Overview
The atom is the unit a vault compounds on. An atomic note holds exactly one idea, states it in the title, cites its source, and explains its links. Atoms are cheap to recombine into a brief, an essay, or an argument; long mixed-topic notes are not. Every rule below exists to keep a note recombinable. The folder these live in is set in vault-architecture.
Split any note whose title needs an “and”
The conjunction test is mechanical and it catches most violations. If the natural title is “MECE decomposition and when it fails,” you have two atoms. If the body carries two claims that could be disagreed with separately, you have two atoms.
Word count is the weaker signal, but it is the one a machine can check. Past roughly 500 words a note is usually carrying a second idea. Treat the count as a prompt to reread, not as proof: a 200-word note can still hold two claims, and only a reading catches that. semantic-audit covers the judgment pass that finds the seam.
Write the title as a claim, not a topic
The title is the note’s assertion, written as a full sentence or a specific noun phrase that reads naturally inline in prose.
Good: luhmann-produced-70-books-across-30-years-using-his-zettelkasten.md
Bad: luhmann-zettelkasten.md
Good: compound-interest-doubles-money-faster-than-linear-saving.md
Bad: compound-interest.md
A topic title is a folder pretending to be a note. It invites appending, and an appended note grows until it stops being atomic. A claim title has no room to grow: new material either supports the claim, contradicts it (write a contradiction note), or belongs to a different claim (write a new atom).
Filenames are kebab-case slugs, the unique id lives in frontmatter, and the human-readable form lives in title. The naming rationale is the same one in naming-conventions.
Keep the body between 100 and 500 words
The body states the claim, gives the reasoning, and stops. Two to five sentences in your own words is a healthy default for an atom mined from a source, with the supporting quote left in the source note rather than copied across.
Write in your own phrasing, not the source’s. A paraphrase forces comprehension; a copied passage records only that you saw the text. If a note is a copied passage, it belongs in 10-Sources/ as evidence, not in 20-Atoms/ as a claim.
Cut filler that would be true of any note. Hedged summary prose is the tell of an atom with no load-bearing content, and it is what a semantic audit flags as vapid. The banned constructions in anti-slop apply to vault prose as much as to published prose.
Give every atom a status and promote it deliberately
Three states, one per note, carried as a tag:
#status/seedling: captured, not yet defended.#status/budding: sources attached, links explained, would survive a challenge.#status/evergreen: battle-tested, you would defend it in writing.
Promotion happens in the weekly review, never at creation. The promotion question is one sentence: would I defend this in writing? A seedling still unpromoted after 30 days is either an idea you do not actually hold or one you have not done the work on, and both resolve to promote or delete. See vault-maintenance for the review that runs this.
Give every atom three to seven explained outbound links
Fewer than three outbound links means the atom is drifting toward orphanhood and will never surface when it is relevant. More than seven usually means the note is a hub, which means it is not atomic.
Every link gets a sentence saying why it is there. A trailing list of bare wikilinks records adjacency without recording the relationship, and both the deterministic and the semantic audits flag that pattern. The full policy is in linking-and-tags, and the sourcing requirement that pairs with it is in source-verification.