Connect Substack to Microsoft Copilot via MCP

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

Substack + Microsoft Copilot

Read a Substack publication from Copilot: 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 Copilot

• "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 Microsoft Copilot

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.

Microsoft Copilot uses MCP servers through agents built in Copilot Studio: you add AnythingMCP to an agent as a tool, then publish the agent to Microsoft 365 Copilot and Teams. Copilot Studio connects from Microsoft's cloud over Streamable HTTP, which AnythingMCP supports.

1. In Copilot Studio, open your agent (or create one), go to Tools and choose Add a tool → New tool → Model Context Protocol.
2. Enter a Server name (for example AnythingMCP), a Server description that says what the connector does, and the Server URL https://cloud.anythingmcp.com/mcp/YOUR_SERVER_ID. Copilot Studio uses the description to decide when to call the server.
3. Under authentication, choose API key, set Type to Header and the header name to X-API-Key, then select Create.
4. In Add tool, choose Create a new connection, paste an MCP API key from AnythingMCP (MCP Servers → your server → API keys) and select Add to agent.
5. Try it in the agent's Test pane: ask for something that needs the Substack tools.
6. Select Publish, then Channels → Microsoft 365 and Microsoft Teams, keep Make agent available in Microsoft Copilot selected and choose Add channel. See agent in Teams installs it for you; in Microsoft 365 Copilot, type @ and pick the agent.

Prefer per-user sign-in? Choose OAuth 2.0 → Dynamic discovery instead of an API key: each user then signs in to AnythingMCP the first time the agent calls it.

Self-hosting? Use your instance's public HTTPS address instead of https://cloud.anythingmcp.com. Copilot Studio connects from Microsoft's cloud, so localhost does not work.

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 Copilot 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.

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 Copilot uses a tool, AnythingMCP fetches the content and passes it to Copilot, and the call is recorded in your workspace's audit log. AnythingMCP Cloud is hosted in Frankfurt, Germany.

Which Copilot is this for? Microsoft 365 Copilot at work, through agents built in Copilot Studio. The Microsoft Copilot app for personal accounts has no option to add your own MCP server.

What do I need? A work account with access to Copilot Studio (a license or a trial) to build the agent. People who use it in Microsoft 365 Copilot or Teams need access to the agent: share it with them, or ask an admin to publish it to the organization. If your organization applies data policies to Power Platform connectors, they cover MCP servers too.

The agent doesn't call the tools. Check that the header name is exactly X-API-Key and that the key belongs to the same MCP server as the URL, and make the server description specific: Copilot Studio uses it to decide when to call the server. Publish the agent again after each change; in an open chat, type "start over" to get the new version.

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