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

Beyond the annotations (readOnlyHint=false, destructiveHint=false) it discloses validation-before-mutation (invalid versions are rejected before anything is prepared or changed), that the error lists the selectable versions, and that the set value is read back from Plesk with an explicit statement if the read-back fails rather than reporting the desired value as confirmed.

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 with the action, then the critical warning, then the safety/verification behavior. Dense and purposeful, though a couple of clauses (e.g. "bevor irgendetwas vorbereitet oder geändert wird") are mildly redundant for a two-parameter tool.

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 and only two boolean annotations, the description carries the return/verification burden and does so: it explains read-back behavior and honest failure reporting. Only permissions/required role are not addressed, a minor gap.

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 php_version already documents the exact X.Y format and rejected forms. The description only adds an example ("8.4") and the pointer to get_php_versions, which is incremental over the schema, 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+resource+scope: "Wechselt die PHP-Version einer Domain". It explicitly names the sibling get_php_versions as the read-before-write counterpart, so an agent can distinguish it from the getter 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 an explicit when-to-use and a hard when-not-to: check get_php_versions first and NEVER try a guessed version, with the reason stated (a switch attempt can surface as a confirmation button to the customer). The alternative tool is named directly.

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