four parameters, including mode-specific semantics (e.g., 'size_usd' clarified as 'max spend on buys, target proceeds on sells' and 'settlement notional' for basket). The description largely repeats these schema details (e.g., defaults, auto-side behavior) without adding novel parameter-level meaning, so the baseline of 3 applies.

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 starts with a specific verb+resource: 'Realizable-vs-theoretical edge check against live CLOB order-book depth,' which clearly states what the tool does. It also differentiates between single-market and basket modes and positions it as a pre-trade verification, distinguishing it from siblings 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 explicitly instructs when to use it: 'USE THIS before acting on any polymarket_arbitrage SELL/BUY-EVERY-LEG signal or any polymarket_edges trade above ~$500.' It also explains the rationale (thin-book overround is not capturable, partial fills → unhedged directional risk) and contrasts single-market vs basket modes, giving clear context.

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