The short answer: ChatGPT, Claude, Gemini and Grok all draft good Substack Notes. None of them puts Notes onto Substack's schedule by itself. WriteStack is the Notes system around the draft: a weekly queue, Sync through your own browser extension, drafts in your voice, and stats showing which Notes brought subscribers. You can keep your favorite assistant for drafting and connect ChatGPT or Claude to WriteStack directly.
Based on OpenAI Help, Claude Help, Gemini Apps Help, xAI, each vendor's pricing page, WriteStack docs and Substack Help, checked 5 Nov 2026.
Most Substack writers already have an AI assistant open in another tab. It's where a long post turns into five openers, and where the "could I just build this myself?" thought shows up.
This page is the hub for that question. It compares WriteStack with the four assistants writers ask us about most, lays out what a homemade Notes scheduler really costs to build and keep running, and links to the full head-to-head pages.
We built WriteStack. Every claim about an assistant below links to that company's own pages, so you can check it yourself.
Quick answers
Can an AI assistant schedule Substack Notes? Not on its own. ChatGPT, Claude and Gemini can each run a prompt on a schedule, and the result stays inside that assistant as a chat, a notification or a draft (OpenAI Help, Claude Help, Gemini Apps Help). Substack Notes is not a built-in destination for any of them.
Can an assistant replace WriteStack? For drafting, mostly yes. For the queue, Sync, subscriber attribution and the Activity Center, no.
What does each cost? The main paid plans sit close together: ChatGPT Plus $20 a month, Claude Pro $20 monthly or $17 with annual billing, Google AI Pro $19.99 a month, and The X Subscription Premium (which includes Grok) $30 a month. WriteStack starts at $19.99 a month billed annually, or $23.99 monthly, with a 7-day free trial (WriteStack pricing).
Which assistants connect to WriteStack? WriteStack's docs list official setups for Claude, ChatGPT and Notion AI (WriteStack docs). The assistant drafts and queues Notes in WriteStack, and you click Sync to send them to Substack.
Compare WriteStack with each assistant
Each page covers that assistant's scheduling features, DIY costs, setup steps and dated prices.
- WriteStack vs ChatGPT for Substack Notes: ChatGPT tasks, the WriteStack ChatGPT app, and what a homemade scheduler on OpenAI's API involves.
- WriteStack vs Claude for Substack Notes: Claude Cowork scheduled tasks, Claude Code rebuilds, the three DIY architecture classes, and the Claude connector.
- WriteStack vs Gemini for Substack Notes: Gemini scheduled actions, Google AI Pro pricing, DIY costs, and why there is no official WriteStack Gemini connector today.
- WriteStack vs Grok for Substack Notes: Grok Automations, live X research, The X Subscription pricing, DIY costs, and why there is no official WriteStack Grok connector today.
The feature matrix
| ChatGPT | Claude | Gemini | Grok | WriteStack | |
|---|---|---|---|---|---|
| Draft Notes | Yes, from your prompt | Yes, from your prompt | Yes, from your prompt | Yes, from your prompt | Yes, from your own Notes and publication |
| Run a prompt on a schedule | Yes, ChatGPT tasks | Yes, Cowork scheduled tasks | Yes, scheduled actions | Yes, Grok Automations | Not needed; Notes wait in a queue on your weekly posting template |
| Hold a Notes queue | No | No | No | No | Yes |
| Get Notes onto Substack's schedule | No | No | No | No | Sync through the WriteStack browser extension |
| See which Notes brought subscribers | No | No | No | No | Yes, Notes Performance |
| Reply to comments and mentions in one feed | No | No | No | No | Yes, Activity Center |
| Official WriteStack connection | Yes, ChatGPT app | Yes, Claude connector | Not listed in WriteStack docs | Not listed in WriteStack docs | Built in |
| Main paid plan (monthly) | Plus, $20 | Pro, $20 ($17 annual) | Google AI Pro, $19.99 | X Subscription Premium, $30 | From $19.99 billed annually, $23.99 monthly |
Sources: OpenAI Help, claude.com/pricing, gemini.google/subscriptions, x.ai/pricing, x.ai/news/grok-automations, WriteStack pricing and docs, checked 5 Nov 2026. "No" in an assistant column means the assistant doesn't do it alone. A homemade setup can add some of these, at the cost covered below.
What assistants are good at
All four are strong drafting partners. Paste in a post and ask for six Notes that pull out its sharpest lines, or ask for a 400-word rant cut down to something that fits on a phone screen.
Each one has its own edge:
- ChatGPT has projects and scheduled tasks on Plus, so "every Monday, draft five Notes from my latest post" can run on its own and send you the results (ChatGPT pricing).
