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

Annotations declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered by structured data. The description adds that the tool both verifies deliverability and returns a fee, but does not mention that delivery_provider and pickup_at affect the result, nor the failure case when a store does not deliver to the address.

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 sentences, no filler, with the core purpose front-loaded and the prerequisite tool chain following. Every sentence earns its place.

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?

A 12-parameter tool with a rich schema and an output schema, so the description does not need to explain return values. It covers purpose and workflow adequately; only the non-deliverable failure case and the effect of provider/subtotal parameters are unaddressed.

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%, so every parameter is already documented. The description adds no parameter-level detail beyond what the schema provides, which is acceptable when the schema does the heavy lifting.

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 (check) and two concrete resources (delivery coverage + estimated delivery fee). It is clearly distinguishable from sibling tools like kfc_stores and kfc_menu, which it explicitly names.

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 workflow: use kfc_nearby or kfc_stores first to find a store, then kfc_menu to inspect items. It orients the agent within the toolset but does not state when NOT to use it (e.g., pickup-only orders).

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