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

Annotations already declare readOnlyHint and non-destructive, but the description adds substantial behavioral context: it walks the order-book ladder, returns specific fields (top_of_book, vwap_fill_price, slippage_pp, verdict), and highlights risk of partial basket fills converting arb into directional exposure. It also clarifies required modes (market vs event) and default behaviors, going far beyond what annotations convey.

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 with REQUIRES, SINGLE-MARKET, and BASKET sections, front-loading the core purpose and using caps for the critical usage directive. It is dense and every sentence contributes, though it approaches the upper bound of length for a tool description; still, complexity justifies the size.

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?

With no output schema, the description carries full burden for return values and does so comprehensively: it lists all key outputs (theoretical_sum, realizable_sum, capture_ratio, profit_usd, thin_legs, max_clean_notional_usd, forced_directional_risk), covers edge cases like partial fills, and specifies default clamps for size_usd. It is complete for a complex financial tool with two distinct modes.

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, but the description enriches parameter meaning by explaining size_usd semantics per mode (spend vs target proceeds vs settlement notional), defaults, and the REQUIRES constraint for market/event. It clarifies side options for both modes and how default side is chosen in basket mode, adding value 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: 'Realizable-vs-theoretical edge check against live CLOB order-book depth.' It clearly distinguishes itself from sibling tools by referencing order-book depth and explicitly tying its use to polymarket_arbitrage and polymarket_edges signals, 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?

It 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 not capturable on thin books; partial fills cause unhedged positions) and distinguishes single-market vs basket modes as alternatives.

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