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

Annotations already cover readOnly, idempotent, openWorld and non-destructive, so the description's marginal contribution is the fixed port 443 connection and the specific data it surfaces (trust result, name match, issuer, expiry, chain, TLS version). This is useful scope detail, though it omits failure modes such as unreachable hosts, timeouts, or handshake errors.

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 front-loaded sentence that opens with the mechanism (connect on 443) before the payload list, with no filler. The trailing colon list is dense and slightly run-on, but every listed field earns its place by documenting a return value for a tool with no output schema.

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?

With no output schema, the description carries the return-value burden well by enumerating issuer, expiry, days left, lifetime, chain and TLS version. It is only incomplete on behavioral edge cases (unreachable domains, invalid certs, non-standard ports) and on how it relates to its sibling tool.

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 schema already explains that a URL is accepted and only its host name is used, so the description adds essentially nothing beyond the word 'domain.' Baseline 3 is appropriate when the single parameter is fully documented in the schema.

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 concrete verb ('Connects... reports') and the exact resource (a domain's TLS certificate on port 443), then enumerates the returned facts, so the agent knows precisely what the tool does. However, it never differentiates itself from the sibling check_domain_expiry, leaving the routing decision implicit.

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 subject matter: a reader infers 'use this when you want to inspect a TLS certificate.' There is no statement of when to prefer this over check_domain_expiry, no prerequisite notes, and no exclusions (e.g., non-443 ports or private/internal hosts).

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