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

Beyond the annotations (read-only, idempotent), the description discloses extensive behavior: how it walks the ladder, what outputs to expect, the verdicts (clean|degraded|cannot_fill), and the critical nuance that partial basket fills convert an arb into an unhedged directional position. It also details per-mode semantics for size_usd, which is not in the 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 dense, with each sentence adding technical or usage value. It is structured into single-market and basket sections, with a final usage directive. However, a visual break or bulleted list would improve scannability, and some repetition (e.g., explaining size_usd twice) could be trimmed.

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 no output schema, the description fully lists the returned fields for both modes, including edge cases like thin_legs[], forced_directional_risk, and max_clean_notional_usd. It also covers the tool's role in the broader workflow (pre-trade risk check for arbitrage and edge signals), making it self-contained for an agent to decide when and how to invoke it.

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?

Even though schema coverage is 100%, the description adds semantic depth by explaining how size_usd is interpreted differently across modes ('max spend on buys, target proceeds on sells' vs 'settlement notional S (shares per leg)'). It also clarifies the auto-default behavior for side in basket mode, which enriches the schema definitions.

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 and resource: 'Realizable-vs-theoretical edge check against live CLOB order-book depth.' It clearly distinguishes this from siblings by defining two modes (single-market and basket) and naming the exact outputs, making the tool's function 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?

The description explicitly states when to use the tool: 'USE THIS before acting on any polymarket_arbitrage SELL/BUY-EVERY-LEG signal or any polymarket_edges trade above ~$500.' It names sibling tools, gives a threshold, and explains why (theoretical overround on thin books is not capturable), providing both positive and negative usage context.

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