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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=false, so the safety profile is known; the description adds the ordering dependency, which is genuinely useful context. It does not say whether calling it again replaces prior delivery settings, whether it clears existing cart items, or what happens if a conflicting deliveryType is supplied — meaningful gaps for a cart-state mutation.

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?

Two short sentences with zero padding; the purpose is stated first and the prerequisite clause immediately follows. Nothing is repeated from the title or schema.

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?

An output schema exists and the schema fully documents parameters, so the description need only carry purpose and flow position — both are covered. The remaining gap is the interaction between delivery selection and existing cart contents, which an agent would want to know before re-invoking.

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 every one of the 11 parameters including the deliveryType enum and the home-delivery conditional requirements is already documented in the schema. The description adds no parameter-level meaning beyond that, so the baseline 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 opens with a specific verb+resource pair ("Set cart delivery type and delivery details") that maps directly to the tool name, so an agent immediately knows this configures delivery on the active cart. It does not distinguish itself from the related delivery_availability_check sibling, but the sequencing clause makes its role in the cart flow evident.

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?

"This must be called before listing product prices or adding products to cart" is an explicit prerequisite that tells the agent exactly where this step sits relative to other cart tools. There is no statement of when-not to call it (e.g., whether it can be re-called to change an existing delivery selection) or mention of delivery_availability_check as an alternative for feasibility questions.

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