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

The description discloses the key behavior for the stripe_spt path: it settles a PaymentIntent, returns a signed license, and does not open a browser. However, it does not explain side effects for other payment modes, permissions, idempotency, failure behavior, or whether browser redirection occurs for non-SPT modes, which is significant for a payment tool.

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?

The description is two sentences with no filler. The first sentence names the action, and the second provides a specific mode detail. Every sentence earns its place and the most important clarifying behavior is 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?

Despite full schema coverage, the description is incomplete for a checkout tool with multiple payment modes. It only explains the stripe_spt special case and does not describe behavior for other modes, generic return values, error conditions, or whether a browser is normally opened. There is no output schema or annotations to compensate.

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 the baseline is 3. The description adds semantic value by specifying that payment_mode=stripe_spt, shared_payment_granted_token, and buyer_email must be used together to settle without a browser, which clarifies parameter relationships beyond individual schema descriptions.

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 identifies the tool as initiating checkout and provides a specific behavioral detail: with certain parameters it settles a Stripe PaymentIntent and returns a signed license. It does not explicitly contrast with sibling tools, though its function is distinct from quote/listing/preview tools.

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 implies when to use the tool (to start checkout) and gives a clear special-case usage for stripe_spt, but it provides no explicit guidance on when to choose this tool over alternatives or when not to use it. No exclusions or alternative tool references are mentioned.

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