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

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=false, and the description usefully adds what the mutation actually touches: only the read status, not the content, and nothing is deleted. 'Die Meldung selbst bleibt abrufbar' reassures the agent the record survives, though it says nothing about permissions or error behavior.

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 German sentences are front-loaded and carry real information, but the trailing '| EN: end user, customer, portal, notification, map, scope' is keyword-stuffing that adds no operational meaning, and the mixed-language framing costs some clarity.

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 one-parameter state-change tool with full annotation coverage and no output schema, the description covers purpose, the scope of the mutation, id provenance, and post-state retrievability. Only permission requirements and the response shape are left implicit, which is acceptable at this complexity.

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?

There is a single parameter with 100% schema description coverage, and the schema already says it is the notification id from ontouser_notification_index. The description restates the same origin for the id but adds no new meaning about format, validity, or failure on unknown ids, 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 ('Eine Benachrichtigung als gelesen markieren'), which is unambiguous and clearly distinct from the read-only sibling ontouser_notification_index and from ontouser_notification_send. An agent knows exactly what state change is being requested.

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 nach ontouser_notification_index' gives an explicit sequencing hint and names the sibling that supplies the id. What is missing is any exclusion guidance (e.g. when not to mark as read, or how it relates to get_notifications), so it stops short of full when/when-not coverage.

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