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

Annotations already declare readOnlyHint=true, so the safety profile is known. The description does add the useful clarification that results include snapshots and backups, not just system images, but 'Hetzner Cloud: GET /images.' is just an endpoint mapping and conveys no extra behavior such as pagination defaults or filtering semantics.

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 sentences, front-loaded with the resource and its purpose. The trailing 'Hetzner Cloud: GET /images.' earns marginal value as an API reference but is not the leading information an agent needs.

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 6 optional filters, a 100%-covered schema, and no output schema, the description is sufficient to know what is returned and what can be filtered. It could mention that results are paginated, but nothing critical is missing.

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 six filters (name, type, architecture, label_selector, page, per_page) are already documented in the schema. The description adds no syntax, defaults, or filter-combination guidance beyond that, 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 ('List') plus resource ('OS images, snapshots and backups') and the scope of what they're for ('you can boot or restore from'). It is clearly distinct from the mutating siblings like hetzner_create_image_from_server, though it never names a sibling to route against.

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?

The phrase 'you can boot or restore from' hints at the scenario (finding an image to provision a server), but there are no explicit when-to-use, when-not-to-use, or alternative conditions given. Usage is implied rather than stated.

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