mailX tools

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

The description adds valuable behavioral context beyond annotations: it specifies the return format ('Returns the record name, value, and type ready to be added to DNS'), which is crucial since there's no output schema. Annotations already cover idempotency and non-destructive nature, but the description usefully explains what the tool produces. No contradiction with annotations.

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 perfectly concise with two sentences that each earn their place: the first states the purpose and context, the second specifies the return format. It's front-loaded with the core functionality and wastes no words. The structure is logical and efficient.

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 moderate complexity (3 parameters, no output schema), the description provides good contextual completeness. It explains what the tool does and what it returns, which is essential since there's no output schema. However, it could be more complete by mentioning typical use cases or prerequisites (like needing domain ownership). The annotations cover safety aspects well.

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?

With 100% schema description coverage, the input schema already fully documents all three parameters. The description doesn't add any additional parameter semantics beyond what's in the schema descriptions. It mentions the provider parameter generically but doesn't elaborate on the specific provider identifiers or their effects beyond what the schema already states.

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 ('Generate an SPF DNS record'), target resource ('for a domain'), and purpose ('based on the email provider being used'). It distinguishes from sibling tools like spf_check (which verifies rather than generates) and dmarc_generate (which generates a different type of DNS record).

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 about when to use this tool ('Generate an SPF DNS record for a domain based on the email provider being used'), but doesn't explicitly state when not to use it or name specific alternatives. It implies usage for SPF record generation rather than verification (spf_check) or other DNS tools, but lacks explicit exclusions or comparisons.

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