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

Annotations already carry the safety profile (readOnlyHint=true, destructiveHint=false), so the bar is lower. The description still adds real context: data is read live from the hosting system, the returned selectable values ('8.4') map exactly to what switch_php_version accepts, and an unreadable value must not be interpreted as 'none'. Return format/pagination is not covered, keeping it at 4 rather than 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-loaded correctly: what it reads first, then its relation to switch_php_version and the question it answers, then the edge-case warning. Every clause carries operational value despite the dense em-dash style.

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 read-only, single-parameter tool with annotations already covering the safety profile and no output schema, the description supplies everything needed: purpose, sibling routing, value-format contract with switch_php_version, and a failure-mode warning.

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 100% and the single domain parameter is fully documented in the schema (including the 'example.de' example). The only description-level addition is emphasizing the single-domain scope ('für EINE Domain'), which is marginal. Baseline 3 is appropriate when the schema does the heavy lifting.

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+resource with scope ('Liest für EINE Domain die eingestellte PHP-Version und die Versionen, die auf ihrem Server wählbar sind') and explicitly names its sibling counterpart switch_php_version. An agent can distinguish it from switch_php_version and every other get_* tool 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 exact alternative (switch_php_version) and the condition selecting this one, plus the question it answers ('Welche PHP-Versionen gibt es?'). It even gives when-not guidance: if a value is reported unreadable, don't guess and don't trigger a trial switch.

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