Select delivery slot

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

Adds value beyond annotations by disclosing the return content (selected delivery window and cart total) and the key behavioral limit that no order is placed. Idempotency and non-destructiveness are already covered by annotations, so only the omission of what happens when an existing slot is re-selected keeps this from a 5.

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?

Three short sentences, each with a distinct job: what it does, how to source the argument, and what it returns plus what it does not do. Scoping constraint is front-loaded and there is no 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?

With a single required parameter, no nested objects, and no output schema, the description supplies everything needed: valid input source, precondition, return values, and the boundary against order placement.

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% and the parameter already carries a description, so the baseline is 3. The description earns extra credit by restating the provenance constraint on slotId (must come from get_delivery_slots), which prevents fabricated IDs.

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 object ('Choose when the cart is delivered') and explicitly bounds the scope with 'This does not place an order,' which separates it from a checkout tool. The reference to get_delivery_slots makes the sibling relationship unambiguous.

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?

Gives an explicit precondition: only use a slotId from get_delivery_slots, after the user picked the slot. That names the alternative tool to call first and the user-confirmation condition, leaving nothing to inference.

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