Set up a new sender domain and receive the DNS records required for verification at your provider.
Create a sender domain (POST /domains). The response includes DNS records you must add at your DNS provider before verifying.
| Name | Required | Description | Default |
|---|---|---|---|
| name | Yes | The domain name, e.g. "yourdomain.com". | |
| region | No | Optional sending region. |
Changes observed during successful MCP inspections.
v1.0.2Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the behavioral disclosure burden. It usefully discloses that the response contains DNS records and that verification depends on adding them at the DNS provider, setting accurate expectations for post-creation state. It does not cover all edge cases, but it discloses the most important behavior.
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, each earning its place: the first states the action and endpoint, the second communicates the essential DNS follow-up. It is front-loaded and contains no filler.
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 two-parameter creation tool, the description covers the main workflow: create, receive DNS records, add them, verify. It could name the sibling verify_domain tool explicitly, but the information given is sufficient for the agent to invoke the tool correctly and understand the immediate next step.
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%, so the schema already documents both 'name' and 'region'. The description adds no parameter-specific detail, but none is needed beyond the schema, so the baseline of 3 is appropriate.
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 states a specific action ('Create a sender domain') and the exact endpoint ('POST /domains'), making the tool's purpose immediately clear. The phrase 'before verifying' also distinguishes this tool from the sibling verify_domain operation.
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 gives clear usage context: create the domain, then add the provided DNS records before verifying. It does not explicitly name alternatives or exclusions, but the sequencing is clear enough to guide an agent toward correct use.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.