Update an existing email alias by replacing its destination addresses with a new list. The change is accepted and processed in the background.
Replace the destination addresses of an existing alias. The change is processed in the background (202 Accepted).
| Name | Required | Description | Default |
|---|---|---|---|
| domain_name | Yes | ||
| destinations | Yes | The full new list of destination addresses | |
| email_address | Yes | The alias address |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already communicate non-read-only, idempotent, and non-destructive behavior. The description adds valuable behavioral context by noting that the change is processed asynchronously and returns 202 Accepted. This goes beyond the structured 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 a single, front-loaded sentence that states the core action and the key asynchronous behavior. Every word earns its place; there is no repetition or 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 simple three-parameter tool with no output schema, the definition is nearly complete: required parameters are clear, the mutation behavior is stated, and the async 202 response is disclosed. The main gaps are the undocumented domain_name parameter and no mention of how to check completion, but these are minor given the tool's simplicity.
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 schema describes destinations as 'The full new list of destination addresses' and email_address as 'The alias address,' which covers two of three parameters. The description reinforces these meanings but adds no semantic detail for the undocumented domain_name parameter, leaving a moderate gap.
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 uses a specific verb and resource: 'Replace the destination addresses of an existing alias.' This clearly distinguishes the tool from sibling tools like combell_mail_zones_aliases_create and combell_mail_zones_aliases_delete.
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 this tool is for updating an existing alias's destinations rather than creating or deleting alias records, but it does not explicitly name alternatives or state when not to use it. The context is clear enough to infer, but no direct routing guidance is provided.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.