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

Beyond the readOnlyHint annotation, the description adds valuable behavioral detail: it performs validation and sizing, shows a proposal card, and is 'always safe to call.' This discloses side-effect-free behavior and the user-facing outcome without contradicting any annotations.

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?

Three concise sentences, each serving a clear purpose: when to use, what it does, and what to do next. There is no redundancy or filler, and the most important directive is 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?

For a tool with 9 parameters and no output schema, the description adequately covers the tool's role, its safety profile, and its interplay with place_order. It also tells the agent what the user sees (proposal card), making the tool fully usable from the description alone.

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%, so all 9 parameters are already documented in the schema. The description adds context about validation/sizing but does not provide per-parameter meaning beyond what the schema gives, so the baseline score of 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 uses a specific verb ('preview'), names the resource ('order'), and clearly states that it validates and sizes an order WITHOUT placing anything. It explicitly distinguishes itself from place_order, so an agent can instantly tell what this tool is for.

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 explicitly says to use this tool BEFORE place_order whenever the user wants to open a position, and it directs the agent to call place_order with the same arguments if the user confirms. This gives both a clear usage condition and an explicit alternative.

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