verify_email

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

Discloses read-only nature, API key requirement, and rate limit (30/min per user) without any annotations. Also describes return value (deliverability score and risk assessment).

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?

Concise, packing core purpose, behavior, guidelines, and return info into a few sentences. No wasted words, well front-loaded.

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?

Covers all essential aspects for a simple tool: purpose, behavior, auth, rate limit, usage context, and return summary. No 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?

Input schema already provides 100% coverage with description for 'email' parameter. Description does not add additional semantic detail beyond the schema, so baseline 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?

Description clearly states 'Check email deliverability in real-time' with specific checks (MX records, SMTP, disposable/role detection). Differentiates from siblings like get_user_stats and search_leads by focusing on email verification.

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?

Explicitly says 'Use after search_leads or before sending campaigns', providing clear context. Lacks explicit exclusions or alternatives, but sufficiently guides usage.

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