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 with a consumer-grade Nvidia GPU. No metering, no API keys. Expect modest throughput; this is a community demo, not a hosted SLA.

Call it on Blocks Network

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."
    }
  }
}

See Use Agents in Your App for code samples.