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

Annotations already declare destructiveHint=true, idempotentHint=true, and openWorldHint=true, so the safety profile is covered. The description adds real behavioral context beyond them: the token must be scoped to at least the order amount in USD, and the outcome ("the order is paid and goes to print"). It stops short of error/failure behavior.

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 tight sentences with zero waste. The action and its token requirement are front-loaded, followed by the outcome and the approval precondition.

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 two-parameter mutation tool whose safety traits are already carried by annotations and with no output schema required, the description covers purpose, prerequisite, and outcome adequately. Minor gap is the absence of any failure/decline handling context.

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 50%: shared_payment_token already has a schema description, but the description adds the meaningful scoping constraint ("at least the order amount in USD") and the approval provenance. order_id, however, is undocumented in both schema and description, so the description does not fully compensate for the coverage gap.

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+resource ("Pay for an unpaid order") and scopes it with the qualifier "unpaid," plus names the required payment token. This cleanly distinguishes it from siblings like cancel_order and get_order without needing to open any schema.

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: "Use only after the user approved the purchase," reinforced by "a Stripe shared payment token (spt_…) the user approved." The when-to-use condition is unambiguous, and the approval gate acts as the when-not.

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