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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds genuine governance context beyond them: draft status is not an approved commitment and proposed changes do not authorize line/rate/discount/due-date changes. This is useful behavioral framing for a read tool.

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 operative instruction ('Read the invoice before answering') is front-loaded, and the remaining sentences are compact governance constraints. Slight redundancy between the draft-status and proposed-changes warnings keeps it from a 5.

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 an output schema present, return values need not be explained, and rich annotations carry the safety profile; the description supplies the policy context an agent needs before quoting an invoice. It is largely complete, missing only explicit parameter or alternative-tool routing.

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?

There is one parameter (invoiceId) with 0% schema description coverage, and the description never mentions it or its expected form. With only one self-evident identifier the gap is minor, but the description does not compensate for the missing schema documentation.

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 clear verb+resource (read the invoice) and 'Quote only this record' implicitly scopes it to a single invoice rather than a collection like list_invoices. It does not explicitly name a sibling to distinguish itself from, so it lands at clear-but-undifferentiated.

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 usage directive ('Read the invoice before answering') but no explicit when-not or alternative-tool guidance, even though siblings like list_invoices, describe_line, and quote_line_rate could plausibly overlap. Usage is implied rather than scoped.

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