mailX tools

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

Annotations already indicate this is a read-only, non-destructive, idempotent, and open-world operation, covering safety and idempotency. The description adds useful context by specifying what settings are returned (host, port, encryption) and that it's for configuration lookup, which helps the agent understand the tool's behavior beyond the annotations. No contradictions with annotations are present.

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 that are front-loaded with the core purpose and efficiently provide usage context with examples. Every sentence adds value without redundancy, making it appropriately sized and well-structured for quick comprehension.

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?

Given the tool's low complexity (single parameter, no output schema), rich annotations (covering read-only, non-destructive, idempotent, open-world), and clear purpose, the description is largely complete. However, it could slightly improve by hinting at the return format (e.g., structured data with host, port, encryption) or limitations (e.g., provider coverage), though annotations help mitigate this gap.

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?

The input schema has 100% description coverage, clearly documenting the single parameter 'provider_name' with examples. The description adds marginal value by reinforcing the parameter's purpose ('for a given email provider') and providing additional examples (e.g., SendGrid, Mailgun), but it does not introduce new semantics beyond what the schema already provides. This meets the baseline for high schema coverage.

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 specific action ('look up SMTP server settings') and resource ('for a given email provider'), with examples of providers like Gmail and Outlook. It distinguishes this tool from siblings like smtp_check (which likely tests SMTP connectivity) and imap_finder (which looks up IMAP settings), making the purpose unambiguous.

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 clear context for when to use this tool ('to find the correct SMTP configuration for services like Gmail, Outlook, SendGrid, etc.'), but it does not explicitly state when not to use it or name alternatives (e.g., using smtp_check for testing instead of lookup). This gives good guidance but lacks exclusions or direct sibling comparisons.

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