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

With no annotations, the description carries the full burden. It discloses what the result contains, but says nothing about live network behavior: timeout/retry handling, behavior on unreachable hosts or self-signed/expired certs, or whether the call is a plain read. For a network-facing lookup tool that is a meaningful gap, though not a fatal one.

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?

Two sentences, purpose front-loaded, zero filler. The field enumeration partially duplicates the output schema, which is mild waste, but it also signals the tool's altitude at a glance.

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?

An output schema exists, so the description needn't document return values, and it otherwise covers scope and intent adequately. The remaining gap is port specification and failure semantics, which matters because there are no annotations to fall back on.

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 0%, so the description must compensate. It implies the 'domain' parameter exists but never explains format (bare domain vs URL/scheme) and never mentions the 'port' parameter or its default of 443 — the one case where an agent could call it wrong.

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 specific verb+resource: 'TLS certificate of a domain', enumerated with the attributes it returns. An agent can tell instantly this is a TLS inspection tool, not DNS or WHOIS. It stops short of differentiating itself from near-siblings like domain_whois, dns_lookup, or http_headers.

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?

'Use for uptime/expiry monitoring or security checks' gives a clear use context. No exclusions or explicit alternative-routing (e.g. 'use domain_whois for registration data') are provided, so it lands at a solid 4 rather than 5.

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