Test Loyalty Reward Subject Lines in Continue
Loyalty reward emails only earn opens if the subject line signals real value. With marginal's email MCP server connected to Continue, you can draft, test, and measure loyalty reward subject lines without leaving your editor's AI chat.
Why pair Continue with loyalty reward campaigns
Continue gives you an AI agent inside your editor that can call external tools. Point it at marginal and that agent gains the ability to run a real subject line A/B test against your loyalty reward audience — generating phrasing options, launching the send, and reporting which variant wins.
Loyalty rewards are a high-stakes use case: subscribers already trust you, so the subject line decides whether a points balance, tier upgrade, or birthday gift gets noticed. Iterating fast on copy directly inside Continue keeps the loop tight.
- Brainstorm reward-focused angles (points expiring, exclusive perk, VIP status) in chat
- Launch the subject line test as a managed send through marginal
- Pull open and click metrics back into Continue to decide the next move
The marginal tools behind the workflow
Once marginal is connected as an MCP server, Continue can invoke four tools that map cleanly to a loyalty reward subject line test.
- generate_variants — produce multiple loyalty reward subject lines from a single prompt
- launch_test — start a subject line A/B test with a managed send and tracking
- get_results — read open/click tracking and within-test lift metrics
- recommend_next — let the AI agent suggest the next variant or winner to roll out
A sample loyalty reward test flow
Ask Continue to draft variants framed around your reward, then hand them to marginal to test. A typical conversation moves from idea to measured result in a few turns.
Because marginal is hosted at https://marginal.sh/mcp, there's no server to run yourself — you authenticate with a Bearer API key and call the tools directly.
- Prompt: "Generate 4 subject lines for a 500-point reward expiring Friday"
- Run launch_test to send the subject line test to your loyalty segment
- Wait for engagement, then call get_results for lift between variants
- Use recommend_next to confirm the winning loyalty reward subject line
Getting started and free usage
Connect marginal to Continue as an MCP server, add your marg_live_ API key, and you can begin running AI agent email marketing experiments immediately. The free tier covers 100 experiments per month, enough to test loyalty reward subject lines across several campaigns.
See the marginal docs at https://marginal.sh/docs/ for the Continue setup steps and tool reference.
- Endpoint: https://marginal.sh/mcp
- Auth: Bearer API key (marg_live_...)
- Free tier: 100 experiments/month
- Docs: https://marginal.sh/docs/
Get started with marginal
marginal is a hosted email marketing MCP server at marginal.sh. Sign up free, create an API key, and connect https://marginal.sh/mcp from Cursor, Codex, or Claude Desktop.
- 100 experiments/month on the free tier
- Four MCP tools: generate_variants, launch_test, get_results, recommend_next
- Listed in the MCP Registry as sh.marginal/mcp