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

Beyond the readOnlyHint=true annotation, the description adds valuable behavioral detail: gaps are reported as a result rather than thrown as errors ('Meldet eine Lücke als Ergebnis und läuft dabei durch'), and soft hints are returned as part of the response. This tells the agent the tool is non-blocking and safe to call even when data may be incomplete.

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 purpose and usage instructions are front-loaded, and the structure is logical: purpose, invocation pattern, accepted input variation, return fields, and non-blocking behavior. The full German/English duplication doubles the length, but each language block is internally tidy and the repetition is not excessive enough to obscure meaning.

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 two-mode validation tool with no output schema, the description covers everything an agent needs: what is checked, how to specify inputs, what is returned (valid, missingFields, soft hints), and how gaps are handled. The only minor nuance is that the schema makes proposedFields optional in the rechtsform branch while the description implies both are needed, but the description's 'exactly one form' guidance prevents ambiguity in practice.

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?

The schema provides oneOf structure but no per-property descriptions, so the description carries the semantic burden. It clarifies that profileId and rechtsform+proposedFields are mutually exclusive, that proposedFields is an object, and that a JSON-encoded object string is also accepted. This is precisely the kind of meaning an agent cannot derive from the raw JSON schema alone.

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 verb ('Prüft' / 'Checks') and resource ('Absenderprofil' / 'field set'), and clearly distinguishes the two validation modes: by profileId or by rechtsform + proposedFields. This makes it easy to tell apart from siblings like sender_profile_get or sender_profile_upsert, which have different verbs and resources.

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 explicitly instructs 'Gib genau eine Form an: profileId ODER rechtsform + proposedFields', telling the agent exactly which input combination to use. It does not explicitly name alternative tools or exclusion conditions, but the guidance is clear enough for correct invocation without cross-referencing siblings.

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