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

The annotations already declare idempotentHint=true, destructiveHint=false, and readOnlyHint=false. The description adds useful behavioral context beyond this by clarifying that the tool triggers a manual SSL request and that issuance is normally automatic, plus a DNS prerequisite. This is valuable but not exhaustive; it doesn't describe possible delays or failure modes, though those may be covered by the output schema.

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?

The description is two sentences with no filler. The core purpose is front-loaded in the first sentence, and the second sentence adds essential timing context. Every word contributes.

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?

Given the tool's low complexity (one well-documented parameter), the rich annotations, and the presence of an output schema, the description fully covers the practical context an agent needs: when to call it, why it exists, and how it relates to automatic issuance.

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 `site` parameter is already well-described with examples and validation guidance. The description adds general context about the website but no additional parameter-level semantics, so the baseline score of 3 is 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?

The description clearly states the action ('asks for a new free SSL certificate') and the resource ('for the website'). It also differentiates this tool from the sibling set by focusing on SSL certificates rather than DNS, files, or database operations, and from automatic certificate issuance.

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 description gives explicit timing: 'Useful right after the domain's DNS starts pointing here.' It also says when the tool is not needed: 'Certificates are otherwise issued and renewed automatically.' This provides both when-to-use and when-not-to-use guidance.

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