List Delivery Slots

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds useful context that the data is the 'currently shown' checkout snapshot, but it does not disclose return format, pagination, or any other behavioral traits. The output schema covers return structure, so a mid-range score is appropriate.

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 a single, front-loaded, waste-free sentence. It immediately says 'Use this to read' and provides the essential scope without repetition or filler.

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 zero-parameter, read-only tool with an output schema, this description is complete. It tells the agent what the tool does, what scope the data represents, and the surrounding annotations plus output schema cover safety and return shape.

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 tool has zero parameters, so there is no parameter documentation burden on the description. The schema already fully covers this aspect; the description's reference to 'currently shown at checkout' reasonably anchors expectations about what the returned data represents.

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 clearly states a specific verb ('read') and resource ('delivery options currently shown at checkout'), which distinguishes it from sibling tools like select_delivery_slot and review_checkout. The scope is precise: it is a read-only listing of checkout-visible delivery slots.

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?

The description gives clear context: use it when you need the delivery options currently at checkout. It does not explicitly list exclusions or alternatives, but the sibling tool name select_delivery_slot strongly implies the contrasting selection use case, making the intended use reasonably clear.

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