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

Annotations already mark the operation as read-only and non-destructive, so the description earns credit for adding measurement-source context: Korean network, CT-log fallback, global PoP vs. Korea verification, and chain ordering. It does not cover rate limits or failure behavior, but it discloses far more than the annotations alone.

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 main action is front-loaded and the colon-separated list packs many distinct checks into one sentence without filler. It is dense and slightly run-on, but every clause contributes information, so it remains efficient.

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 single-parameter diagnostic tool with no output schema, the enumerated checks effectively tell the agent what results to expect. It does not describe result formatting, ordering, or edge cases like invalid domains, but the annotation set and simple schema keep the remaining gap small.

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?

The input schema already documents the only parameter, domain, with an example, and the description adds no syntax, formatting, or validation details beyond that. With 100% schema coverage, the baseline 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 opens with a specific verb and resource ('Check one domain's TLS certificate in depth') and then enumerates distinct checks such as expiry, CT deployment gaps, live verification, chain, revocation, SAN, and CA incidents. This makes the tool easy to distinguish from siblings like check_expiry or check_dns even without explicit comparisons.

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 detailed scope implies the tool is for deep certificate diagnostics rather than simple expiry checks, but the description never states when to prefer it over siblings such as check_expiry or check_security. There is no explicit when-to-use/when-not-to-use guidance, leaving the agent to infer usage from the feature list.

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