add_domainRegisters a sending domain and returns the DNS records to create before verification. Use it to set up a new domain for transactional email sending.
Add a sending domain. The response lists the DNS records to create before calling verify_domain.
| Name | Required | Description | Default |
|---|---|---|---|
| domain_name | Yes | Such as acme.com or mail.acme.com. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the safety profile (write, non-idempotent, non-destructive, closed-world), and the description adds genuinely new behavioral context: the response carries the DNS records to create and a verification step is required afterward. It omits failure behavior for duplicate domains or invalid input, so it stops short of full disclosure.
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 short sentences, front-loaded with the action and followed by the one piece of information an agent could not infer. Nothing is redundant.
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?
For a one-parameter creation tool with annotations and no output schema, the description covers the essential gap: what comes back and what to do next. A note on duplicate-domain behavior would make it fully complete.
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?
There is a single parameter with 100% schema description coverage including an example format, so the schema already does the work. The description adds no further meaning about expected domain format, baseline 3 applies.
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 opens with a specific verb+resource ('Add a sending domain'), which is unambiguous against siblings like list_domains, get_domain, and verify_domain. It does not explicitly say which sibling to use instead, but the operation is distinct enough that confusion is unlikely.
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?
It supplies real workflow context: the caller must create the returned DNS records before calling verify_domain, which tells the agent where this step fits. There are no explicit when-not conditions, for example what to do if the domain already exists.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.