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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true. The description adds substantial behavioral context beyond this: it says the tool 'walks the ladder', lists exact return fields (top_of_book, vwap_fill_price, slippage_pp, shares_filled, max_fillable_usd, verdict), and warns about 'forced_directional_risk.' 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 front-loaded with the core purpose. Every sentence adds operational detail, yet the final sentence about 'dominant loss mode in real arb-bot P&L' is somewhat narrative and could be trimmed. The dense paragraph format could benefit from bullet lists for two modes, but it remains focused and scannable.

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 dual-mode complexity and lack of output schema, the description is thorough: it enumerates all return values for both modes, explains parameter semantics, provides usage thresholds, and describes the risk rationale. No important aspect is left unexplained.

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?

All 4 parameters have schema descriptions (100% coverage), so baseline is 3. The description adds significant extra meaning: it explains the market vs event mode distinction, clarifies that size_usd is interpreted as 'max spend on buys, target proceeds on sells' in single-market mode and as 'settlement notional' (shares per leg) in basket mode, and notes the default and clamp bounds. This goes well beyond 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 statement: 'Realizable-vs-theoretical edge check against live CLOB order-book depth,' which clearly distinguishes it from siblings like polymarket_arbitrage and polymarket_edges. It also explicitly names the two modes (single-market and basket), leaving no ambiguity about what the tool does.

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 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.' It also explains why (theoretical overround on thin books is not capturable, partial basket fills create unhedged directional risk), naming alternatives and giving a concrete threshold.

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