preview_limit_order

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

The description reveals critical behavioral traits beyond annotations, such as: the order is 'deliberately left unconfirmed, so it never reaches the market,' and the warning to read `on_market` because if true 'the order IS live.' It also discloses the commission dependency on order value and the gate requirement. This adds depth to the sparse annotations (readOnlyHint=false, idempotentHint=true).

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 organized into three compact paragraphs that each serve a purpose: the first states intent and usage, the second explains what happens and why, and the third adds a safety warning. No sentence is redundant, and the tool's complexity justifies the length.

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?

While parameter semantics are thin, the description covers the core aspects needed for safe invocation: purpose, when to use, expected response fields, a safety check (on_market), and the permissions gate. The presence of an output schema covers return structure, so the description doesn't need to list every field. However, a brief note on parameter meaning would make it fully self-contained.

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?

The input schema has no descriptions and schema description coverage is 0%, so the description must compensate. It does not provide any per-parameter definitions or constraints beyond what the schema already lists (symbol, side, quantity, price, order_id). Though it references 'order's value,' it does not explain how parameters interact or what each parameter means. This is a significant gap.

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 clear verb and resource: 'Ask Darwin what an order would cost, without placing it.' It distinguishes itself from the sibling tool place_limit_order by explicitly saying 'Use this before place_limit_order,' making the tool's purpose unambiguous.

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?

It provides explicit when-to-use guidance: 'Use this before place_limit_order, and whenever the user asks about commissions.' It also states that 'This is the only way to obtain commission figures,' ruling out alternatives, and notes the same DIRECTA_ENABLE_ORDERS gate as place_limit_order, which clarifies when it can be invoked.

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