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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), yet the description still adds real context: the cart is anonymous and requires no auth, the confirmation link is one-time and only present while open, and lines are re-priced from the live menu. That conditional-field behavior is exactly the kind of trait structured fields cannot express; only error behavior for an unknown cart_id is missing.

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 opening with the verb and key parameter, followed by the return payload in a compact parenthetical. Dense but every clause carries information; only the parenthetical listing is slightly close-packed for scanning.

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?

With no output schema, the description properly carries the return-value burden by naming each field and its conditional availability, and it flags the no-auth requirement. What it omits is failure behavior for an invalid or expired cart_id, which matters for a lookup keyed on a caller-supplied id.

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 burden falls on the description, which only qualifies cart_id as identifying an anonymous cart. It does not say where the cart_id comes from (presumably create_cart) or how to handle an unknown/expired id; the 32-hex format, however, is already enforced by the schema pattern.

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 ('Read an anonymous cart by cart_id') and then enumerates exactly what a read yields: state, confirmation link, re-priced lines, and order id. This distinguishes it from create_cart and get_order_status without the agent needing to open any schema.

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?

Usage is implied by the lifecycle vocabulary (open/consumed/expired) and by the 'anonymous cart' scope, so an agent can infer this is the lookup for a guest cart before confirmation. However, no sibling is named and there is no explicit when-not guidance (e.g., use get_order_status once an order id exists), leaving routing to inference.

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