- Claude has Cowork and Claude Code on paid plans. Recurring Cowork tasks can run in Anthropic's cloud and leave drafts waiting (Claude Help).
- Gemini can schedule actions on a daily, weekly or monthly cadence, with up to 10 active at a time, and prepares the response before your delivery time (Gemini Apps Help).
- Grok searches the web and X live, which helps when a Note reacts to something happening today (xAI).
They're also flexible. One subscription covers research, editing, code and slides. If Notes are a small part of your week, that breadth matters.
Tip: Whichever assistant you use, give it three or four of your best Notes before you ask for anything new. Without real examples, drafts drift toward a generic tone.
What every assistant can't do alone
Put Notes on Substack's schedule
A scheduled prompt in ChatGPT, Claude or Gemini produces a draft inside that assistant. Getting it onto Substack still takes a paste, a script, or a product that holds a queue.
Substack does have its own free scheduler. On the web you click the calendar icon in the Notes composer, pick a date and time, and click Schedule (Substack Help). Any assistant plus Substack's scheduler is a real, free workflow. You paste and schedule each Note by hand.
Know which Notes worked
No assistant can see your Substack stats unless you paste them in. It doesn't know which of last week's Notes brought subscribers and which brought none. WriteStack's Notes Performance ranks your Notes by the free and paid subscribers they brought in (WriteStack docs).
Start from your real voice
Memory and custom instructions help, but they start from your description of how you write. WriteStack builds a writing style from your publication and studies your Notes from the last 180 days for patterns in openers, length, endings and topics (WriteStack docs). Writing rules get added as you edit, like and skip drafts.
DIY: what a homemade Notes scheduler costs
With an assistant writing the code, a basic Notes scheduler is within reach for a lot of writers. We haven't put hours on any of this because they depend on your skills and how much you want it to do. Here's the honest frame instead.
The three ways people build it
- Paste into Substack's native scheduler. The assistant drafts; you copy each Note into Substack and click Schedule. Free, slow and reliable.
- Connect the assistant to a Notes tool. The assistant talks to a product that holds the queue (WriteStack is one). You still Sync or publish through that product.
- Browser automation or session-cookie scripts. A browser agent, a custom script or a third-party MCP server drives Substack's web app with your login or cookie. Fastest to a first post. You own security and breakage.
Build, run, maintain
| Cost | What it looks like |
|---|---|
| Build time | Working out how to post to Substack, store a queue, handle images and run it on a timer. A first version can come together fast. A version you trust with a week of Notes takes longer. |
| Monthly run cost | Your assistant plan (about $20 to $30 a month for the main tiers above), plus API usage if your script calls a model directly. API usage is billed separately from chat plans. |
| Maintenance | Homemade scripts usually drive Substack's web app. When that app changes, the script can stop working until you fix it. |
| Security | Most homemade setups need your Substack login or session cookie stored somewhere your script or browser tool can reach. |
| Attribution | Still missing unless you also build a way to match new subscribers to individual Notes. |
The money is the small part
Model APIs are cheap for short text, and Notes are short. The token bill for drafting a week of them is a small line item. The real cost is your time, first to build it and then every time Substack changes something. The first sign of breakage is often a Note that never went out.
Keeping Substack connected safely
A session cookie lets whoever holds it act as you on Substack until it expires. If it sits on a server or in a shared config file, you trust everything that can read it. WriteStack schedules Notes from your own browser through the WriteStack extension, using the Substack account you're logged in to there (Sync docs).
Struggling to stay consistent on Substack?
Batch and queue your Substack Notes in minutes, track which Notes convert subscribers, and grow without burning out.
Using an assistant with WriteStack
You don't have to choose. Keep the assistant for thinking and drafting, and let WriteStack handle everything after the draft.
- Connect WriteStack in ChatGPT or Claude (or Notion AI). The setup guides walk through each one: Connect ChatGPT, Connect Claude, Connect Notion.
- Ask something like "Draft three Notes about my latest post and queue them."
- Open WriteStack on your computer, go to My Notes → Scheduled notes, and click Sync N scheduled notes to Substack.
Notes queued from an assistant wait in WriteStack until you Sync them from a computer with the extension installed and Substack logged in. Once synced, Substack holds each scheduled Note and publishes it at its time (Sync docs). The connection never pushes Notes to Substack by itself.
The connection runs on WriteStack's MCP server, included on Standard and Enterprise (shown as "Claude MCP" on the pricing table). More detail: WriteStack MCP and our Substack MCP server guide. Step-by-step walkthroughs: schedule Substack Notes with ChatGPT and schedule Substack Notes with Claude.
Using Gemini or Grok? Draft there, then paste into WriteStack's queue or Substack's scheduler.
