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

Annotations already declare readOnly, idempotent, non-destructive, and openWorld=false. The description adds important behavioral context beyond annotations: about 98% return 'unknown' today, 'unknown' does not mean alive, each has an explanation, and the result includes an as_of date.

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 purpose and the critical unknown caveat, then adds use cases and alternative. It is slightly repetitive about the 25-register cap, which also appears in the title and schema, but overall remains efficient.

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, the description explains the return verdict and as_of date, warns about the dominant 'unknown' result, states the cap, identifies the alternative firma_profil, and notes no key is needed. This is complete enough for an agent to call 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%, and the single parameter is fully documented in the schema with format and maxItems. The description repeats the 25-register cap but adds no parameter semantics 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: checks up to 25 German companies and returns an alive/dead/unknown verdict with as_of date. It also distinguishes the tool from firma_profil, which provides full profiles, so an agent can tell them apart.

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?

Gives clear use cases (CRM data cleansing, checking a supplier list) and example user questions. It names firma_profil as the alternative for full profiles and states that no account or key is required, leaving little ambiguity about when to invoke it.

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