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

The description effectively manages the severity indicated by the `destructiveHint: true` annotation by clarifying that the action is merely creating a DRAFT. It also explains complex calculations (totals computed here) and default behavior (currency, dates, template copying).

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 extremely dense but highly effective, packing the necessary structural, logical, and operational details into a concise block without filler.

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 complex financial tool involving templates, customer IDs, and calculation logic, the description is complete, covering both the input requirements and the resulting state (draft, non-sent).

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?

Since schema description coverage is 0%, the description excels by explaining the required object structure of the `items` array. It also clarifies logic for defaults (e.g., tax rate, currency, issue_date).

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 tool clearly states its purpose: to prepare an invoice draft for a specific customer. It distinguishes this creation action from the eventual delivery action, directing the agent to the sibling tool `send_customer_invoice`.

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?

It provides critical guidance on usage by stating explicitly that it only prepares a DRAFT and that no actual communication is sent. This prevents misuse and directs users towards the appropriate workflow.

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