On Standard you can also send each Note to LinkedIn, X or Threads through your Buffer account (cross-posting docs). Buffer is a friendly partner here.
Pricing snapshot (checked 5 Nov 2026)
| Plan | Price | What it covers for Notes |
|---|---|---|
| ChatGPT Plus | $20/month | Drafting, projects, scheduled tasks |
| Claude Pro | $20/month billed monthly, or $17/month with annual billing | Drafting, Cowork, scheduled tasks, connectors, Claude Code |
| Google AI Pro | $19.99/month ($199.99/year) | Drafting in Gemini, scheduled actions |
| The X Subscription Premium | $30/month | Grok with SuperGrok benefits, plus X Premium+ and Cursor |
| WriteStack Hobbyist | $19.99/month billed annually ($239.88/year), or $23.99 monthly | Queue of 20 Notes, AI drafts in your voice, the Coach |
| WriteStack Standard | $24.99/month billed annually ($299.88/year), or $32.99 monthly | Queue of 100, MCP for ChatGPT and Claude, Activity Center, subscriber attribution, Buffer cross-posting |
| WriteStack Enterprise | $79.99/month billed annually ($959.88/year), or $99.99 monthly | Unlimited queue and AI credits, advanced Notes search |
Sources: OpenAI Help on ChatGPT Plus, Claude pricing, Google AI plans, The X Subscription, WriteStack pricing, WriteStack plans and limits. US prices before tax. Every WriteStack plan has a 7-day free trial and can be canceled anytime.
Cheaper tiers exist too, such as Google AI Plus at $4.99 and The X Subscription Plus at $8 a month.
Who should pick which
Stick with your assistant and Substack's own scheduler if you post a few Notes a week, don't mind pasting each one, and don't need to know which Notes bring subscribers.
Build your own if you enjoy the project, are comfortable keeping a Substack login secure, and accept that you'll fix it when Substack changes.
Use WriteStack, with ChatGPT or Claude connected if you like, if Notes are a growth channel for you. You get a weekly queue, drafts in your voice, one feed for replies, and a clear view of which Notes turned readers into subscribers.
FAQ
Which AI assistant is best for writing Substack Notes?
The one you already use well. All four draft good Notes when you give them real examples of your writing. Pick ChatGPT or Claude if you want to queue Notes into WriteStack from the chat, since those have official WriteStack setups.
Can Gemini or Grok connect to WriteStack?
WriteStack's docs list setups for Claude, ChatGPT and Notion AI. Gemini and Grok aren't on that list today, so draft there and paste into WriteStack or Substack.
Does any assistant post Notes to Substack directly?
Not by itself. Scheduled prompts produce drafts inside the assistant. With WriteStack connected, ChatGPT or Claude can queue Notes in WriteStack, and you click Sync to put them on Substack's schedule.
Is it cheaper to build my own scheduler with AI?
The subscription and API bill can be lower. The cost moves to your time: you build it, keep your Substack login secure, and fix the script when Substack changes.
Do I need an assistant subscription to use WriteStack?
No. WriteStack drafts Notes on its own. You only need an assistant if you want to work from inside it, and the connection needs a WriteStack plan with MCP (Standard or Enterprise).
The short version
AI assistants are where Notes get drafted. WriteStack is where those Notes get queued, synced through your own browser, written in your voice and measured by the subscribers they bring. Keep the assistant you like, and let WriteStack handle everything after the draft. See WriteStack plans and the 7-day free trial.
Also compare: WriteStack vs ChatGPT for Substack Notes · WriteStack vs Claude for Substack Notes · WriteStack vs Gemini for Substack Notes · WriteStack vs Grok for Substack Notes · Best Substack scheduling tools · Substack MCP server guide
Sources
All checked on 5 Nov 2026.
- OpenAI Help, Tasks in ChatGPT
- OpenAI Help, What is ChatGPT Plus?
- OpenAI, ChatGPT pricing
- Claude, Pricing
- Claude Help, Schedule recurring tasks in Claude Cowork
- Claude Help, Use Claude Cowork on web, desktop, and mobile
- Gemini Apps Help, Schedules in Gemini Apps
- Google, Google AI plans
- xAI, Grok
- xAI, Automations in Grok
- xAI, Introducing The X Subscription
- Substack Help, Getting started on Substack Notes
- WriteStack, Pricing
- WriteStack, MCP
- WriteStack docs, Connect ChatGPT
- WriteStack docs, Connect Claude
- WriteStack docs, Connect Notion
- WriteStack docs, Sync
- WriteStack docs, Plans and limits
- WriteStack docs, Writing style
- WriteStack docs, Find your best Notes
- WriteStack docs, Cross-posting with Buffer