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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds the upstream API mapping (GET /servers), which is modestly useful, but it says nothing about pagination behavior even though page/per_page exist, nor about rate limits or the shape of results. With annotations carrying the safety burden, a 3 is appropriate.

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?

A single front-loaded sentence covers scope and filters, followed by a short API reference. Nothing is padded and the essential information comes first, though the trailing API line is near-redundant.

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 list tool with full schema coverage and annotations covering safety, the description supplies adequate context. The main omission is pagination/result-set behavior, which matters for a paged collection endpoint but is not fatal.

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 description coverage is 100%, so all five parameters (name, page, per_page, status, label_selector) are documented in the schema itself. The description restates name/status/label_selector at a high level but adds no syntax or semantics beyond the schema, which is exactly the baseline-3 case.

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 (List) and resource (servers) and scopes it to "the token's project," with the three filter axes named. The plural/collection scope implicitly separates it from the singular hetzner_get_server sibling, but no sibling is named explicitly, so it stops short of a 5.

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 only implied: the description makes clear this is for enumerating servers in the current project with optional filters. It never states when to prefer it over hetzner_get_server for a single server, nor any exclusions or prerequisites, so it lands at minimum-viable guidance.

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