Posting Substack Notes every day is the new growth tax. Stay consistent and your subscribers climb. Go quiet for a few days and the feed forgets you. But writing and scheduling 21 Notes a week by hand is roughly 3.5 hours of copy, paste, pick a time, repeat. And there is no official Substack API to automate any of it, so most tools are either browser extensions that click around the page for you or developer scripts you have to clone and run yourself.
The Substack MCP server closes that gap. It connects Claude straight to your Substack so you can write Notes in proven formats, schedule a week of them, draft full articles, and pull your real numbers, all from a normal Claude conversation. The same batch that used to eat 45 minutes of manual scheduling takes about 2. We run our own GenAI Unplugged publication on it. This guide covers what it is, every tool it gives you, how to connect it in about five minutes, and the prompts that make it useful on day one.
The short answer
The Substack MCP server is a hosted server that connects Claude (Desktop, Cowork, or Code) to your Substack. Once linked, Claude can write and schedule Notes, draft full articles, and read your stats, using your own session cookie, never your password. The notes tools are free for GenAI Unplugged subscribers, and setup takes about five minutes with no code.
Why this exists: Substack has no official API
Here is the load-bearing fact. Substack does not publish an official API. There is no documented, supported way for an outside app to post a note or pull your stats. That is why most "Substack automation" lives in browser extensions that click around the page for you, or in developer scripts you have to clone and run yourself.
An MCP server is a cleaner answer. MCP, the Model Context Protocol, is the standard way to give an AI assistant new tools. A Substack MCP server exposes a set of Substack actions as tools Claude can call. You ask Claude in plain English, Claude calls the tool, and the action happens in your Substack. No clicking, no scripts, no terminal.
The version covered here is hosted, so you do not run anything. You point Claude at it, authenticate once, and the tools show up inside your conversation.
What you can do: every tool, grouped by job
The server gives Claude a focused set of tools. Here is what they do, organized by the job you are trying to get done, with an example prompt for each group.
Write and schedule notes
These are the workhorse tools. Claude can create a note as a draft, schedule it for a future time, publish it now, edit the text of an existing note, or delete one. There is also a bulk scheduler built for queueing a whole week of notes in a single pass.
"Write five Substack Notes from my last article, space them across the next five weekdays at 9am, and schedule them all."
Claude drafts the notes, shows you the schedule, and on your go-ahead calls the scheduler so they land in your Substack queue. No copy and paste.
Read and analyze your notes
Claude can list your recent notes with their engagement and pull the detail of any single note, including reactions, restacks, and replies. That turns "which of my notes actually worked" into a question you can just ask.
"List my notes from the last two weeks and tell me which angle got the most restacks."
Check your dashboard and subscriber stats
Claude can read your publication dashboard and your subscriber totals, free and paid, without you opening the Substack stats page.
"What are my current subscriber numbers, and how many are paid?"
List posts and pull post stats
Claude can list your posts by status, published, draft, or scheduled, and pull detailed traffic and engagement for a specific post so you can see what is landing.
"List my last ten published posts, then pull the open and click stats for the top one."
Draft and update full articles from Claude Cowork
This is the part no notes scheduler does. Claude can create a full article draft in your Substack and update an existing one, title, subtitle, body, and section. Pair it with Claude Cowork and you can go from an outline to a finished draft sitting in your Substack, ready for your review.
"Turn this outline into a full Substack draft in my publication, set the subtitle, and leave it unpublished for me to review."
Claude writes the draft and pushes it. It never hits publish for you, so you always get the last look.
Write in our proven note formats
The server also ships our content playbook as tools, so Claude does not start from a blank page. viral_notes_creator hands Claude 13 named note formats, each with a clear "use when" and a paste-ready prompt, built on an analysis of thousands of high-performing Substack Notes. Ask for one format or the whole set, write the note, then schedule it. That is the loop nothing else closes: generate in a proven format, then schedule, in one conversation.
The 13 formats, and when each one works:
- Pure Take — you have a strong opinion and want to state it plainly, no hedging.
- Caught-Myself Note — name a behavior your audience does but does not talk about.
- Contrarian Take — challenge conventional wisdom with a sharp counterpoint.
- Hidden Truth — surface an overlooked truth with a curiosity gap.
- Honest Struggle — a real problem you fought, and the thing that finally worked.
- Permission Slip — give readers permission to stop performing.
- Framework / Process — name a clear, repeatable process worth saving.
- Screenshot-Worthy Truth Bomb — one insight someone can screenshot with no context.
- Specific Result Note — a tactic plus the real number it produced.
- Idea Helix — a note rooted in a real product-to-problem chain.
- MOAT Storyline — reinforce your unique narrative without announcing it.
- Voice + Format Rules — the constraint set that makes any note sound like you.
- Engagement Picker — decide whether a note should earn likes or comments before you write it.
"Use the Screenshot-Worthy Truth Bomb format to write three Notes from this article, then schedule them across next week."
