check_mta_sts

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

The description explicitly states it is read-only, mentions that it performs DNS and HTTPS GET requests only, and outlines exactly what it returns (parsed policy, TLS cert validity, consistency warnings). This fully discloses behavior, aligning with readOnlyHint and no side effects. No contradictions noted.

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 plus a final note. It front-loads the tool's purpose and key actions, provides return details, and ends with a pairing recommendation. Every sentence adds value; no fluff or repetition.

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 (one param, no nested objects), the description sufficiently covers inputs, process, and outputs. It also provides context on when to use it (checking MTA-STS for inbound mail) and how to complement with check_smtp_tls. There is no missing essential information for a user to decide to invoke it.

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 only parameter 'domain' already has a detailed description in the schema ('Domain name only, e.g. example.com (no URL, path, or protocol)'), which fully covers its meaning. The tool description repeats part of that (constructs MTA-STS records) but doesn't add new constraints or clarifications. Since schema coverage is 100%, 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 explicitly states what the tool does: checks MTA-STS by reading DNS TXT record and HTTPS policy file, and returns parsed policy, TLS certificate validity, and consistency warnings. It also states the use case:

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?

Provides a clear usage scenario (

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