Send marketing emails to customers or prospects using campaign templates or custom content. Choose template ID or provide custom body for personalized outreach.
Send a marketing email to a customer or prospect. Can use a campaign template or custom body content.
| Name | Required | Description | Default |
|---|---|---|---|
| to | Yes | Recipient email address | |
| template_id | No | Campaign template ID to use | |
| custom_body | No | Custom email body (overrides template) |
Changes observed during successful MCP inspections.
v2.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, leaving the description to carry the full burden of behavioral disclosure. The description only mentions the two content modes, but fails to disclose side effects (e.g., email actually sent), permission requirements, or response/error behavior. For a mutation-like tool, this is a significant transparency gap.
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 two sentences, front-loaded with the core purpose, and contains no fluff. Each clause adds relevant information, making it highly concise and well-structured.
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?
With 3 parameters, no output schema, and no annotations, the description provides the essential purpose and a hint of parameter relationships, but does not explain return values, side effects, or prerequisites. It is minimally viable but leaves gaps for an agent that needs to know the impact and success criteria.
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 coverage is 100%, so the baseline is 3. The description's mention of 'campaign template or custom body content' adds no new meaning beyond the schema, which already documents that custom_body overrides template. The description does not enhance parameter understanding.
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 starts with a specific verb and resource: 'Send a marketing email to a customer or prospect.' It also notes the two content modes (campaign template or custom body), making the tool's scope clear and distinct from siblings like mktg.manage_campaigns.
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 when to use: to send a marketing email to a customer or prospect, with the option of a template or custom content. However, it does not explicitly exclude alternatives or mention when not to use it, so it lacks full exclusion guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.