Invoice summary

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

With no annotations, the description carries the full burden of disclosing side effects, but it never states whether this tool creates an invoice, modifies time entries, or is read-only. The phrase 'Turn tracked billable time into invoice line items' implies a transformation rather than a safe summary, leaving the mutation status ambiguous.

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 sentence with no filler; the core operation and output fields are front-loaded, and the currency example adds concrete value. Every clause 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?

The description partially substitutes for a missing output schema by listing what the line items contain, but it leaves out essential context: whether calling this tool mutates any state, how the output is grouped or structured, and how it relates to invoice_create or invoice_from_hours. For a four-parameter, annotation-free tool, this is adequate but not 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%, so the schema already documents project, from, to, and unbilled_only. The description maps 'project or client' to the project parameter and describes output fields, but it adds no additional meaning to the input parameters beyond what the schema provides.

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 identifies a specific operation—turning tracked billable time into invoice line items—and enumerates the output fields: hours, hourly rate, amount per task, and total. It also adds a concrete currency behavior. However, it does not explicitly distinguish this summary tool from siblings like invoice_create or invoice_from_hours, and 'turn into line items' could be misread as actually creating an invoice.

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?

No when-to-use or when-not-to-use guidance is provided. The description does not name alternatives such as invoice_from_hours or invoice_create, and it never states whether this should be used as a read-only preview before invoicing.

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