get_invoice

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

No annotations are provided, so the description carries full burden. It makes clear this is a read-only retrieval operation ('Get full details... Returns all entries'), which implies non-destructive behavior. However, it doesn't disclose the return format structure, pagination, or error behavior, though the presence of an output schema reduces the burden somewhat.

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 well-organized with a clear opening summary followed by Args documentation. It's compact—two paragraphs plus parameter notes. The only minor inefficiency is the slightly redundant phrasing in the Args section, but it's largely front-loaded and earns its place.

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?

With an output schema present, the description needn't explain return values. The two parameters are both well-documented. For a simple retrieval tool with an output schema, the description covers purpose, dual-resource scope, parameter nuance (GUID vs human ID, owner_type disambiguation), which is reasonably complete. Could note what happens without owner_type but that's a minor gap.

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 0%, so the description must fully compensate. It does: 'id' is explained as the human-readable ID (e.g., '000001') rather than internal GUID, and owner_type is explained with the 'customer' vs 'vendor' mapping and the rationalization for why filtering matters (independent counters). This adds significant meaning beyond the bare 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 ('Get full details'), the resource ('invoice or bill'), and the scope ('including line items'). It explicitly distinguishes itself by covering both customer invoices and vendor bills, distinguishing from sibling get_invoice-like operations. The 'Returns all entries with quantities, prices, and totals' adds concrete detail about what the tool retrieves.

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 explains that it works for both customer invoices and vendor bills, and the owner_type parameter rationale (independent counters for invoice vs bill) gives clear context on when that parameter matters. However, it doesn't explicitly state when-not-to-use or explicitly name alternatives like list_invoices for enumeration, though the context is clear enough.

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