books_send_invoice_email

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

With no annotations, the description carries the full burden. It only states the action without disclosing side effects, requirements (e.g., invoice existence), or failure behavior. No details about what happens after sending or any state changes.

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, clear sentence with no redundant words. It is front-loaded and easily scannable.

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?

For a tool with no annotations, no output schema, and four parameters, the one-sentence description is insufficient. It lacks information about required inputs, email content customization, or potential side effects, making it incomplete for an agent to invoke 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 0%, so the description must compensate. It does not mention any of the four parameters (invoice_id, to_mail_ids, body, subject). While the parameter names are self-explanatory, the description adds no clarity about their roles, optionality, or constraints.

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 'Send an invoice via email' uses a specific verb 'Send' and resource 'invoice' with medium 'email', clearly stating the tool's function. However, it does not explicitly differentiate from sibling tools like books_email_credit_note or books_email_purchase_order, though the resource specificity implies the distinction.

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 provides no guidance on when to use this tool relative to alternatives such as books_email_credit_note or books_email_purchase_order. There is no mention of prerequisites, target scenarios, or excluded cases.

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