Check a domain mail configuration

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

Annotations already declare readOnlyHint and openWorldHint, establishing a safe read operation. The description adds valuable behavioral context: grading (A-F), fixes for problems, default summary vs. section drill-down, and the domain-not-email constraint. No contradiction with 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?

Three sentences, front-loaded with the primary function, followed by use cases and input/behavior details. No wasted words; each sentence earns its place.

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?

The tool is complex (multiple sections, grading, fixes), but the description covers scope, output style (grades, fixes), and navigation (section parameter). With no output schema, it doesn't spell out return format in detail, but it still conveys sufficient behavior for a read-only domain audit.

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 already covers all three parameters with descriptions (100% coverage). The description goes beyond the schema by clarifying that 'domain' must be a domain, not an email address, and explaining how 'section' changes output (summary vs. full records). This adds meaningful semantic contrast.

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 uses the specific verb 'Audit' and resource 'a domain's email setup', enumerating concrete checks (MX, SPF, DKIM, DMARC, etc.). It clearly distinguishes itself from siblings like validate_email and check_spf by covering the entire domain setup rather than a single email or SPF record.

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 explicit use cases ('can this domain send and receive mail', 'why do our messages land in spam') and an exclusion ('takes a domain, not an email address'). While it doesn't name alternative sibling tools, the intended context is clear.

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