get_checkout_url

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

Annotations already indicate this is not read-only (readOnlyHint=false) and not destructive (destructiveHint=false). The description adds context that the tool is a fallback for specific edits, revealing behavioral intent beyond annotations. No contradiction.

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 with no wasted words. The description front-loads the core purpose and immediately qualifies it as a fallback, followed by concrete usage examples and a prohibition.

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 simple tool with two parameters and no output schema, the description covers purpose, fallback nature, specific use cases, and when not to offer it. It lacks mention of the return format (a URL is implied) but is otherwise complete.

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 provides 100% coverage for both parameters, including detailed intent description. The tool description adds overall context but does not elaborate on parameter meaning beyond what the schema already conveys.

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 the tool provides a browser checkout URL for a cart and explicitly marks it as a fallback. It lists specific edit scenarios (swap payment method, opt out of credits, etc.), distinguishing it from sibling tools like preview_order and submit_order.

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 explicit usage guidance: 'FALLBACK ONLY' and 'Do not offer by default after previews.' It explains when to use (e.g., for edits CLI cannot make) but does not explicitly name alternative tools for other contexts.

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