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

Annotations already declare readOnlyHint=true and a matching title, so the safety profile is covered for free. The description adds nothing beyond that: no note on error behavior for missing ids, permissions required, or what a returned credit note contains. A getter this terse leaves the description earning almost no incremental credit.

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 words, front-loaded with the verb and resource, with zero filler. It is appropriately sized for a one-parameter getter, though it is arguably under-specified rather than genuinely optimized.

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 single-id read tool with full schema coverage and a readOnlyHint annotation, the minimum needed to call it correctly is present. There is no output schema, so nothing describes the return shape, and neither the id source nor error cases are covered in the description.

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%, and the schema itself documents the id and even points to billomat_list_credit_notes as the source. The description contributes no additional parameter meaning, so the 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 (Get) and resource (credit note) with a singular scope ('one') that implicitly distinguishes it from the sibling billomat_list_credit_notes. It never names or contrasts with any sibling explicitly, so it lands just short of 5.

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?

There is no when-to-use guidance, no mention of the required id coming from a list call, and no stated alternative to this tool. Usage is only inferable from the name and the 'one' scope.

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