preview_order

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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description reinforces 'WITHOUT sending it' without contradicting anything. It adds useful behavioral detail: guardrail validation, single-use confirmation_id, and expiry/order-type constraints, going beyond the annotation coverage.

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 four tight sentences with the core behavior front-loaded first. Every sentence adds a distinct piece of information: non-sending behavior, parameter rules, and the produced confirmation_id. No filler exists.

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 10-parameter validation tool, the description covers the main conditional relationships needed to form a valid call. It does not explain exchange or sell_fractions semantics, but these are reasonably inferable from the schema, and the output schema handles return details. The description is strong enough for an agent to invoke correctly in most scenarios.

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 0%, so the description must compensate. It does for the most confusing parameters: size allows fractions, limit_price is required for limit, stop_price for stopMarket, expiry gtd needs expiry_date, and market orders only support gfd. A few self-explanatory params (isin, side, exchange, sell_fractions) are left to the schema, but the critical conditional semantics are covered.

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 states a clear verb ('Validate an order') and resource, and explicitly contrasts with sending it via place_order. It also names the output artifact (single-use confirmation_id), making the tool's role 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 makes the intended usage obvious: validate against guardrails without sending, then use the returned confirmation_id with place_order. It does not explicitly list when not to use it, but the context strongly implies it is the pre-send check sibling to place_order.

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