generate_invoice

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

With no annotations, the description carries full burden. It discloses that the tool automatically calculates VAT, embeds QR code data, and returns an XML string. This provides good insight into behavior, though it omits details like error handling or performance characteristics.

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 well-structured with a summary paragraph followed by an argument list. While lengthy, it is justified by the tool's complexity (17 parameters). The main purpose is front-loaded, but some redundant phrasing ('Creates a complete XML invoice') could be trimmed.

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?

Given the complexity, schema, and output schema, the description covers all parameters and the return type. It does not explain potential errors or edge cases, but for an AI agent generating invoices, the instructions are sufficient. The existence of an output schema mitigates the need for detailed output description.

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 coverage is 0%, so the description must compensate. It does so excellently by providing detailed explanations of all 17 parameters, including examples, types, and required conditions (e.g., 'buyer_vat' required for standard invoices). This adds significant meaning beyond the bare schema.

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 it 'Generate a ZATCA-compliant UBL 2.1 XML e-invoice' and lists supported invoice types (Standard, Simplified, Credit Note, Debit Note). This specific verb+resource combination distinguishes it from sibling tools like generate_qr_code, validate_invoice, etc.

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 it's for creating invoices but does not explicitly state when to use it versus alternatives (e.g., for signing or submitting, use other tools). No when-not or exclusion criteria are provided, leaving the agent to infer usage from context.

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