checkout_preview

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

Without annotations, description fully discloses that the tool charges nothing (safe, read-only) and describes behavior for error cases (order will be refused and requires cart fixes). No side effects are omitted.

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 sentences, each serving a distinct purpose: purpose, cost clarification, usage flow, error handling. No redundancy or fluff; well-structured and front-loaded.

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?

Given no parameters and the presence of an output schema, the description adequately covers what the preview contains and how to handle warnings. No missing context for a preview 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?

No parameters exist, so schema coverage is 100% and description adds no parameter info. Baseline for 0 parameters is 4, and no additional semantics needed.

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?

Description clearly states the tool previews the order including items, delivery fee, ETA, address, payment, and total. It is a specific verb-resource pair that distinguishes it from sibling tools focused on location, addresses, and products.

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?

Explicitly instructs to always run before confirming order, to show total to user and ask for confirmation, and details conditions (warning, available_for_checkout false, unavailable items) that require fixing the cart and re-previewing. Provides clear when-to-use and when-not-to-proceed guidance.

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