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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description usefully adds that line items, totals and balance are returned, but does not mention auth needs, error behavior for unknown ids, or pagination (not applicable here).

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, front-loaded sentences with zero filler: the payload contents come first, the underlying endpoint second. Nothing is wasted.

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?

No output schema exists, so the description reasonably compensates by naming the returned fields (line items, totals, balance). This is sufficient for a single-record read tool with one well-documented parameter, though it could note behavior on invalid ids.

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?

Only one parameter, fully documented at 100% schema coverage ('Invoiced credit note id.' with exclusiveMinimum 0). The description's 'by id' merely restates the schema; baseline 3 applies when the schema does the heavy lifting.

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 (get) and resource (credit note by id) plus what the response contains: line items, totals and balance. It is clearly distinguishable from sibling list tools like invoiced_list_credit_notes, though it does not name them explicitly.

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 phrasing 'One credit note by id' implies the fetch-a-single-record use case and contrasts implicitly with the list variant, but there is no explicit when-to-use, prerequisite, or named alternative. Usage is left to inference.

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