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

The annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the tool is known to be safe. The description adds substantial behavioral context: it 'walks the ladder,' returns specific metrics like slippage and max_fillable_usd, and warns about the dominant loss mode (partial basket fills converting an arb into an unhedged directional position). This far exceeds the baseline set by 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 densely packed with essential information, structured into clear sections (overview, required mode, single-market, basket, usage guidance). Every sentence adds value — no filler or tautology. The most important usage guidance is front-loaded in uppercase, and the format is easy to scan.

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, many return fields, no output schema), the description is remarkably complete. It explains the exact return values for both modes, names the risk factors (thin_legs, forced_directional_risk), and provides actionable guidance on when to use it. There is no missing information that would prevent an agent from selecting and invoking the tool correctly.

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%, so baseline is 3. However, the description adds critical semantics beyond the schema: for market mode, size_usd is 'max spend on buys, target proceeds on sells'; for basket mode, it's 'settlement notional — shares per leg, each paying $1 at resolution.' It also clarifies the side parameter's defaults and auto behavior in basket mode, which is not 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 starts with a specific verb+resource: 'Realizable-vs-theoretical edge check against live CLOB order-book depth.' It clearly distinguishes single-market mode from basket/partition mode and differentiates itself from siblings like polymarket_arbitrage and polymarket_edges by framing the check as a pre-trade validation tool.

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?

Explicit usage guidance is given: 'USE THIS before acting on any polymarket_arbitrage SELL/BUY-EVERY-LEG signal or any polymarket_edges trade above ~$500.' It also explains when to use each mode (single-market vs basket) and how to choose the side, making alternatives and exclusions clear.

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