You already run your Substack Notes through SubflowAI. This guide shows you how to let an AI assistant, Claude Desktop, Claude Code, Claude Cowork, or ChatGPT, drive SubflowAI for you: "check how full my week is and fill the empty slots," "turn this article into five Notes and schedule them," "clean up my drafts." The assistant does the thinking, SubflowAI does the work on your Substack.
There are two ways to connect. Most people want the first one.
Before you start
- SubflowAI installed and set up (you can already schedule Notes with it).
- An active paid SubflowAI license (a trial will not unlock the AI connection).
- An AI client that supports MCP connectors: Claude Desktop, Claude Code, Claude Cowork, or ChatGPT.
When you connect, you agree to the SubflowAI, SubstackMCP, and GenAI Unplugged Terms and Privacy Policies. You will confirm this with a checkbox on the sign-in page before pairing.
Mode 1: Relay (recommended, nothing to paste)
This is the zero-setup path. Your Substack login never leaves Chrome. The assistant sends a request, SubflowAI runs it right there in your browser, and sends back the result. The one trade-off: your browser has to be open for a live request to run. (Notes you have already scheduled still publish on time even if Chrome is closed, because Substack schedules them natively.)
Step 1. Add the connector in your AI client. In Claude or ChatGPT, add a connector and point it at:
substackmcp.genaiunplugged.com
Step 2. Click "Connect with SubflowAI".
On the sign-in page that opens, tick the box to agree to the terms, then click the Connect with SubflowAI button. It shows you a short 8-character code (like ABCD-EFGH).
Step 3. Paste the code into SubflowAI. Open SubflowAI, go to Settings → Connect, paste the code into the box, and click Connect. That is it. Return to your AI client and try a command:
"Is my Substack Notes calendar full next week? If not, draft Notes from my last article and fill the open slots."
To disconnect: Settings → Connect → Disconnect all agents. Access is revoked instantly.
Mode 2: BYOK for 24/7 agents (Chrome can be closed)
Relay mode only runs while Chrome is open. If you want an agent that runs on a schedule with your browser closed, for example a Claude Code or Cowork job that fills your slots every morning, use BYOK (bring your own key) mode instead.
Here is the important part: AI "custom connectors" cannot pass header keys, so there is nowhere to put your session cookie in the connector UI. Instead you paste a small config block into your client's config file, using --header flags. SubflowAI builds that entire block for you.
Step 1. Copy the config from SubflowAI. In SubflowAI, go to Settings → Connect → Advanced: 24/7 cloud agents (BYOK) and click Copy full MCP config. SubflowAI fills in your session cookie and publication subdomain automatically. The block looks like this:
{
"mcpServers": {
"substack": {
"command": "npx",
"args": [
"-y",
"mcp-remote",
"https://substackmcp.genaiunplugged.com",
"--header",
"X-BYOK-Substack-Cookie:YOUR_SESSION_IS_FILLED_IN",
"--header",
"X-BYOK-Substack-Subdomain:yourpublication"
]
}
}
}
If you see PASTE_YOUR_SUBDOMAIN in the copied block, set your Publication Subdomain in Settings → General first, then copy again.
Step 2. Paste it into your client's config file.
- Claude Desktop (macOS):
~/Library/Application Support/Claude/claude_desktop_config.json - Claude Desktop (Windows):
%APPDATA%\Claude\claude_desktop_config.json - Claude Code: add the same
mcpServersentry to your Claude Code MCP config.
Requires Node.js / npx on your machine.
Step 3. Restart your client.
Fully quit and reopen Claude Desktop (or restart Claude Code). The substack tools appear and now work even when Chrome is closed, because the server talks to Substack directly with the session you provided.
Heads up on cookie expiry: a Substack session cookie expires after about 30 days or when you log out of Substack. When it does, tool calls fail with an auth error. Re-copy the config from SubflowAI and paste the fresh value.
Which mode should I pick?
| Relay (Mode 1) | BYOK (Mode 2) | |
|---|---|---|
| Setup | Paste one code | Paste one config block |
| Works with Chrome closed | No | Yes |
| Where your Substack login lives | Only in Chrome | In your own client config file |
| Best for | Everyday, hands-on use | Scheduled 24/7 cloud agents |
Start with Relay. Move to BYOK only when you specifically want agents running while your browser is closed.
What you can ask your assistant to do
Once connected, your AI assistant can plan, write, schedule, edit, and clean up your Substack Notes through SubflowAI, plus use SubflowAI's own tools:
"Check my week's capacity, find the open slots, and distribute these five Notes across them."
"Repurpose this article into a set of Notes in my voice, then schedule them one a day."
"List my scheduled Notes and delete the duplicate."
You stay in control. You can watch what it does in SubflowAI, and disconnect any time.