Get delivery slots

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

Annotations already declare readOnlyHint and openWorldHint, so the description's added value is the pagination/expansion behavior: without a date it returns the first two days in full plus just the dates of other days. That is exactly the kind of behavior an agent could not infer from the annotations, though return shape/naming is left implicit.

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 short sentences, each earning its place: purpose, default behavior, parameter usage, and next step. The default-behavior detail is front-loaded right after the purpose.

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 single optional-parameter read tool with annotations covering safety and no output schema, the description supplies everything needed to call it correctly in both modes and to route to the correct follow-up tool.

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 coverage is 100% with a format pattern, so the baseline is 3. The description adds real semantic constraint beyond the schema: the date should come from the list returned by a previous call, and omission is the default expansion mode.

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 ('List the delivery slots') plus its scope ('for the cart'), making it easy to tell apart from siblings like get_cart or select_delivery_slot.

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?

Explains both invocation modes (omit date vs. pass a date from the returned list) and names the follow-up tool with its trigger ('use select_delivery_slot once the user picked a slot'). It doesn't state prerequisites explicitly (e.g., that a cart must already exist), so it falls just short of a 5.

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