Apply wallet credit to invoice

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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the description needs only to add behavioral nuance. It adds that the payment can be partial ('part of') and uses wallet balance, but provides no details on side effects, failure conditions, or reversibility.

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?

A single, front-loaded sentence with no redundant wording. It states the action and funding source efficiently.

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?

Given the low complexity (2 params, no output schema) and the presence of annotations and complete schema coverage, the description provides sufficient context for the core operation. It could mention response behavior, but that is not critical for this simple payment action.

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 schema descriptions fully cover both parameters: invoice_number clarifies it expects a number not UUID, and credit_amount explains that omitting it applies the maximum. The description's 'part of' aligns with credit_amount but adds no further semantic detail.

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 uses the verb 'Pay' and specifies the resource 'invoice' and funding source 'client's wallet/credit balance', clearly distinguishing it from other invoice-related sibling tools like credit_invoice or refund_invoice.

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?

No explicit guidance on when to use this tool versus alternatives. It implies usage when a client wants to pay an invoice from wallet credit, but does not mention exclusions or compare against add_payment or refund_from_wallet.

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