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

Annotations already flag destructiveHint=true and idempotentHint=true, but the description adds the concrete consequence the agent actually needs: the prior value is gone, no history, no undo. The timezone/UTC semantics are genuine behavioral context beyond structured fields. It falls short of 5 because the destructive detail and the long ZEITREGEL block partly restate the schema's value description and are buried among irrelevant siblings.

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 purpose, alternatives and undo warning are correctly front-loaded, which is the strongest part. But the tail is padded: English keyword soup ('object, record, entry, property, link, search') and a time-operator list (minutes_of, minutes_between, hours_between) that has no bearing on setting a single property, plus a timezone rule repeated twice.

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 4-parameter mutation with annotations covering safety and no output schema, the description covers the essentials: scope, alternatives, irreversibility, and the UTC storage convention. What is missing is the role of scope_id and what a success response returns, but neither is critical to invoking 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%, so udid, key, value and scope_id are all documented in structured data; that establishes the baseline of 3. The description adds no meaning for scope_id (whether it scopes the object lookup or the property definition) and none for key format, and its timezone note duplicates the schema's value description rather than extending it.

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 opening sentence names a specific verb ('setzen oder ueberschreiben') and pins the exact scope: exactly ONE property of an object. It also explicitly contrasts with the two nearest siblings (onto_object_update for multiple fields, onto_object_delete_property for removal), so the agent can discriminate this tool without opening any schema.

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 states the positive case ('gezielte Einzelkorrekturen'), explicitly routes bulk edits to onto_object_update, and routes deletion to onto_object_delete_property. Both the when and the when-not plus the named alternatives are present, with nothing left to inference.

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