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

Annotations already indicate read-only, idempotent, non-destructive behavior. The description adds value by detailing the check against live order-book depth, ladder walking, and the specific outputs (top_of_book, vwap_fill_price, slippage_pp, etc.). It also discloses behavioral traits like forced directional risk and the dominant loss mode.

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 (about 150 words) but every sentence is purposeful. It uses bold caps for modes and clear separators, which aids readability. Minor improvement could be using bullet points for return fields, but the current structure is acceptably organized and front-loaded with the core purpose.

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 complexity (two modes, multiple return values), the description is complete. It explains both modes, lists key return fields, and covers critical failure modes (thin legs, forced directional risk). No output schema exists, so the description must explain return values, which it does adequately. The warning about partial fills is crucial and well-provided.

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 parameters are already described. The description adds context beyond the schema: explains how side defaults differ in modes, clarifies size_usd interpretation for single-market vs basket, and details the differences between 'market' and 'event' parameters. This additional context enhances understanding but the schema already does most of the work.

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 clearly states it performs a 'realizable-vs-theoretical edge check against live CLOB order-book depth' and distinguishes between single-market and basket modes. It explicitly separates itself from sibling tools by advising to use it before acting on polymarket_arbitrage or polymarket_edges signals.

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 guidance: 'USE THIS before acting on any polymarket_arbitrage SELL/BUY-EVERY-LEG signal or any polymarket_edges trade above ~$500.' It explains the rationale (theoretical overround on thin books is not capturable) and warns about the risk of partial basket fills converting arb into a directional position.

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