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

With no annotations, the description carries full responsibility for behavioral disclosure. It conveys that the tool performs a read-like check, but says nothing about network dependence, response format, error behavior, or what happens with invalid/missing host. The description does not contradict annotations because no annotations are present.

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 short and puts the key verb and resource up front. The leading 'Cert Expiry:' prefix is redundant with the tool name, but the overall length is appropriate and free of filler.

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?

Three optional parameters, no annotations, and no output schema mean the description must do more work. It fails to specify which parameter selects the target certificate, whether the host parameter must include a scheme, or what the response looks like. The tool is simple, but the missing invocation details are material.

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%, which sets a baseline of 3 even though the prose does not explain parameter usage. However, the three schema descriptions are generic placeholders ('Host to process', 'Input to process', 'Domain to process') and the tool description does nothing to clarify whether an agent should pass host, domain, input, or both.

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 names a specific operation ('Check SSL certificate expiry date') and resource, which makes the tool's purpose clear. It does not differentiate it from siblings like x402-ssl-check or x402-domain-expiry, so it misses the top score.

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 usage context is provided: there is no guidance on when to use this tool versus related tools, no mention of required prerequisites, and no indication of what input an agent should supply. The description merely states the core action.

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