Create a draft invoice

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

Annotations confirm it is a write operation (readOnlyHint=false) but do not mention side effects like counting towards a monthly maximum. The description adds useful behavioral context: number/language/texts/VAT come from account settings, the invoice is not sent, and it counts toward the plan's invoice limit. It does not contradict annotations.

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?

Three concise sentences, front-loaded with the core action, then scoping details. Every sentence carries useful information without redundancy.

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 covers high-level behavior and side effects, and an output schema exists (so return values need not be explained). However, with 8 parameters and only 25% schema coverage, the description omits parameter guidance entirely, leaving gaps for an agent to call it 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?

Schema description coverage is only 25%, so the description must compensate. It does not describe any parameters—not even the required customer_id or items. The schema has some descriptions, but the description adds no meaning beyond what little is there.

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 and resource ('Creates a draft invoice') and clarifies that the invoice is not sent. It implicitly distinguishes from update_invoice and record_payment by calling it a 'draft invoice', but does not explicitly name siblings or differentiate beyond that.

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 implies usage (creating a draft, not sending, counting towards limit) but provides no explicit when-to-use vs alternatives guidance. It does not mention when to use create_invoice instead of update_invoice or how it relates to sending an invoice later.

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