MCP Server

Backstroke MCP Server

Customer Preview

The predictive layer for your marketing AI.

Connect Backstroke to Claude, or any AI assistant, and get subject lines, heroes, and content predicted to perform. Learned from 10,000 ecommerce brands, returned right in your prompt.

Last updated: July 2026
Customer Preview This page describes how the Backstroke MCP Server works and what it can do. Access is rolling out to Backstroke customers first. Request access below and we will walk you through getting connected.

Overview

The Backstroke MCP Server connects your AI assistant to Backstroke's prediction models. Most marketing connectors give an assistant read access to your own account data. Backstroke returns something your account cannot produce on its own: a read on what will actually perform, learned from real email outcomes across 10,000 brands.

You ask in plain language. Backstroke answers right in your prompt, and with your approval it can write the winner back into your email platform. Your work stays in the assistant you already use, and Backstroke stays the prediction engine behind it.

How it works

Backstroke MCP is a hosted endpoint your assistant connects to. You sign in once. From then on, your assistant can call Backstroke's tools whenever you ask.

  1. You ask. Describe what you are working on, such as subject lines for an email or which hero wins for your audience, in natural language.
  2. Backstroke predicts. Your request runs against models learned from outcomes across 10,000 brands, not your account alone.
  3. You decide. The answer comes back in your prompt. Anything that writes to your email platform pauses for your explicit approval first.

You connect once. As new tools ship, they appear in your assistant automatically, with no reinstall and no reconnect.

// ask → predict → your approval → done

The tools

Backstroke's tools arrive in your assistant in two groups, split by what they are allowed to touch. Read-only tools are always allowed. Write tools ask for your approval every time. Tools marked Live work today. Tools marked Coming are on the way.

Backstroke MCP tool list in Claude
// ask your assistant to list Backstroke's tools

Read-only

Always allowed

These tools read and predict. They never change anything in your systems.

predict_subject_lines Live

Generate a set of subject lines and preheaders predicted to perform, each with a one-line why.

predict_subject_lines output in Claude
// predict_subject_lines: a set predicted to perform, from an email's content
predict_subject_lines_for_my_audience Live

The same set, tuned per segment and written in your brand voice.

predict_subject_lines_for_my_audience cohort output in Claude
// predict_subject_lines_for_my_audience: the same set, tuned per cohort
read_campaign_content Live

Read an existing campaign's real content, its hero, products, and copy, so every suggestion is about that email and not just its name.

score_hero_generic Live

Drop in candidate hero images and get them ranked by predicted performance, with the audience each one wins with.

score_hero_for_my_audience Live

Score heroes against your actual audience and get the winner, with the segments it wins with.

generate_predictive_heroes Coming

Generate the hero or heroes predicted to perform, either a single winner or a set routed to different cohorts as one personalized block.

report_lift Coming

Read your results and return campaign lift with a board-ready roll-up.

Write

Approval required

These tools change something in your email platform. Your assistant asks before each one, every time. Nothing sends on its own, and writes create drafts you review.

push_subject_lines_to_klaviyo Live

Write your per-segment subject lines into Klaviyo as draft campaign variants, after you confirm.

make_campaign_predictive Coming

Turn a Backstroke campaign predictive by attaching the winning hero set and updating the email.

create_klaviyo_ucb Coming

Build a Klaviyo content block that routes the predictive heroes per segment.

update_brand_settings Coming

Teach the agent a rule once, such as never say discount, and it updates your brand config so every future suggestion respects it.

Prediction, not generation

Backstroke works in two verbs, and the distinction matters. Subject lines are generated. You get a set predicted to perform, written from patterns across 10,000 brands, rather than a ranking of lines you already have. The edge is the model underneath, not a guaranteed winner.

Heroes are scored. Candidate images are ranked against a model of your actual audience, and you get the winner along with the segments it wins with. That is the thing a generic generator cannot do, because it has no read on your list. Hero scoring returns a ranked read against your audience, with expected lift added once it is validated against real results.

What you can ask

With the Live tools, you can ask your assistant things like these today:

Subject lines

Here is my Friday sale email. Give me subject lines that will perform.
Write subject lines for the spring sale, tuned to my segments and in our brand voice.

Heroes and content

Read campaign 4659 and base the suggestions on its actual content.
Score these hero images against my audience and tell me which one wins.

Activate

Push those subject-line variants to Klaviyo as drafts for me to review.

Generating predictive heroes and pushing the winner live are coming next, and will answer the same way, right in your prompt.

Staying in control

The agent proposes. You commit. The permission model is built into how the connector works:

  • Read-only by default. Every prediction tool only reads and answers. Nothing in your systems changes.
  • Writes always ask first. Anything that touches your email platform pauses for your explicit approval, every time. Writes create drafts, and nothing sends on its own.
  • Nothing stored. Your campaign content is processed to answer your question, not retained.
  • Connect once, revoke anytime. Sign in with OAuth. Every call resolves to your account, and you can disconnect whenever you want.
  • SOC 2 Type II compliant. Backstroke maintains SOC 2 Type II controls across its platform.

Roadmap

The Live tools are the first rung. What is ahead:

  • Any assistant. Claude today, other AI assistants next, from the same connection.
  • The full hero workflow. Read the campaign, score heroes for your audience, and generate the predictive set, then activate the winner where you work.
  • The whole play in one command. Ask once and the agent runs the sequence for you, reading, scoring, generating, and writing, holding for your approval at each write.

Access

Customers get first access.

Backstroke MCP access is rolling out to Backstroke customers first. Fill out the form and we will walk you through getting connected.

Request access →