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

Annotations declare readOnlyHint=true, and the description extends this by revealing the internal algorithm: it splits the ID into three parts, recalculates the MOD 97-10 checksum, and detects transposition errors. It does not describe the exact output shape or error behavior, but for a read-only validator the added context is substantial.

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 description is one compact, front-loaded sentence. Every clause adds operational meaning, and there is no redundant restating of the tool name or title.

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?

The tool is simple (one string parameter, read-only) and the description covers the core behavior fully. The only minor gap is that, with no output schema, it does not explicitly state the return format, but the verbs imply both the decomposed components and the validation result.

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 coverage is 100%: the single leitweg_id parameter is already fully documented with a type and example. The description adds no parameter-level details, so it sits at the baseline 3 and does not need to compensate for schema gaps.

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 names a specific operation (Zerlegt) on a specific resource (Leitweg-ID) and further specifies the exact validation logic (MOD 97-10, digit transpositions). This makes it clearly distinguishable from the sibling tools, which concern invoices, VAT, and customer searches.

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 intended use is implied: call this tool when a Leitweg-ID needs to be decomposed and checksum-validated. However, the description gives no explicit when-not-to-use guidance or comparison to siblings such as fehler_erklaeren or rechnung_pruefen, so usage guidance is only implicit.

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