email_auth

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

With no annotations, the description carries full burden. It discloses that the tool checks SPF, DMARC, DKIM, and gives a verdict, plus rate limits and env variable for higher tier. Missing details on response format or error handling, but core behavior is clear and adds context.

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 two sentences: first sentence states the functionality, second sentence provides rate limit and environment variable info. It is front-loaded, concise, and contains no unnecessary words.

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?

No output schema exists, so the description should explain return values. It mentions 'spoofability verdict' but not its format or contents. Additionally, error cases (e.g., invalid domain) are not addressed. For a simple tool, it's partially complete but leaves gaps.

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 has one param (domain) with description 'The domain to analyze' (100% coverage). The description adds meaning by specifying which authentication records are checked (SPF, DMARC, DKIM) and the spoofability verdict, going beyond the schema's generic description.

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 the tool audits email authentication (SPF, DMARC, DKIM with common selectors) and provides a spoofability verdict. It clearly distinguishes from siblings like verify_email or dns_lookup by specifying the unique function.

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 provides rate limit info but lacks explicit guidance on when to use this tool versus sibling tools (e.g., verify_email, dns_lookup). No exclusions or use-cases are stated beyond the basic audit function.

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