email_security

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

No annotations are present, so the description carries the full burden. It discloses the A-F output, the five protocols checked, and the non-obvious DKIM selector fallback behavior. It does not explain grading methodology or data sources, but for a read-only grader this is reasonably transparent.

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 with no wasted words. The main purpose and output are front-loaded, and the second sentence adds the key parameter nuance about DKIM selectors.

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 two-parameter tool with no output schema, the description covers purpose, output, standards checked, and the one non-obvious parameter. Minor gaps remain around domain format and return structure, but nothing essential is missing.

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 explicitly explains dkim_selectors: common selectors are tried unless the caller passes their own. The domain parameter is self-evident from the surrounding text, though no format caveat is given.

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 opens with a specific verb ('Grade (A-F)') and a specific resource (a domain's email spoofing protection), then enumerates the exact standards checked. This clearly distinguishes it from sibling lookup/recon tools like dns_lookup or domain_whois.

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 intended use is implied clearly: use it when you need an email-security grade for a domain. However, it does not explicitly name alternatives or state when not to use it, leaving some routing judgment to the agent.

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