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

Annotations only declare a non-destructive write (readOnlyHint=false, destructiveHint=false, openWorldHint=false). The description adds genuinely useful behavior beyond that: partial profiles are persisted rather than rejected, the response reports the missing fields, and outbound sending is gated on completeness. It does not cover auth/permissions or what happens to unspecified existing fields on edit.

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?

Purpose and behavior are front-loaded, and each semantic sentence (partial save, missing-field report, sending gate) earns its place. But the entire text is duplicated German/English verbatim, roughly doubling length without adding information for an agent.

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 9-parameter upsert with nested objects and no output schema, the description covers the important non-obvious behavior (partial-save + missing-field feedback loop, send gating) that an agent could not infer from annotations. The remaining parameter semantics are well covered by the 89% schema descriptions, so only minor gaps remain.

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 89%, so the schema already documents nearly every parameter (id, isDefault, disclaimer, rechtsform, etc.). The description only re-summarizes which fields are involved and adds no format or interaction detail beyond the schema; parameters such as id, isDefault and reasoning are not addressed in the description at all. Baseline 3 applies when the schema carries the load.

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+resource pair ('Legt ein Absenderprofil an oder bearbeitet es') and enumerates the covered fields (Rechtsform, Pflichtangaben, Bankverbindung, Haftungsausschluss, Briefpapier), so an agent immediately knows this is the write-side of the sender-profile family. It does not explicitly name the sibling tools it is not (get/list/validate), so it stops short of full differentiation.

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 gives real usage context — an incomplete profile is still saved and can be completed incrementally, and sending only works once mandatory details are complete — which tells the agent it may call this repeatedly with partial data. However it never names alternatives or exclusions (e.g. calling sender_profile_validate first to learn the required fields), so routing is implied rather than stated.

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