Stream

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

No annotations are provided, so the description carries full burden. It mentions the action ('(Re)send') and delivery methods, but lacks critical behavioral details: whether this triggers notifications, requires specific permissions, has rate limits, or what happens on failure (e.g., retry logic). For a communication tool with zero annotation coverage, this is insufficient.

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, efficient sentence with zero waste. It's front-loaded with the core action and resource, and every word ('(Re)send', 'invoice', 'customer', 'email / SMS') adds value. No extraneous details or repetition.

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 1 parameter, no annotations, but an output schema exists, the description is moderately complete. It covers the purpose and delivery methods, but lacks behavioral context (e.g., side effects, error handling) and parameter details. The output schema may handle return values, but for a tool that likely involves external communication, more guidance is needed.

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 doesn't mention the 'invoice_id' parameter at all, leaving it undocumented. However, with only 1 parameter, the baseline is higher; the description implies the tool operates on an invoice but doesn't explain parameter meaning or format. This is minimal but not entirely absent.

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 the action ('(Re)send') and target resource ('an invoice to the customer'), specifying the delivery methods ('via email / SMS'). It distinguishes from sibling tools like 'create_invoice' or 'void_invoice' by focusing on communication rather than creation or cancellation. However, it doesn't explicitly differentiate from all siblings (e.g., 'mark_payment_as_paid' might also involve notifications).

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 explicit guidance on when to use this tool versus alternatives is provided. The description implies it's for sending invoices, but doesn't specify prerequisites (e.g., invoice must exist, customer contact info required) or when not to use it (e.g., if invoice is voided). It mentions 'resend' but doesn't clarify scenarios for initial send vs. resend.

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