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

Annotations already declare non-read-only, idempotent, non-destructive behavior, and the description adds useful context: empty call returns current state, populated call changes fields, and roles are not modified. It does not fully explain partial-update semantics when only some fields are supplied.

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 core German description is dense and front-loaded with the key read/change distinction. The appended English keyword string is irrelevant to profile operations and does not earn its place.

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 five-optional-parameter tool with no output schema, it explains the read/update behavior and role boundaries well enough to call correctly. It still leaves partial-update and return-value specifics implicit, and the file/upload keywords blur capability boundaries.

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 the schema already documents all five parameters. The description lists the same fields but adds no format details, constraints, or partial-update behavior, making the baseline 3 appropriate.

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 first sentence clearly states that this reads or changes the user's own profile fields, and it distinguishes own-profile work from role and foreign-profile operations. However, the trailing English keywords 'file, upload, document, attachment' are unrelated and can mislead about the tool's purpose, so it is not a clean 5.

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 explicit when-to-use guidance: own profile data, no fields for reading, fields for changing, and it excludes role changes and foreign profiles. The named alternatives onto_user_update and onto_user_update_profile do not appear in the provided sibling list, which reduces actionability.

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