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

Annotations already declare readOnlyHint=false and destructiveHint=false; the description adds genuinely non-obvious context — the credentials are public, shared by all readers, and grant no real protection. Token lifetime, expiry, and failure behavior are not disclosed, keeping it below 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 behavioral facts (token return, credential source, security caveat) are front-loaded and each clause earns its place. The trailing English gloss duplicates the German sentence rather than adding information, costing a point.

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?

An output schema exists, so return values need no explanation, and the description covers the auth source, the purpose, and the security caveat. Missing only edge details — what a failed login looks like and whether the token persists across calls — for full completeness on a login tool.

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 0% (both username and password are bare strings with no descriptions), so the description must carry the load. It partially compensates by pointing to the published credentials page, but gives no format, case, or value hints for either parameter.

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 ('Meldet sich am Demo-Server an') plus the return value ('gibt einen Token zurück') and its consumer role (the two protected tools). It stops short of naming those two tools, so an agent must infer from the sibling list which ones need the token.

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?

Tells the agent where the credentials come from (was-ist-mcp.ch/mcp-ausprobieren) and clarifies that the login protects nothing and only demonstrates an approval step, which is effectively a 'don't over-estimate this' caveat. It never states explicitly that this must be called before the protected tools, leaving that sequencing to inference.

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