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

Discloses the model (square-root size impact), calibration source (measured live fills), and supported order types. No annotations provided, so description compensates well but could mention if any side effects or authentication exist.

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?

Short and efficient, no redundant text. However, lacks structure for easy scanning (e.g., separating parameter details).

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?

Provides unit (bps) and floor cost ($0.01), and mentions calibration. But no output schema exists, and description does not specify return format or whether it's a single number or object. Partial coverage.

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?

Only order_type is partially explained with two values. No explanation for side, payment_signature, symbol, or notional_usd beyond what schema provides. With 0% schema coverage, description fails to compensate.

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 estimates realistic execution cost in bps for an order, with a floor of $0.01. It specifies calibration to SPY/QQQ and order type support, distinguishing it from pricing tools.

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?

No guidance on when or when not to use this tool compared to siblings like get_pricing or trade_preflight. No prerequisites or context provided.

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