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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, and openWorldHint=false, so the safety profile is covered. The description adds one genuinely useful non-annotation fact: the invoices:write scope requirement. It does not, however, warn that the operation is non-idempotent, i.e. that submitting the same invoice_number twice may create duplicates.

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?

Two short sentences with zero filler, and the core purpose is front-loaded ahead of the scope requirement. Nothing should be removed.

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 annotations covering safety and the schema fully documented, the description is minimally sufficient. Gaps remain for a non-idempotent create with no output schema: it never says whether the created invoice (and its ID) is returned, nor how duplicate invoice numbers are handled.

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 100% across all 14 parameters, so the schema carries the parameter documentation. The description adds nothing about the three required fields, the status enum, or the UUID-typed foreign keys, so baseline 3 applies.

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 and resource ('Create a new invoice'), which is unambiguous on its own. It does not distinguish this from sibling creation tools such as create_expense or create_purchase_order, and there is no create_invoice sibling collision to resolve, so sibling differentiation is absent but not needed.

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 gives no when-to-use guidance, no prerequisites beyond the auth scope, and no indication of how this differs from other financial-creation tools. An agent must infer usage purely from the name.

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