x402node_validate_email

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

With no annotations, the description must carry behavioral information. It mentions format validation, MX record checking, and disposable email detection. However, it does not describe the output format, error handling, or rate limits. The pricing note is helpful but incomplete for full transparency.

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 somewhat repetitive with multiple synonyms in a list, and includes a pricing line that may not be essential for tool selection. It could be more concise while retaining key information. It is front-loaded with the core purpose.

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?

There is no output schema, so the description should explain what the tool returns (e.g., boolean, object with details). It does not, leaving a significant gap. Also missing error behavior or performance considerations. The addition of pricing is extra but not core to completeness.

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 coverage is 100%, so baseline is 3. The description reiterates the 'optional MX check' aspect but does not add new semantic details beyond what the schema provides. It offers context but no deeper parameter meaning.

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 it validates email addresses, lists multiple synonyms (format check, RFC 5322, etc.), and explicitly mentions optional MX record checking and disposable email detection. It differentiates from sibling validation tools by focusing solely on email.

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 specifies use cases: 'signup pipelines, lead validation, bot filtering.' This gives context for when to use it. However, it does not explicitly state when not to use it or compare to other sibling validation tools, so some guidance is implicit but not exhaustive.

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