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

While annotations already declare read-only and non-destructive behavior, the description adds substantial operational detail: it walks the order-book ladder, returns specific fields like slippage_pp and max_fillable_usd, explains the meaning of size_usd differently for single-market vs basket modes, and notes the 'REQUIRES one of market or event' constraint. 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 deliberately structured with labeled sections (REQUIRES, SINGLE-MARKET, BASKET, USE THIS) and every sentence carries necessary information. The opening one-liner is a compact summary, and the details are dense but not repetitive. Slightly more than minimal, but appropriate for a tool with two distinct modes and multiple return fields.

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, the description compensates by enumerating return values for both single-market and basket modes, including edge cases like thin_legs[] and forced_directional_risk. It also sets expectations with default sizes and mode-specific behavior. The description is fully self-contained for an agent to decide when and how to invoke the tool.

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. The description adds meaningful layer: it clarifies that market and event are mutually exclusive, defines side defaults (single-market default buy_yes; basket auto based on partition sum), and gives the clamp range for size_usd (10–1,000,000) plus mode-dependent interpretation. This goes beyond the schema's basic field descriptions.

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 summary: 'Realizable-vs-theoretical edge check against live CLOB order-book depth,' which clearly names the verb (check) and resource (fill risk/edge against order-book depth). It explicitly differentiates from siblings by stating when to use this tool over polymarket_arbitrage or polymarket_edges, making its unique role 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?

The description gives explicit guidance: 'USE THIS before acting on any polymarket_arbitrage SELL/BUY-EVERY-LEG signal or any polymarket_edges trade above ~$500.' It also explains the consequence of not using it (partial basket fills convert an arb into an unhedged directional position), providing clear when-to-use context and excluding alternatives.

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