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

The description adds substantial behavioral context beyond the annotations (readOnlyHint, idempotentHint, non-destructive). It details the execution path: walks the order-book ladder, returns top_of_book, vwap_fill_price, slippage_pp, shares_filled, max_fillable_usd, and a verdict. It also warns about thin_legs and forced_directional_risk, which are non-obvious behaviors. No contradictions with the annotations are present.

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 well-structured, front-loaded with the core purpose and then organized by mode (SINGLE-MARKET vs BASKET). Every sentence adds relevant detail—parameters, return values, usage context, and failure modes. It is not overly verbose for the complexity of the tool, though it could be tightened without losing essential information.

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 absence of an output schema, the description thoroughly enumerates return values for both modes (top_of_book, vwap_fill_price, slippage_pp, shares_filled, max_fillable_usd, verdict; theoretical_sum, realizable_sum, capture_ratio, profit_usd, per-leg fill detail, thin_legs, max_clean_notional_usd, forced_directional_risk). It also covers parameter dependencies (market vs event), defaults, size interpretation, and the risk rationale. For a tool with 4 parameters and no output schema, this is comprehensive.

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 the baseline is 3. The description adds value beyond the schema by clarifying nuanced semantics for size_usd: 'max spend on buys, target proceeds on sells' in single-market mode and 'settlement notional S (shares per leg)' in basket mode. It also explains the default and auto-detection behavior for side in basket mode. This is helpful, though the schema already describes each parameter clearly.

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 pair: 'Realizable-vs-theoretical edge check against live CLOB order-book depth.' It clearly defines two operating modes (single-market and basket) and distinguishes itself from sibling tools like polymarket_arbitrage and polymarket_edges by naming them and specifying its role as a pre-trade check. This goes beyond a generic one-liner.

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 guidance is provided: 'USE THIS before acting on any polymarket_arbitrage SELL/BUY-EVERY-LEG signal or any polymarket_edges trade above ~$500.' It also explains why, noting that theoretical overround is not capturable on thin books and partial basket fills create unhedged directional positions. This gives the agent clear when-to-use and when-not-to-use context relative to alternatives.

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