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 that results include size and server attachment, which is useful, but it says nothing about pagination behavior or result-set size. With the annotation carrying the core behavioral signal, 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?

Two tight sentences with the resource and returned fields front-loaded. The trailing API endpoint mapping ('GET /volumes') is minor but earns its place by grounding the agent in the underlying REST resource.

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 partially compensates by naming the salient return fields (size, attachment). Combined with a fully documented parameter schema and a readOnly annotation, this is nearly complete, though pagination and total-count behavior remain unstated.

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 four parameters (name, page, per_page, label_selector) are fully documented in the schema. The description adds no parameter-level syntax or semantics beyond what the schema provides, so the baseline of 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 ('List block-storage volumes') and even summarizes the returned fields (size, attached server), so the agent knows exactly what the tool yields. It does not explicitly distinguish itself from the sibling 'hetzner_get_volumes', but the list-vs-get distinction is clear from the name and body.

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 'List': enumerate all volumes, optionally narrowed by the schema's name/label filters. There is no explicit when-to-use guidance, no statement of when to prefer this over hetzner_get_volumes, and no mention of prerequisites or pagination expectations.

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