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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered, but the description adds real operational context: data is live from Plesk, an absent forwarding is an affirmative 'none configured' answer rather than missing data, and forwarding targets are emitted verbatim even for foreign domains. It doesn't discuss pagination or freshness/rate limits, 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?

Front-loads the verb and returned fields, then layers semantic caveats. Mildly verbose — the aside about what chat previously couldn't show is historical justification rather than actionable instruction — but each sentence still carries usable meaning.

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?

With no output schema, the description carries the return-value burden and does so by listing the exact fields returned plus how empty forwarding/alias values should be interpreted. Nothing essential for correct invocation is missing for a one-parameter read 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?

Single required 'domain' parameter with 100% schema description coverage ('Die Domain, z. B. example.com'), so the schema already carries the meaning. The description adds no format or scoping detail beyond what the schema states, which is the baseline 3.

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 ('E-Mail-Konten einer Domain auflisten') and enumerates the returned fields (Adresse, Speicherkontingent, Weiterleitung, Aliase). It explicitly positions itself against siblings set_email_forwarding and set_email_alias as their read counterpart, so an agent can distinguish it without opening a 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?

Names the write siblings it complements and describes the gap it closes ('wohin die Post eines Postfachs geht'). This gives clear context for when to reach for it, though it stops short of explicit when-not-to-use conditions or comparison with other read tools like get_email_status.

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