Preview Order

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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds that the call yields expected fills and parameter validation, but does not say whether a preview reserves funds, consumes rate limit, or how validation failures are surfaced.

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?

A single front-loaded sentence with no filler; the purpose and the two things the caller gets back are stated immediately.

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?

For a complex nested order payload with no output schema, the description should say more about what a preview returns (validation errors? fill simulation? fee estimate?) and whether it is side-effect free. It hints at returns ("expected fills") but leaves the response shape and failure modes to inference.

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 nested order body documents every field (intent vs. outcomeSide+action, price required for limit orders, cashOrderQty for market orders). The description adds no parameter-level meaning beyond that, so the baseline 3 applies.

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 gives a specific verb+resource ("Preview an order") and adds scope: it happens "before submission" and returns validation results plus expected fills. It is clearly distinguishable from create_order, though it never names that sibling explicitly.

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?

"before submission to validate parameters" establishes a clear usage context and ordering relative to actually placing an order. It lacks an explicit exclusion (e.g., "does not place the order; use create_order for that") or prerequisites such as authentication or balance checks.

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