The user has passed (or will pass) a markdown file of raw material. This is exploit: the exploring is done, the pile is fixed — commit to a path through it and mine the pile to fill each beat.

If the user did not say where to save the article, ask once and remember the path.

Then run a beat-by-beat journey, choose-your-own-adventure style:

Establish the prerequisites. Before any beats, settle with the user what the audience already knows walking in — the concepts that are grounded from the start. Everything else must be grounded by a beat before a later beat can use it. See Grounding.
Write 2–3 candidate starting beats, drawn from the raw material. Each is a different entry point into the article. Each may only lean on grounded concepts; note what new concepts each one grounds. Show the user the beats before writing to the article file. The user picks one. Preview what beats that pick unlocks — as if the user is seeing a little way down the path.
Once the user picks a starting beat, write only that beat to the article file. A beat may be one sentence or several paragraphs — whatever that beat naturally is. Stop there.
Re-read the article file from disk. Then offer 2–3 candidate next beats — different directions the journey could pivot to from where the article now stands. Each must be reachable from the current grounded set; note what each one grounds.
Loop steps 3–5 until the article reaches a natural end.

writing-beats

Grounding