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

Annotations already flag destructiveHint=true, so the safety profile is covered. The description adds genuinely useful context by disclosing that the reboot is graceful and performed via ACPI, but it omits operational behavior such as service downtime, whether the call is asynchronous and returns an action, or how long the server stays unavailable.

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?

Two short, front-loaded sentences with no filler. The trailing REST endpoint reference is semi-redundant but cheap and aids API-aware callers.

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 one-parameter action this is nearly adequate, but with no output schema the description should note that this is an asynchronous action whose result must be polled (via hetzner_get_action), and it should note the server-state prerequisite. Those gaps keep it at minimum-viable.

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?

Only one parameter exists and schema description coverage is 100%, so the schema already documents server_id as the target. The description adds no syntax, format, or constraint detail beyond what the schema provides; 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 ('Reboot a server') and adds the mechanism ('gracefully via ACPI'), which distinguishes it from a hard reset. It does not explicitly contrast with siblings like hetzner_shutdown_server or hetzner_poweron_server, but the verb itself is unambiguous.

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?

There is no guidance on when to use reboot versus the sibling shutdown_server or poweron_server, nor any prerequisites or state requirements (e.g., server must be running). The 'gracefully via ACPI' phrase hints at graceful-vs-hard semantics but never states when each is appropriate.

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