invoices_email

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

With no annotations provided, the description carries the full burden of disclosure. It covers key behaviors: asynchronous sending via queue, PDF requiring Pro plan, optional attachments. However, it doesn't mention permissions needed, whether sending failure could occur, or audit/history visibility beyond what invoices_email_history implies. Generally transparent for an email-sending tool.

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 short sentences with zero waste. Front-loaded with the primary action, then workflow guidance, then behavioral notes. Every sentence 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?

Given 10 parameters and no output schema, the description does a good job covering the essentials. It covers async behavior, plan requirements, attachment options, and the defaults workflow. Minor gap: doesn't mention the response/return value or what success/failure looks like asynchronously, which matters for an email-send tool with queue processing.

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 100%, so the schema already documents all 10 parameters well. The description adds value by highlighting the relationship to invoices_email_defaults and noting defaults (PDF default true, XML default false) that affect parameter usage. The description reinforces the Pro plan requirement for attachPdf, beyond the schema's basic description.

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?

Clear verb+resource+scope: 'Send an invoice via email with optional PDF and XML attachments.' It distinguishes from sibling tools like invoices_email_defaults (which pre-fills) and invoices_email_history, and from delivery_notes_email/receipts_email which are for different document types.

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?

Explicitly instructs to use invoices_email_defaults first to get pre-filled subject/body, providing clear workflow context. Distinguishes the PDF attachment Pro plan requirement. However, it doesn't explicitly state when NOT to use this tool or name alternative tools beyond the defaults one.

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