verify_email

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

Discloses cost (1 Fox Credit per uncached email) and checks performed, but no annotations exist. Missing details on rate limits, error handling, or 'uncached' definition.

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, front-loaded with purpose, then details and cost. No wasted 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, so description should clarify return values. Mentions quality score but incomplete (e.g., no mention of success/failure response, additional fields). Adequate but not fully comprehensive.

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 covers 100% with descriptions for both parameters. Description adds marginal value (cost note) but doesn't elaborate on parameter behavior beyond schema.

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 the tool verifies email deliverability and lists specific checks (syntax, MX, SMTP, etc.) and returns a quality score. It distinguishes from siblings like 'verify_emails' by specifying 'ONE 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?

Usage is implied (verify a single email), but no guidance on when to use this vs 'verify_emails' or 'find_email', and no exclusions or prerequisites mentioned.

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