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

Annotations already supply readOnlyHint=true and openWorldHint=true, reducing the need for safety disclosures. The description adds value by specifying the return payload (issuer, expiry, validity), but it does not detail potential errors, timeouts, or exact output formatting. This is a moderate amount of extra transparency beyond the annotations.

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 exceptionally concise: two sentences plus an args line, with the purpose front-loaded. No filler or redundant phrases exist; each word contributes meaning.

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 simple single-parameter read-only tool, the description covers the core function and return fields. It omits edge cases like invalid domains or certificate errors, but these are not critical given the annotations and lack of an output schema. Adequate for an agent to invoke the tool correctly.

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 schema only defines 'domain' as a string with no description (0% coverage). The description compensates by explaining the parameter as 'Domain name' and providing an example ('example.com'), which clarifies the expected format. This is essential for correct usage and goes beyond 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?

The description clearly states the tool checks SSL certificates for a domain and lists the return fields (issuer, expiry, validity). The specific verb 'Check' and resource 'SSL certificate' make the purpose unambiguous, and it is easily distinguished from sibling tools like dns_lookup and whois_lookup.

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 description implies the tool is used when SSL certificate information is needed, but it does not explicitly state when to use this tool over alternatives or mention any exclusions. No comparison to sibling tools is provided, so the guidance is only implicit.

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