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

The description adds real behavioral context beyond the annotations: this is an asynchronous operation that returns an action id which must be polled via hetzner_get_action, and it cites the underlying endpoint. It does not address permissions or idempotency, but the async contract is the key disclosure an agent needs.

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?

Three terse sentences that front-load the operation, then the follow-up action, then the API mapping. No filler, every clause earns its place.

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 compensates by explaining the return value (an action id) and how to consume it. Nothing essential is missing for a single-parameter action tool, though permission or state preconditions would make it fully complete.

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 with 100% schema description coverage ('The server to start'), so the schema already carries the semantics. The description adds nothing about the server_id beyond restating that the server is stopped, which is the correct baseline of 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 ('Power on a stopped server') and scopes it to stopped servers, which implicitly separates it from hetzner_reboot_server and hetzner_shutdown_server. It stops short of naming those siblings explicitly, so an agent must infer the boundary from the word 'stopped'.

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?

Usage is implied by the 'stopped server' precondition, and the description helpfully routes the caller to hetzner_get_action for polling, but it never states when to prefer this over reboot or shutdown, nor any preconditions such as server state or permissions.

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