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

Annotations already declare readOnlyHint=true, so the safe-read profile is covered. The description adds the underlying REST mapping (GET /certificates/{id}), which is minor context, but says nothing about auth requirements, rate limits, or not-found behavior.

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 with no waste, leading with the action and following with the concrete HTTP endpoint. Every element 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?

For a simple read-only single-resource tool with full schema coverage and readOnlyHint annotations, the definition is nearly sufficient. It lacks any hint of what a certificate object contains, though with no output schema that is a minor gap.

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% and the single 'id' parameter is fully documented in the schema, so the baseline is 3. The description's 'by id' adds no syntax or constraint detail beyond what the schema already provides.

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 clear verb and, via the endpoint, the resource ('GET /certificates/{id}'), so an agent can tell this fetches one certificate. However, the body text says only 'a single resource by id' rather than naming the certificate resource directly, and it does not explicitly contrast with the sibling hetzner_list_certificates.

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?

No guidance on when to use this versus the sibling hetzner_list_certificates or the other get_* tools. The 'by id' phrasing weakly implies single-item lookup, but no conditions or alternatives are stated.

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