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

readOnlyHint=true already establishes this is a safe read with no side effects. Beyond that the description adds real context: the response is the FULL price list (not a filtered subset) and is scoped to the project's currency, plus the underlying endpoint. It omits any note on rate limits or the fact that pricing returns per-location detail.

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?

One front-loaded sentence stating what is fetched and what it contains, followed by a short API endpoint reference for agents that reason in HTTP terms. No filler, no repetition of the title.

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 input or output schema, the description carries the burden of describing the return payload, and enumerating the covered resource categories does that reasonably well. It stops short of indicating the price shape (hourly vs monthly, per-location breakdown), which an agent reading only this text would still have to discover from the response.

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?

The tool takes zero parameters, so the 4 baseline applies. The description still adds value by noting the currency dimension is determined by the project rather than passed in, which preempts an agent from looking for a currency argument.

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?

Specific verb ('Fetch') plus resource ('full price list') with an explicit enumeration of what the list covers: server types, volumes, traffic, floating IPs, load balancers and backups. No sibling tool does pricing, so the agent can distinguish it immediately from the many hetzner_get_*/list_* inventory tools.

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 (call when you need to compute or display costs) and the description usefully scopes it to the project's currency, but it never states when to reach for this versus the location/type listing tools or whether extra inputs are needed. With no competing pricing sibling there is little routing to do, so this is adequate rather than explicit.

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