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

Annotations only declare readOnlyHint=true, so the description carries the rest and does so well: it discloses the returned contents (status, line items, totals, related invoice), the presence of a lexwareAppUrl deep link, and the underlying GET /v1/credit-notes/{id} call. No auth, rate-limit, or error/404 behavior is mentioned, which keeps it short of a 5.

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, front-loaded with the verb and resource, with the return fields listed compactly. The trailing 'GET /v1/credit-notes/{id}' restates the tool name/resource somewhat redundantly, but everything else earns its place.

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 no output schema in play, the description's enumeration of returned fields is exactly the compensating detail needed, and the single-parameter surface keeps the scope small. The main gap is that it never says what to do if the id is invalid or where the id comes from within the description itself.

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% with a single required 'id' parameter, so the baseline is 3. The description only restates 'by id' and adds no format, provenance, or lookup detail beyond what the schema already provides.

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 ('Get one credit note by id') and enumerates the payload it returns (status, line items, totals, related invoice). It is self-evidently distinct from the other get_* siblings by resource name, but it never explicitly names an alternative or clarifies why you'd want a credit note versus an invoice or quotation.

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 'by id' phrasing implies a lookup-after-listing workflow, but there is no explicit when-to-use/when-not-to-use guidance and no reference to lexware_list_vouchers (which the sibling schema mentions as the source of ids). An agent must infer the routing itself.

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