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

With no annotations, the description carries the full burden and does so well: it discloses payment location/actor, quote-vs-confirm behavior, idempotent retry via operation_id, amount bounds, and owner-only authorization. These are exactly the non-obvious traits an agent needs before calling.

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 dense sentences, all load-bearing, with purpose first and constraints last. No filler or redundancy with the schema.

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 payment tool with no output schema or annotations, the description is complete: it defines the flow, required inputs at each stage, retry behavior, amount range, and permissions. An agent can determine how to quote, confirm, and retry without external information.

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?

The input schema already covers 100% of parameters, but the description adds normative semantics: cents must be between 500 and 100000, operation_id comes from the quote and must be reused, and confirm gates actual execution. This goes beyond the schema's generic 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 states a specific action ('Open secure Stripe checkout') and resource ('prepaid hosting credit'), and adds that the owner completes payment in Stripe. This clearly differentiates it from general billing or pricing tools by its checkout-and-credit purpose.

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?

It gives an explicit two-phase workflow: omit confirm to quote, then confirm with matching cents and operation_id after approval, and reuse operation_id on retries. It doesn't name sibling alternatives or exclusions, so it's not a 5, but the invocation conditions are clear.

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