Two more content tools come along: substack_toc builds a numbered table of contents with working anchor links for a long article, and substack_live_recap turns a Substack Live transcript into a publish-ready recap. viral_title_variants (PluggedIn) generates a ranked set of high-CTR titles grounded in our own best performers.
Free vs PluggedIn: what each tier unlocks
The server is tiered to your GenAI Unplugged subscription. Free covers everything most writers need day to day. PluggedIn, the paid tier, adds the deeper analytics and full article drafting.
| Capability | Free (any subscriber) | PluggedIn (paid) |
|---|---|---|
| Create, schedule, edit, publish, delete Notes | Yes | Yes |
| Bulk-schedule Notes | Up to 7 per batch | Unlimited (up to 30) |
| List and read your Notes with engagement | Yes | Yes |
| Dashboard and subscriber totals | Yes | Yes |
| List posts by status | Yes | Yes |
| Read existing drafts and sections | Yes | Yes |
| Viral notes creator (13 formats) | Yes | Yes |
| Substack TOC and Live recap tools | Yes | Yes |
| Viral title variants | No | Yes |
| Subscriber growth over time | No | Yes |
| Per-post traffic and engagement stats | No | Yes |
| Create and update full article drafts | No | Yes |
Substack MCP vs the other ways to automate Substack
There is no official Substack API, so every tool works around that. Here is how the Substack MCP server compares to the other options, including our own SubflowAI.
| Approach | Setup | Write in proven formats | Bulk schedule | Draft full articles | Cost |
|---|---|---|---|---|---|
| Substack MCP (this guide) | About 5 minutes, no code | Yes, 13 formats | Yes (7 free, 30 paid) | Yes, from Claude Cowork | Free for subscribers |
| Open-source dev scripts | Clone a repo, run a server | No | Some | Read-heavy, limited | Free, you self-host |
| Notes scheduler extensions | Install a browser extension | No | Yes, notes only | No | Freemium |
| SubflowAI (our product) | Install, zero config | Yes, managed | Yes, visual calendar | No | Freemium |
| Doing it by hand | None | No | No, about 45 minutes a batch | No | Your time |
The short version: the dev scripts need a terminal, the notes extensions only schedule, and doing it by hand does not scale. The Substack MCP is the one that writes in proven formats, schedules in bulk, and drafts full articles, all from inside Claude. If you would rather not wire anything up at all, SubflowAI is the done-for-you version with a visual calendar.
Ready to connect Substack to Claude?
Free for GenAI Unplugged subscribers. No terminal, no code, about five minutes to set up.
Connect Substack to ClaudeHow to connect Substack to Claude
Setup takes about five minutes and works with Claude Desktop, Claude Cowork, and Claude Code. The walkthrough below goes through every step on screen.
Step 1: Get your session cookie and subdomain
You need two values, both pasted into your config once.
For the session cookie:
- Open Chrome and go to any Substack page while logged in.
- Press F12, then open the Application tab, then Cookies, then
.substack.com. - Find
substack.sidand copy its value (it starts withs%3A).
For your subdomain, look at your Substack URL. In https://yourname.substack.com, the part before .substack.com is your subdomain.
Step 2: Add the config for your client
Claude Desktop or Claude Cowork. Paste this into ~/Library/Application Support/Claude/claude_desktop_config.json on macOS, or %APPDATA%\Claude\claude_desktop_config.json on Windows. It uses mcp-remote, so you need Node.js installed.
{
"mcpServers": {
"substack": {
"command": "npx",
"args": [
"-y",
"mcp-remote",
"https://substackmcp.genaiunplugged.com",
"--header",
"X-BYOK-Substack-Cookie:PASTE_YOUR_SID_HERE",
"--header",
"X-BYOK-Substack-Subdomain:PASTE_YOUR_SUBDOMAIN_HERE"
]
}
}
}
Claude Code. Paste this into ~/.claude/settings.json.
{
"mcpServers": {
"substack": {
"type": "http",
"url": "https://substackmcp.genaiunplugged.com",
"headers": {
"X-BYOK-Substack-Cookie": "PASTE_YOUR_SID_HERE",
"X-BYOK-Substack-Subdomain": "PASTE_YOUR_SUBDOMAIN_HERE"
}
}
}
}
Replace PASTE_YOUR_SID_HERE with your session cookie and PASTE_YOUR_SUBDOMAIN_HERE with your subdomain (for example, genaiunplugged).
Step 3: Authenticate with a magic link
Save the config and fully restart your client. The app opens a browser window for you. Enter the email you use to subscribe to GenAI Unplugged on Substack, and we send a magic link. Click it, and you bounce back into Claude with the tools loaded. In Claude Code, run /mcp or just ask Claude to use a Substack tool, and it opens the browser for you.
One thing to get right: authenticate with your GenAI Unplugged subscriber email, not the email on your Claude account. That subscriber email is the identity the server checks for your tier.
Use-case recipes
Once it is connected, these are the prompts that earn their keep.
