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

Annotations already cover the safety profile (readOnly false, destructive false, idempotent false, openWorld false), yet the description adds meaningful behavior beyond that: the invoice is a draft and unsent, it is auto-numbered in sequence, it uses saved business details, and free plans have a 3-invoice quota while paid plans are unlimited. This is exactly the kind of side-effect, quota, and post-condition context an 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?

Three tightly written sentences with the core action front-loaded and no filler. The quota sentence is relevant but slightly separated from the main behavioral statement.

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 create tool, the description covers the key behavioral traits an agent needs: draft state, auto-numbering, business detail reuse, and plan limits. Annotations carry the safety profile and the schema covers many parameters, so no critical gap remains, though more parameter context and an explicit alternative for sending would make it fully complete.

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?

The description does not discuss any of the 9 parameters, so it adds no meaning beyond what the schema provides. Schema description coverage is only 56%, leaving required fields like clientName and the items array without descriptive guidance in either place.

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 states a specific verb and resource — 'Create a draft invoice' — and adds scope ('in the signed-in person's TapTax') and a key distinguishing property ('created as a draft and is not sent'). This clearly separates it from siblings like send_invoice and mark_invoice_paid without requiring the schema to be opened.

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 clear context for when this tool applies: the invoice is created as a draft and is not sent. This implicitly routes sending to send_invoice, but no alternative tool is named explicitly and there are no stated exclusions or prerequisites beyond the free-plan quota note.

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