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

Annotations already declare non-read-only, non-idempotent, non-destructive. The description adds real behavioral value beyond that: the result is a draft, no rental or charge occurs, and the backing endpoint (POST /baskets.api) is disclosed. It omits what happens on duplicate calls, which matters given idempotentHint=false.

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?

Four tight sentences: what it creates and its state first, the conditional parameter second, the negative scope third, the endpoint last. No filler and the most decision-relevant facts are 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 7-parameter creation tool with no output schema, the description covers scope, draft state, and side-effect exclusions well. It does not say what the call returns (presumably the new order id), which is the main remaining gap since no output schema exists.

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 the baseline is 3. The description only adds a conditional hint for business_id ('If the customer belongs to several businesses'), which closely mirrors the schema text, and gestures at optional assets and dates without new syntax detail.

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?

States a specific verb and resource ('Create a new rental order') plus the lifecycle state it lands in ('a draft until it is booked or rented out'). This cleanly separates it from sibling tools like book_order, rent_out_order, and record_order_payment.

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?

Explicitly frames when to use it (customer with optional assets and dates, business_id when the contact spans businesses) and when not to: 'Does not rent anything out and does not charge.' It stops short of naming the sibling that does those things, so the agent must infer book_order/rent_out_order.

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