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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safe-read, external-network profile is covered. The description adds useful behavioral content beyond that by naming what the inspection surfaces — issuer, expiry, protocol, and expiring/self-signed/mismatched flags — which tells the agent this is a passive diagnostic that reports problems rather than fixing them.

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?

One sentence, front-loaded with the action and resource, then the returned fields. Nothing is padded or restated from the title or annotations.

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?

No output schema exists, so the description carrying the result fields (issuer, expiry, protocol, flags) is exactly what an agent needs to interpret the response. Minor gaps remain — no mention of behavior for unreachable/non-HTTPS domains or of output format — but for a one-parameter read-only check it is sufficiently complete.

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?

Single parameter with 100% schema description coverage ('Domain, e.g. example.com'), so the schema does the work. The description adds no extra meaning such as whether a scheme, port, or hostname-only form is acceptable, which is the baseline-3 case when coverage is high.

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?

Specific verb (Inspect) plus a precise resource (a domain's SSL/TLS certificate), and it enumerates the concrete outputs (issuer, expiry, protocol, expiry/self-signed/mismatch flags). The resource is cleanly distinct from every sibling (email security, headers, SEO, AI visibility, local code), so an agent can route to it without opening a schema.

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?

Usage is only implied by the purpose: an agent infers 'use this when you need certificate health for a domain.' There is no explicit when-to-use statement, no mention of prerequisites (public reachability of the domain), and no reference to alternatives such as check_security_headers for adjacent checks.

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