mailX tools

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

Annotations provide readOnlyHint=false, destructiveHint=false, idempotentHint=true, and openWorldHint=true, indicating it's a non-destructive, idempotent creation tool. The description adds value by specifying the output format ('record name, value, and type ready to be added to DNS'), which clarifies the tool's behavior beyond annotations. However, it doesn't mention potential rate limits, authentication needs, or error handling.

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 a single, well-structured sentence that efficiently states the action, resource, and output without redundancy. It's front-loaded with the core purpose and avoids unnecessary details, making it highly concise and easy to parse.

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 is reasonably complete: it covers the purpose, output format, and distinguishes from siblings. However, it lacks details on error cases, dependencies (e.g., DNS configuration), or example usage, which could enhance completeness for an agent.

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 description coverage is 100%, with clear descriptions for all parameters (domain_name, email, dmarc_policy) including an enum for dmarc_policy. The description doesn't add any parameter-specific details beyond the schema, such as format examples or constraints, so it meets the baseline of 3 where the schema does the heavy lifting.

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 a DMARC DNS record') and resource ('for a domain'), distinguishing it from sibling tools like dmarc_check (which verifies) and spf_generate (which generates SPF records). It also specifies the output format ('record name, value, and type'), making the purpose explicit and differentiated.

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 implies usage when a DMARC record needs to be created, but it doesn't explicitly state when to use this tool versus alternatives like dmarc_check for verification or spf_generate for SPF records. No guidance is provided on prerequisites, such as DNS access or domain ownership, leaving usage context partially implied.

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