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

Annotations already flag destructiveHint=true and idempotentHint=true, and the description adds context beyond them: the previous value is irretrievably lost (no history, no undo). It also discloses non-obvious timezone semantics for temporal properties, including that stored/output values are UTC and that sending UTC produces an offset. That is unusually rich behavioral disclosure.

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?

Front-loads the core action, then routing, then irreversible-loss warning, then timezone caveat — a sensible priority order with little waste. The mixed German/English and the trailing 'EN: object, record, entry, property, link, search' keyword tag are mildly noisy but conventional and do not obscure the payload.

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 destructive mutation tool with no output schema and full schema coverage, the description covers everything an agent needs: what it mutates, irreversibility, alternatives for other intents, and value-format/timezone behavior. No material gap remains.

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 100%, so key, udid, and value are already documented and the baseline would be 3. The description adds genuine meaning for the value parameter by explaining timezone interpretation and storage format for date properties, though scope_id is never mentioned and no added syntax is given for the core fields.

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 with exact scope: set or overwrite exactly one property of an object. It explicitly differentiates itself from siblings onto_object_update (multiple fields) and onto_object_delete_property (removal), so an agent can select it 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?

Gives explicit when-to-use ('gezielte Einzelkorrekturen') and names two alternatives with the conditions that select them: onto_object_update for several fields at once and onto_object_delete_property for removal. Nothing about routing is left to inference.

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