payInvoice

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

No annotations provided, so description carries full burden. It discloses that this is a money-moving action and mentions the approval gate, but lacks details on side effects, results, or required permissions. Adequate but not comprehensive.

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?

Two sentences that are front-loaded with purpose and immediately followed by critical usage guidance. Every sentence adds value; no wasted words.

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?

Adequate for a simple payment initiation tool, but lacks explanation of output behavior, error handling, or what constitutes a valid payload. With a complex nested parameter (__userContext) not mentioned, completeness could be improved.

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 baseline is 3. The description only mentions 'using a payload' without adding meaning beyond the schema. Does not explain payload structure or __userContext which is detailed in schema.

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 states the verb 'initiate payment' and resource 'invoice' with the method 'using a payload.' It differentiates itself from sibling tools by emphasizing it is a money-moving action, but does not explicitly name alternatives.

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 states when to call: 'only call when the user explicitly authorizes payment for this specific invoice.' Also provides exclusion guidance: 'do NOT ask the user to re-confirm before calling' due to host enforcement. Does not mention alternative tools.

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