- Batch a week of notes. "Read my latest article, write seven Notes across different angles, and schedule one per day at 9am next week."
- Repurpose a post into a thread of notes. "Pull my top post from last month and turn its three best points into three standalone Notes, scheduled two days apart."
- Monday numbers check. "Give me my subscriber totals, my best post this week by opens, and which Note got the most replies."
- Outline to draft. "Here is an outline. Write it as a full Substack draft in my publication and leave it unpublished."
- Clean up the queue. "List my scheduled Notes and delete the two that overlap on the same topic."
Is it safe?
Short version: you stay in control, and your password never enters the picture.
- No password, ever. You authenticate with a magic link to your email. The server never asks for or stores your Substack password.
- Your cookie, your machine. Your
substack.sidcookie lives in your local config and is sent with each request. It is never stored or logged on the server. Log out of Substack and the cookie stops working. - Drafts, not surprise publishes. Claude creates and updates article drafts but does not publish full articles for you. You always get the final review before anything goes live.
- Conservative limits. Because there is no official Substack API, the server keeps request limits deliberately low to protect your account from looking automated.
Troubleshooting
A few things trip people up. Most fixes take a minute.
- It will not connect, or the login page hangs. Clear the client auth cache. Fully quit Claude (not just the window), then remove the
~/.mcp-authfolder on macOS or Linux, or%USERPROFILE%\.mcp-authon Windows. Reopen and re-authenticate. - The same email stopped working after a few tries. The magic-link endpoint is rate limited per hour. Wait an hour, or test with a different subscriber email.
- The magic link says invalid or expired. Some corporate and .edu mail scanners pre-open links. Click the link yourself from the original email, and use the Confirm button on the page rather than relying on a preview.
- Tools do not appear. Check your config JSON is valid (no trailing commas), confirm your cookie has not expired, and make sure you fully quit and reopened the app.
Go deeper
- SubflowAI: the fastest way to schedule Substack Notes if you want a done-for-you product instead of wiring it up yourself.
- The full Substack Notes workflow with Claude Cowork, the deep walkthrough this guide is built on.
- Claude Code extensions explained, the wider map of skills, MCP servers, and more.
- Browse all our products.
Frequently asked questions
Is there a Substack API?
There is no official, public Substack API. Substack has internal endpoints its own apps use, but nothing documented or supported for developers. The Substack MCP server is a community tool that talks to those endpoints on your behalf using your own session cookie, so Claude can read and write your Substack without an official API.
Can Claude post to Substack?
Yes. With the Substack MCP server connected, Claude can create, schedule, edit, publish, and delete Substack Notes directly. It can also create and update full article drafts. Claude never publishes a full article on its own, it leaves drafts for you to review and send.
Can Claude write a full Substack article?
Yes. Using Claude Cowork or Claude Desktop with the Substack MCP server, Claude can draft a complete article from your notes or outline and push it to your Substack as a draft. You review and publish it yourself. Full article drafting is a PluggedIn (paid) feature.
Is the Substack MCP server safe? Does it store my password?
It never sees or stores your Substack password. You authenticate with a magic link to your email, and you pass your own Substack session cookie through your local config. The cookie is sent with each request and is never stored or logged on the server. You can revoke it any time by logging out of Substack.
Is the Substack MCP server free?
The notes tools and the core read tools are free for any GenAI Unplugged subscriber. Advanced tools like subscriber growth over time, per-post analytics, and full article drafting are unlocked for PluggedIn members on the paid Substack tier.
Do I need to code to use it?
No. You paste one config block into Claude Desktop, Claude Cowork, or Claude Code, add your session cookie and subdomain, restart, and click a magic link. There is no terminal, no git clone, and no server to run. Setup takes about five minutes.
Is the Substack MCP against Substack's terms of service?
Substack has no official API, so any automation tool, including this one, uses internal endpoints that are not officially supported. Use it at a reasonable cadence and at your own risk. The server enforces conservative rate limits to keep activity looking human, but you are responsible for how you use it. You stay in control, and you can revoke access any time by logging out of Substack.
How many Substack Notes can I schedule at once?
On the free tier you can bulk-schedule up to 7 Notes per batch, which covers a full week one a day. PluggedIn members can bulk-schedule up to 30 in a single call. Either way the server spaces the calls out to avoid tripping Substack's bot detection.
Can I use the Substack MCP on the free Substack plan?
Yes. The MCP works with any Substack publication. Tiering here is about your GenAI Unplugged subscription, not your Substack plan: the notes and core read tools are free for any GenAI Unplugged subscriber, and advanced analytics, title variants, and full article drafting unlock for PluggedIn members.
What is the viral notes creator?
It is a free tool that hands Claude 13 named Substack Note formats, like Contrarian Take, Permission Slip, and Screenshot-Worthy Truth Bomb, each with a clear use-when and a paste-ready prompt built from an analysis of thousands of high-performing Notes. Ask Claude for a format, write the Note, then schedule it, all in one conversation.