pay_invoice

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

Annotations already indicate destructive hint (mutation). The description adds that the tool returns a deep link and requires confirmation, informing the agent of the behavioral outcome beyond the annotation.

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, no wasted words. Front-loaded with purpose and immediately provides key behavioral details. Perfectly concise.

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 3 params and no output schema, the description covers purpose, behavioral caveat, and a parameter requirement. It could mention what the deep link entails but is sufficiently complete.

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 has 100% coverage, so baseline is 3. The description adds crucial constraint on the confirm parameter ('Requires confirm:true'), adding value beyond the schema's description.

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 tool pays an invoice from a vendor, which is a specific verb+resource. It distinguishes from siblings like get_workspace or sign_contract by focusing on payment.

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 mentions the requirement 'confirm:true' and notes that v1 returns a deep link instead of headless payment, providing context for usage. However, it lacks explicit when-not or alternative tool comparisons.

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