Server Configuration
Describes the environment variables required to run the server.
| Name | Required | Description | Default |
|---|---|---|---|
| SUBSTACK_USER_ID | Yes | Your Substack User ID | |
| SUBSTACK_SESSION_TOKEN | Yes | Your Substack session token (the value of the connect.sid cookie, usually starting with s%3A) | |
| SUBSTACK_PUBLICATION_URL | Yes | Your Substack URL, including custom domain if you have one (e.g., https://newsletter.yourdomain.com or https://yourblog.substack.com) |
Capabilities
Features and capabilities supported by this server
| Capability | Details |
|---|---|
| tools | {
"listChanged": true
} |
Tools
Functions exposed to the LLM to take actions
| Name | Description |
|---|---|
| get_subscriber_count | Get the current subscriber count for your Substack publication |
| list_published_posts | List published posts with pagination. Returns title, date, slug, and URL for each post. |
| list_drafts | List draft posts. Returns title, creation date, and audience for each draft. |
| get_post | Get the full content of a published post by ID. Returns title, body HTML, metadata. |
| get_draft | Get the full content of a draft post by ID. Returns title, body, metadata. |
| get_post_comments | Get comments on a published post. Returns commenter name, comment body, date, and reaction counts. |
| create_draft | Create a new draft post. Accepts markdown body which is converted to Substack's format. Does NOT publish — creates a draft only. |
| update_draft | Update an existing draft post. Only works on unpublished drafts. Accepts markdown body. |
| upload_image | Upload a base64-encoded image to Substack's CDN. Returns the hosted image URL. |
| create_note | Create a Substack Note (short-form content). Accepts markdown text. Publishes immediately — there is no draft state for notes. |
| create_note_with_link | Create a Substack Note with a link attachment. The link is displayed as a rich card below the note text. Publishes immediately. |
Prompts
Interactive templates invoked by user choice
| Name | Description |
|---|---|
No prompts | |
Resources
Contextual data attached and managed by the client
| Name | Description |
|---|---|
No resources | |