get_invoice

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

No annotations are provided, so the description must communicate behavioral traits. It only states the fetch action, which is read-only, but does not disclose any error handling, return format, or side-effect concerns, adding little beyond the name.

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?

The description is a single, clear sentence with no unnecessary 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?

For a simple single-fetch tool with one parameter, the description is functional but leaves out details about return values or error conditions, especially given no output schema.

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 already provides a full description of invoiceId ('Invoice id, e.g. inv_2214') with 100% coverage, so the description adds no additional parameter semantics beyond the 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 uses the verb 'Fetch' and specifies the resource 'single invoice by id', clearly distinguishing it from sibling list_invoices that fetches multiple invoices.

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?

The description does not explicitly state when to use this tool versus list_invoices, though the 'single invoice by id' phrasing implies retrieval of one specific invoice. No alternatives or exclusions are mentioned.

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