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

readOnlyHint=true already establishes this is a safe read. The description adds that both managed and uploaded certificates are returned and that expiry is included, which is modest but genuine value beyond the annotations. It says nothing about pagination behavior or result limits, which the schema's page/per_page params imply exist.

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, the substantive scope statement first and the API mapping second. No filler and nothing buried.

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 annotation-carried safety, the description covers what is returned (cert types, expiry). The only real omission is disambiguating from hetzner_get_certificates, and pagination behavior is left implicit.

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 name, page, per_page, and label_selector are already fully documented in the schema. The description adds no parameter-level meaning, so the baseline 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 TLS certificates') and adds scope ('managed or uploaded, and their expiry'), which tells the agent what the results contain. It does not, however, distinguish itself from the closely named sibling hetzner_get_certificates, leaving an ambiguity the agent must resolve on its own.

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?

There is no when-to-use guidance, no exclusions, and no routing to an alternative. With hetzner_get_certificates sitting in the sibling list, the absence of any 'use this to enumerate, use get_certificates to fetch one' distinction is a real gap.

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