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 useful fact that results include expiry and that both managed and uploaded certificates are returned, plus the underlying API endpoint. It says nothing about pagination, default page size, or result volume, which is the main behavioral gap for a list endpoint that supports paging.

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, zero waste, with the resource and the notable scope (managed or uploaded, expiry) front-loaded before the API endpoint reference. Nothing is padded.

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 0 required params, full schema coverage, and no output schema, this is close to complete. The main omission is pagination behavior, though the page/per_page parameters in the schema partly compensate.

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% with four well-documented parameters (name, page, per_page, label_selector), so the schema carries the burden. The description adds no parameter detail beyond what the schema already states, making the baseline 3 appropriate.

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 (TLS certificates), and adds scope detail that the sibling get_certificates does not: 'managed or uploaded' and 'their expiry'. It does not explicitly differentiate itself from the near-identically named hetzner_get_certificates, which slightly weakens disambiguation.

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 when-to-use guidance and no alternative named. The sibling set contains hetzner_get_certificates, and an agent gets no hint whether that returns one certificate or a filtered set, nor when to prefer this tool. Usage is only implied by the verb 'list'.

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