List invoices

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

The description discloses the read-only nature by saying 'List' and explicitly mentions what it does not do (paying). Combined with the readOnlyHint annotation, it is very transparent. It also specifies the information returned.

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 concise, consisting of two sentences. It front-loads the primary purpose and then adds a relevant boundary note, with no filler.

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 list operation, the description covers the core functionality and the return fields. It lacks details on pagination or error handling, but these are implied by the parameters and the nature of the operation. Overall, it is complete enough for an agent to use correctly.

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 parameter descriptions in the schema are self-explanatory, and the main description does not add additional meaning to the parameters. Since schema coverage is 100%, the description adds no extra parameter semantics, so a baseline score of 3 is appropriate.

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 action: 'List the account's invoices' and specifies the returned fields (amounts, dates, payment status). It also distinguishes the tool's boundary by noting that paying an invoice is out of scope.

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 gives a clear indication of when to use the tool (to list invoices) and explicitly mentions a non-goal (paying invoices). However, it does not explicitly contrast with other invoice-related tools like ws_invoice_get, though the name and context make it implicit.

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