13 articles in 2 weeks
Most people treat Substack as a manual publishing platform. Log in, paste text, click publish, done. This guide replaces that entire flow with an automated pipeline driven by your AI agent. The result: 13 articles published on sedim3nt.substack.com in two weeks, with cross-posting to Facebook, X, and Bluesky triggered automatically on every publish.
The foundation is the SID cookie authentication method. Substack doesn't have an official public API, but it does have an internal one — the same one the web app uses. You authenticate with your SID session cookie and hit the draft endpoint directly. This guide includes the exact JSON payload format for creating drafts, the byline configuration for multi-author setups, and the publishing workflow that takes a draft from created to live.
Draft creation is where the agent does its best work. You define a content brief — topic, target length, tone, key points — and the agent generates, formats, and submits the draft. The article template ensures consistent structure: compelling headline, strong lede, three-to-five sections with headers, a concrete takeaway at the end. Every draft lands in your Substack dashboard review queue before publishing. You stay in control; the agent does the legwork.
The cross-posting workflow is what makes the math work. One article becomes four distribution events: Substack native, Facebook (article URL + two-sentence summary), X (hook thread format with cover image), and Bluesky (tight 300-character excerpt with link). The guide includes the scripts and prompts for each platform format. A single publish triggers all four.
The editorial calendar template is a markdown file your agent updates weekly — upcoming topics, drafts in progress, scheduled publishes, and performance notes from the previous week. Cover image generation hooks into the image generation workflow if you have it set up. Newsletter growth tips section covers what actually moves subscriber counts vs. what most guides focus on. Analytics tracking pulls open rates and subscriber data into your daily memory log.
Initial release. Built from 13-article production run on sedim3nt.substack.com. Full cross-posting automation, SID auth, editorial calendar template.