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

Annotations already mark this as destructive (destructiveHint=true), and the description adds meaningful context: the payment is executed from the linked wallet, it is constrained by caps, it is a two-step confirmation process, and it may return an approval link instead of executing. It does not detail reversibility or exact error conditions, but it goes beyond the annotation baseline.

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 compact sentences, front-loaded with the core action and then the two-step protocol and edge conditions. Every sentence contributes behavioral or usage information; there is no filler or repetition of 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 tool with destructive side effects and no output schema, the description covers the essential workflow, the preview fields returned, the confirmation flag, and the approval-link alternative. It could mention auth requirements or specific error payloads, but an agent has enough context to invoke it correctly.

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 description coverage is 100%, so the baseline is 3. The description adds value by explaining how url, confirm, and previewId interact: previewId comes from the initial call, confirm must be true only after user approval, and the url must be an HTTP 402 USDC challenge. This integrates the parameters into the workflow rather than just defining types.

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 action as paying an external x402 payment link from the user's Swop wallet, with a specific resource type ('https URL that returns an HTTP 402 USDC challenge') and scope ('within their caps'). This distinguishes it from sibling tools like swop_send while also referencing swop_send as a behavioral model.

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 prescribes a two-step workflow: call without confirm to preview, show the user the preview, get explicit consent, then call again with previewId and confirm: true. It also states the fallback behavior for over-cap or no delegation (returns a Swop-app approval link), giving clear when-to-use and alternative-route guidance.

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