Connect Substack to Claude: Substack MCP

💡 No install? Use cloud.anythingmcp.com directly. Sign in, click Connectors → Substack, paste the publication's URL, and connect Claude — done. No Docker, no git clone, no local server.

Substack + Claude

Read a Substack publication from Claude: posts, full-text search of the archive, comments and the RSS feed, through the same public endpoints Substack's own site uses. 7 tools, no API key and no Substack login.

What you can ask Claude

• "What are the ten latest posts, with date and whether each one is free or paid?" Uses substack_list_posts; each post carries its audience.
• "Find every post in the archive that talks about pricing." Uses substack_search_posts.
• "Summarise post 148234567 in five bullet points." Uses substack_get_post_by_id.
• "What are readers saying under the latest post?" Uses substack_list_posts to find it, then substack_get_comments.
• "Which of this year's posts are podcast episodes?" Uses substack_list_posts; each post carries its type (newsletter, podcast or thread).
• "Give me the RSS feed so I can see what's new since Monday." Uses substack_get_rss_feed.

What you need

• The publication's base URL, for example https://lennysnewsletter.substack.com, in SUBSTACK_PUBLICATION_URL. That's all.
• No API key and no account: the connector reads public endpoints, so it sees what a logged-out visitor sees.
• One publication per connector. To read a different one, change SUBSTACK_PUBLICATION_URL.

Step 1 — Set the publication URL

1. There is no key and no Substack login. Set SUBSTACK_PUBLICATION_URL to the publication's home address, with nothing after the domain: https://yourname.substack.com or a custom domain such as https://www.lennysnewsletter.com.
2. A profile link (https://substack.com/@handle), a note link or a post link does not work. From a profile, open the publication shown there and copy the address bar up to the domain. In an app share link open.substack.com/pub/NAME/p/..., NAME is the subdomain: use https://NAME.substack.com.
3. Start with substack_list_posts (newest first, or sort=top for the most liked), then substack_get_post_by_id or substack_get_post_by_slug (the part after /p/ in a post link) for the full text. substack_find_publication_by_handle turns an @handle into the writer's publication address.

The connector reads the public JSON endpoints Substack's own site uses (Substack has no documented public API), so it sees what a signed-out visitor sees: paid posts show their preview only. Lists take limit (up to 50) and offset. A 404 on every tool means there is no publication at the configured address; an HTML page instead of JSON means the address is a profile or not a Substack site.

Step 2 — Install the adapter

On Cloud, open Connectors → Substack and paste the URL. To self-host:

curl -fsSL https://raw.githubusercontent.com/HelpCode-ai/anythingmcp/main/docker-compose.quickstart.yml -o docker-compose.yml
printf 'JWT_SECRET=%s\nENCRYPTION_KEY=%s\n' "$(openssl rand -hex 32)" "$(openssl rand -hex 32)" > .env
docker compose up -d

Step 3 — Add the connector in Claude

Your server URL: in AnythingMCP, open MCP Servers → the server this connector is on, and copy its URL (https://cloud.anythingmcp.com/mcp/…). Use it wherever this guide shows YOUR_SERVER_ID.

On claude.ai (the connector then also appears in Claude Desktop):

1. Open claude.ai/customize/connectors.
2. Click +, then Add custom connector.
3. Name it AnythingMCP and enter the URL https://cloud.anythingmcp.com/mcp/YOUR_SERVER_ID.
4. Click Add, then Connect. Sign in to AnythingMCP and choose which of your MCP servers Claude may use.

In Claude Code, run the command below, then type /mcp in a session and choose Authenticate:

claude mcp add --transport http anythingmcp https://cloud.anythingmcp.com/mcp/YOUR_SERVER_ID

Self-hosting? Use your own AnythingMCP URL instead of cloud.anythingmcp.com. For claude.ai it has to be reachable from the internet, because Claude connects from Anthropic's servers, not from your computer.

All tools below appear in your chat — start typing prompts.

Available tools

Troubleshooting

• Every tool fails. Check SUBSTACK_PUBLICATION_URL: it has to be the publication's home address, starting with https:// and with nothing after the domain. A profile (substack.com/@handle), note or post link does not work; open the publication from the profile and copy its address up to the domain.
• A paid post comes back cut short. The connector does not log in, so it gets what a non-subscriber gets. Paid-only content is not unlocked.
• A search returns nothing. substack_search_posts returns an empty list when no post matches. Try fewer or broader words.
• Requests start failing after many calls in a row. Substack does not publish rate limits and throttles heavy traffic. Space out bulk reads, around one request per second.

FAQ

Can Claude publish posts or reply to comments on Substack? No. Substack has no public API for writing, so the connector only reads. Creating posts, managing subscribers and moderating comments stay in Substack's own interface.

Does it work with Claude Code as well as Claude Desktop? Yes. A custom connector you add on claude.ai is also available in Claude Desktop, and Claude Code adds the same URL with claude mcp add --transport http. Custom connectors are available on every Claude plan; the Free plan allows one, which is enough because a single AnythingMCP connector carries all your connectors.

Is it free? The Substack side needs no key and costs nothing. AnythingMCP is open source under AGPL-3.0, so self-hosting is free, including commercial use inside your own company; AnythingMCP Cloud comes with a 7-day free trial.

Is my data stored by AnythingMCP? The connector reads public content and holds no Substack credentials. When Claude uses a tool, AnythingMCP fetches the content and passes it to Claude, and the call is recorded in your workspace's audit log. AnythingMCP Cloud is hosted in Frankfurt, Germany.

Next steps

• Connector landing page
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