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 substantial context beyond annotations: it details what the tool calculates (top_of_book, vwap_fill_price, slippage_pp, shares_filled, verdict, capture_ratio, forced_directional_risk, etc.), how size_usd is interpreted in each mode, and the risk of partial basket fills converting an arb into directional position. 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 dense and well-structured, front-loading the core purpose and then alternating between single-market and basket details. It is fairly long but every sentence carries essential information given the tool's two modes and many return fields. It could be slightly more concise by eliminating minor repetition, but overall it is organized for readability.

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, multiple parameters, rich return values), the description is remarkably complete. It explains output fields, parameter semantics, usage timing, potential risks, and limitations. With no output schema, the description carries the burden of conveying what the tool returns, and it does so thoroughly.

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% and the schema documents each parameter's basic role. The description adds significant meaning: it explains the two modes (`market` vs `event`), the default behavior of `side` in basket mode (auto based on partition sum), and the distinct interpretation of `size_usd` in single-market vs basket mode (spend/proceeds vs settlement notional per share). This exceeds the baseline.

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 the tool's purpose: 'Realizable-vs-theoretical edge check against live CLOB order-book depth.' It uses a specific verb ('check') and resource ('CLOB order-book depth'), and distinguishes between single-market and basket modes. It also references sibling tools (polymarket_arbitrage, polymarket_edges) to position its unique role, making it easy to differentiate.

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 explains the context and rationale, including why theoretical overround on thin books is not capturable and how partial fills create unhedged directional risk. This clearly states when and why to use this tool over alternatives.

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