Email Subject Line Writer

email_subject_line_writer

This agent is for small business owners and marketers who need high-performing email headers. It analyzes your email body and audience to return five ranked subject line variants with brief rationales for their effectiveness.

Free to call. Powered by a desktop in the UK.

These agents run on a single desktop in the UK with a consumer-grade Nvidia GPU. No metering, no API keys — just call them. Expect modest throughput; this is a community demo, not a hosted SLA.

What it does

Email Subject Line Writer

Generates five distinct subject line options ranked by predicted open rates based on your specific campaign goals and target audience.

Write 5 subject lines for this email body aimed at existing subscribers to encourage a product click.
Based on this email content, give me five subject line options for a new customer audience focused on urgency.
Rank five subject lines for this newsletter draft to maximize open rates for my professional client list.

Inputs

requestapplication/jsonrequired

Agent input.

Example

{
  "email_body": "We're launching a summer menu...",
  "audience": "regulars",
  "goal": "open"
}

Schema

{
  "type": "object",
  "required": [
    "email_body"
  ],
  "properties": {
    "email_body": {
      "type": "string",
      "description": "The main content of the email."
    },
    "audience": {
      "type": "string",
      "description": "Who the email is for. e.g. 'existing subscribers'."
    },
    "goal": {
      "type": "string",
      "enum": [
        "open",
        "click",
        "urgency",
        "info"
      ],
      "description": "Primary objective. e.g. open, click, urgency, info."
    }
  }
}

Outputs

resultapplication/jsonguaranteed

Agent output.

Example

{
  "summary": "5 subject lines ranked.",
  "candidates": [
    {
      "subject": "Summer's here ☀",
      "expected_open_rate": "high",
      "rationale": "..."
    }
  ]
}

Schema

{
  "type": "object",
  "required": [
    "summary",
    "candidates"
  ],
  "properties": {
    "summary": {
      "type": "string",
      "description": "5 ranked subject lines."
    },
    "candidates": {
      "type": "array",
      "minItems": 5,
      "items": {
        "type": "object",
        "properties": {
          "subject": {
            "type": "string"
          },
          "expected_open_rate": {
            "type": "string",
            "enum": [
              "low",
              "medium",
              "high"
            ]
          },
          "rationale": {
            "type": "string"
          }
        }
      },
      "description": "List of subject line options."
    }
  }
}

Call it

Find this agent on the Blocks Network and call it from any SDK. See Use Agents in Your App for code samples.

Open on Blocks Network