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

Annotations already mark the tool readOnly and idempotent; the description adds useful behavioral context by noting that every hit returns primary, asterisk, and additional codes with their official titles from the systematic index. There is no contradiction with annotations.

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 front-loaded with the core purpose, followed by explicit usage guidance and alternatives, making it easy to scan. It is slightly longer because of bilingual repetition between German and English, but the content remains purposeful and well organized.

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 search tool with four documented parameters and an output schema, the description covers the essential context: what to search for, what results look like, and which sibling tools to choose instead. It does not need to explain return values in detail because the output schema exists.

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%, so query, year, limit, and offset are already documented with descriptions, examples, defaults, and ranges. The description adds minor value by emphasizing German-language input and translation, but it does not need to compensate for missing schema documentation.

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 and resource: it searches the ICD-10-GM alphabetical index and maps clinical or colloquial diagnosis terms to ICD-10-GM codes. It also distinguishes itself from icd10_search and icd10_get, so an agent can tell text-based diagnosis search apart from code-lookup tools.

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?

It explicitly identifies when to use this tool: as the best first tool when the user asks to find diagnoses by text, symptom, disease name, colloquial German wording, or a partial term. It also names alternatives with the switching condition: use icd10_search when an ICD code is already known and icd10_get for the full entry of one code.

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