check_mta_sts

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

Despite no annotations, the description fully discloses the behavior: it is read-only, performs only DNS and HTTPS GET requests, and details the specific checks (TXT record, policy file, certificate validity, consistency). No side effects or mutations are implied.

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 concise (two sentences) and well-structured: first sentence states purpose and method, second sentence describes return values and usage guidance. Every sentence adds value without redundancy.

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?

Given the tool's simplicity (single parameter, no output schema, no annotations), the description adequately covers what the tool does, what it returns, and how to use it. It even describes the return values in detail, compensating for the lack of output schema.

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 has 100% coverage with a clear description for the 'domain' parameter (type string, example). The description does not add additional meaning or constraints beyond the schema, so a baseline score 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 clearly states the tool performs a read-only check of MTA-STS by querying DNS TXT record and HTTPS policy file. It specifies the exact resources and distinguishes itself from sibling tools like check_smtp_tls by suggesting pairing for live validation.

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 explicitly states the purpose: to verify enforced TLS for inbound mail, and recommends pairing with check_smtp_tls for live STARTTLS validation. It also notes that no authentication is needed, but lacks explicit 'when not to use' guidance.

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