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

Annotations declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, destructiveHint=false. The description adds substantial behavioral context beyond these: it explains order-book walking, the verdict categories (clean|degraded|cannot_fill), the outputs (top_of_book, vwap_fill_price, slippage_pp, shares_filled, etc.), and warns about forced_directional_risk and thin_legs. Nothing contradicts the annotations; it enriches them.

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?

Although the description is long, it is tightly structured with mode-specific sections and every sentence carries operational value. The first line states the core purpose, and the rest is organized around single-market, basket, and usage context. There is no filler; for a tool of this complexity, the length is appropriate and front-loaded.

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 fully enumerates return fields and verdicts, covers both modes thoroughly, explains the risk of partial basket fills, and ties the tool to specific upstream signals (polymarket_arbitrage, polymarket_edges). It leaves no significant gap for an agent to understand when and how to invoke it correctly.

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% with already-detailed param descriptions. The description goes further by clarifying size_usd semantics in single-market mode ('max spend on buys, target proceeds on sells') versus basket mode ('settlement notional S — shares per leg; each share pays $1'), and explains the side default logic for basket mode. This adds interpretive meaning beyond the schema alone.

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 this from sibling tools by emphasizing fill risk and realizable versus theoretical edge, and it enumerates two distinct modes (single-market and basket). This is far more specific than a generic purpose statement.

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 also explains why the tool is necessary (theoretical overround is not capturable on thin books) and describes the dominant loss mode. This is a model of when-to-use guidance.

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