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

Annotations already declare readOnlyHint=false, destructiveHint=false and idempotentHint=true, so the safety profile is covered. The description adds real value beyond that with 'Aendert das Modell' and, importantly, 'Bestehende Objektwerte aendert es nicht' – scoping the blast radius of a mutation. It does not say what happens when the key already exists, despite the idempotent hint.

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?

Three short sentences, front-loaded with the action and the model-change warning. The trailing '| EN: property, field, schema, property set, definition' keyword tag is search padding rather than semantic content, which is the only waste.

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 10-parameter mutation with full schema coverage and annotations present, the description supplies the essential missing context: that it modifies the model and does not touch existing object values. Gaps are minor – required-key uniqueness behaviour and the idempotent-on-existing-key semantics are not described.

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 all ten parameters are documented in the schema – including the non-obvious scope_id admin/customer-scope rule. The description adds nothing parameter-specific, so the baseline of 3 applies.

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 ('Ein neues Property-Set anlegen') and parenthetically defines what a property set is ('Gruppe von Feldern fuer Objekttypen'), so an agent knows the object model entity being created. It also implicitly distinguishes itself from per-field assignment, though it never names the sibling tools (onto_property_set_update, onto_object_set_property).

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?

'Nutze es, um wiederkehrende Feldbuendel einmal zu definieren statt Felder einzeln zuzuweisen' gives a concrete when-to-use condition and contrasts it with the per-field pattern, which routes the agent away from onto_object_set_property. No explicit exclusions or prerequisites are stated, and no alternative tool is named.

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