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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description adds substantial behavior beyond that: counting is limited to outgoing mail, data is refreshed only once per day, the response carries a timestamp, and an unreadable mail log at report time yields an explicit statement with no numbers rather than a misleading zero. That last point directly prevents a common misreading of the result.

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 purpose is front-loaded in the first clause, and the remaining sentences each carry a distinct caveat (outgoing-only counting, report staleness, failure mode, queue independence). It is somewhat dense and long for a one-parameter read tool, but no sentence is filler.

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 response burden and does so: it names the metrics (sent/bounced/deferred today), notes the timestamp field, and explains the failure response explicitly. Combined with the single documented parameter, an agent has everything needed to call it and interpret the result.

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 and schema description coverage is 100%, so the schema already documents 'domain' with an example. The description adds no further syntax, format, or constraint detail for the parameter, so the baseline 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 ('E-Mail-Versandstatus einer Domain abrufen') and immediately narrows scope to sent/bounced/deferred today. The clarification that only outgoing mail for that domain is counted distinguishes it from sibling listing tools like get_email_accounts or get_spam_filter without the agent needing to open another 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 clear context for when the data is meaningful: it comes from the once-daily turbocheck report, so events since the last run are absent, and stuck mails come from a separate queue. It does not explicitly name alternative tools (e.g. get_email_accounts) or state when not to use this one, so it stops short of full when/when-not guidance.

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