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

The description discloses side effects well beyond the annotations: it warns that "sent" does not mean an email was delivered, and that submission may queue InvoiceNow delivery via PEPPOL and IRAS reporting depending on stored settings. For a destructiveHint=true, openWorldHint=true action this external-effect disclosure is exactly what the agent needs.

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?

Four sentences, front-loaded with the core action and its state semantics, then prerequisite, then side effects. Every sentence carries information, though the delivery/reporting sentence could be tightened slightly.

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?

With no output schema and only terse annotations, the description covers the action, its state meaning, prerequisites, external side effects, and a confirmation step. It is nearly complete for this destructive, open-world operation, leaving only return-value behavior unaddressed, which is not required.

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 67% and the schema already documents id, companyId, and the invoice fields. The description adds only the lineItems prerequisite, which concerns a different tool, and does not clarify the three actual parameters. Baseline 3 is appropriate.

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?

States a specific verb+resource ("Finalize a draft invoice and mark it as sent") and immediately clarifies the semantics of the resulting state. It differentiates itself from siblings like create-invoice-draft, preview-invoice, and update-invoice-draft by naming the draft workflow it completes.

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 gives a concrete prerequisite ("Requires lineItems to already be set via update-invoice-draft") and an explicit confirmation instruction, which is clear when-to-use context. It stops short of an explicit alternative/exclusion map beyond the prerequisite relationship.

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