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

Annotations already declare non-read-only, non-idempotent, non-destructive, closed-world. Beyond that, the description discloses a genuine behavioral trait the annotations cannot convey: token rotation, where the new refresh_token replaces (invalidates) the old one, plus the returned field set. It does not disclose auth/permission requirements or failure modes, keeping it short of a 5.

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 facts are front-loaded, but the text carries redundancy: '(Rotation)' appears twice and the trailing '| EN: refresh, access, token' is keyword padding that adds no meaning. The English gloss on the whole body is absent, leaving a mixed-language definition that is efficient but not tight.

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?

There is no output schema, and the description compensates by naming the return fields {access_token, refresh_token, expires_in}. Combined with the rotation semantics and expiry guidance, an agent has enough to call it correctly; only error/failure behavior is left implicit.

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%, and the sole parameter's description already states the token's origin. The description adds the same sourcing context (login call or a prior refresh) but no syntax, format, or length guidance beyond the schema, so baseline 3 is 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?

States a specific verb and resource ('Token-Selbst-Erneuerung (OAuth2-Refresh)') and precisely what it exchanges: a valid refresh_token for a new access_token plus a rotated refresh_token. The 'OHNE Passwort' qualifier further distinguishes it from the sibling login tool without opening either 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 a clear usage condition — refresh proactively before expiry, with the concrete expiry value (expires_in=10h) — and contrasts implicitly with login via 'ohne Passwort'. It does not name login or auth_status as explicit alternatives, so it falls short of a full when-to-use/when-not routing statement.

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