list_invoices

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

With no annotations provided, the description must carry the behavioral disclosure burden. It states that the tool lists all invoices, which implies a read-only operation, but it does not disclose potential side effects, pagination, rate limits, or return format. While 'List' conveys a safe read action, the lack of explicit behavior beyond that leaves some gaps.

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, front-loaded sentence: 'List all invoices, optionally filtered by account.' Every word contributes to the purpose, with no filler or redundancy. It is optimally 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?

The tool is simple with one optional parameter and no output schema. The description covers its core purpose and filter capability, which is sufficient for a basic list operation. It could benefit from mentioning response characteristics or scope verification, but given the low complexity, the description is largely 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 description coverage is 100% because the 'account' parameter has a description ('Account id filter'). The tool description merely echoes this ('optionally filtered by account') without adding further contextual meaning such as value format, requiredness aside from optionality, or behavior when omitted. This meets the baseline for high schema coverage.

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 states a specific verb ('List') and resource ('invoices'), clearly indicating the tool's function. It distinguishes from siblings by showing it retrieves multiple invoices ('all invoices') while get_invoice implies a single invoice and send_invoice implies a different action.

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 provides clear context for when to use the tool (listing invoices, with optional account filtering), but it does not explicitly mention when not to use it or name alternatives. The sibling tools are distinguishable by their names and descriptions, but the description itself lacks direct exclusions or alternatives.

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