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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is covered. The description adds valuable behavior beyond annotations by specifying that primary, star, supplementary, and second primary key numbers are all considered. It does not discuss empty-result or error behavior, but the output schema and annotations reduce the burden.

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 compact, informative, and front-loaded with the core purpose. The German and English versions partially duplicate each other, but the bilingual structure is deliberate and the key technical detail about key-number types is included without padding.

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 read-only reverse lookup with two well-documented parameters, an output schema, and a clear use case, the description is complete. It covers the essential behavior, scope of results, and practical usefulness, leaving no critical gap for an agent to invoke it correctly.

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%, so both parameters ('code' and 'year') are already documented with format and default semantics. The description only restates the general purpose of the code parameter and adds no format, constraint, or interaction details beyond the schema, which is the expected baseline.

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 clearly states a specific verb ('Liefert') and resource ('Einträge des Alphabetischen Verzeichnisses'), and defines the operation as a reverse lookup from an ICD-10-GM code to the index terms referencing it. This distinguishes it from the search-oriented sibling icd10alpha_search without requiring schema inspection.

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 description gives clear usage context: use this tool when you have a code and want to know which clinical or everyday terms lead to it. It does not explicitly name alternatives or exclusion conditions, but the reverse-lookup framing makes the intended scenario obvious.

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