Invoices

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

With no annotations, the description carries full burden and does disclose two behaviors that matter: it requires an API key owned by an organization admin, and it is read-only ('Reads only'). It omits pagination, billing period scope, and result limits, but the auth and safety profile are covered.

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 compact sentences with the resource identified first and constraints trailing. The em-dash clause 'the billing record the usage reconciles against' is slightly indirect but carries real information about the tool's role.

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?

No output schema and no parameters, so the description must convey what comes back: it names invoices and their line items, plus the auth prerequisite. It stops short of stating time-range or pagination behavior, which is the only remaining gap for a zero-parameter read tool.

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 tool takes zero parameters, which is the baseline-4 case. The schema is empty, so there is nothing for the description to clarify or compensate for.

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?

States a specific resource ('your organization's invoices with their line items') and a verb-like operation implicitly (retrieval/read). An agent can distinguish it from ideogram_usage and ideogram_quote, though the description never names those siblings to sharpen the boundary.

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 clause 'the billing record the usage reconciles against' implies this is used alongside ideogram_usage, giving implied context rather than an explicit when-to-use/when-not or named alternative. No exclusions or prerequisites beyond the auth note.

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