The ACE Framework in Obsidian: Atlas, Calendar, Efforts

ACE is a three-folder structure for Obsidian vaults, built by Nick Milo of Linking Your Thinking as the successor to his earlier LYT structures. It stands for Atlas, Calendar, Efforts — one folder for the maps that explain how your vault fits together, one for anything tied to a date, and one for active work with an end state. Everything else lives underneath those three, usually on top of PARA. The reason ACE beats a topic tree — Marketing/, Health/, Ideas/, and forty more categories you invented on day one — is that a topic tree asks you to guess a note’s subject before you’ve written it. ACE asks a smaller question: is this a map, a moment in time, or a piece of active work? Three buckets, decided in seconds, instead of a folder tree you re-organize every few months because your topics keep changing and your notes never fit where you filed them.

I’m a former Senior Mentor in Building a Second Brain, and I run ACE on top of PARA in the same vault that runs this business — not a demo folder built for a screenshot. What’s below is the actual structure, with the parts that need to stay private described but not shown. If you’re earlier in the process — you don’t have a vault yet, or yours is one flat pile of notes — start with the PKM guide before you touch folder structure at all.

The Comparison

ACE vs. PARA vs. LYT/ACCESS: What’s the Difference?

These three get confused for each other constantly, and they’re solving different problems. PARA organizes by actionability. ACE organizes by kind of thing — knowledge, time, action — which is a layer above actionability, not a replacement for it. LYT’s earlier structure, sometimes shortened to ACCESS, was Milo’s first pass at the same idea before he simplified it down to three folders.

They stack. PARA still handles what’s actionable — a project with a deadline, an ongoing area of responsibility, reference material, done work. ACE sits above that and answers a different question: where do the notes that explain your system live, separate from the notes that are your system’s actual output? Milo’s own framing for this, from the Linking Your Thinking course, is three headspaces — Knowledge, Time, and Action — and Atlas, Calendar, and Efforts are just those three headspaces given a folder each.

A topic tree asks you to categorize before you've thought. ACE asks you to place, which takes a second, and lets the thinking happen inside the note instead of at the filing cabinet.

The Real Vault

Inside My Actual Vault: ACE Running on Top of PARA

Here’s the top level of the vault this business runs on. Some subfolders below Areas and Projects are described, not shown — client work and personal records stay private, structure only.

~/Projects/
├── Atlas/            → the maps: MAP.md, AI-GUIDE.md, WORKFLOW.md, plans, rules
├── Calendar/         → daily notes, weekly reviews, meeting logs
├── X/                → the system itself: scripts, workspace configs
├── 01-Projects/      → Efforts — active work with an end state
├── 02-Areas/         → ongoing responsibilities (PARA)
├── 03-Resources/     → reference material, tools, reusable assets (PARA)
└── 04-Archive/       → done and inactive (PARA)

Atlas is the map layer, not a notes dump. It holds MAP.md — the front door, the file that lists every hub in the vault and where each one lives — plus an AI-GUIDE.md written specifically for agents opening the vault cold, and a WORKFLOW.md that’s the daily operating guide. Nothing in Atlas is raw content. If a file in Atlas isn’t a map, a plan, or a rule that explains the system, it’s in the wrong folder.

Calendar is everything tied to a date and nothing else. Daily notes, weekly reviews, the running log of what happened this week. It’s the one folder in the whole vault where chronology is the organizing principle instead of topic or project.

Efforts — the PARA “Projects” folder, renamed and numbered 01-Projects so it sorts first — is anything with a deadline and a finish line. A SaaS build, a job-search campaign, a habit-tracking app: each gets its own folder, and each folder eventually closes. The renumbered PARA folders sit underneath: 02-Areas for ongoing responsibilities that never finish (a client relationship, a brand), 03-Resources for reference material and tools, 04-Archive for anything done — archived, never deleted, so nothing that once mattered actually disappears.

The part that matters most if you’re running any AI agent against this vault: Atlas is the front door. Claude Code opens a vault folder cold, the same way it opens a code repository, and it has no idea what’s current and what’s dead weight until it reads something that tells it. MAP.md is that something. One file, read first, that says “here’s every hub, here’s what’s active, here’s where to look.” Without it, an agent guesses from whatever notes happen to be nearby — recent files, obvious folder names — and guesses wrong constantly, because “recent” and “important” aren’t the same thing in a vault that’s been running for years. With it, orientation drops from five minutes of exploring to five seconds of reading one file.

Read Atlas/MAP.md first. Then tell me: which Efforts folder have I touched most recently, and what's the single next step on it according to my last few daily notes in Calendar/?

The Setup

Set Up ACE in Obsidian in 20 Minutes

You’re not migrating anything on day one. You’re adding three folders and one map file — the rest moves in gradually, as you touch it.

1. 01
   Create the three folders. `Atlas/`, `Calendar/`, and rename or create your active-work folder as `Efforts/` (or number it `01-Projects/` if you're stacking on PARA). Nothing else changes yet.
2. 02
   Move your active projects into Efforts. Anything with a deadline and a finish line. If you're not running PARA underneath yet, everything else can stay where it is for now — Areas, Resources, and Archive can wait for a second pass.
3. 03
   Write MAP.md. One file at the root of Atlas, or the root of the vault. List every major folder, one line each: what it holds, why it exists. This is the file a fresh Claude Code session — or a fresh version of you, six months from now — reads first. Keep it short enough to actually maintain.
4. 04
   Make a daily-note template. Obsidian's core Daily Notes plugin (built in, no install needed) or the Templater community plugin both work. Three or four lines is enough to start: what happened, what moved, what's next. This is what Calendar is for.
5. 05
   Build one map of content. Pick your busiest Effort or Area and write a single note that links out to everything related to it — no new content, just links and a sentence of context each. That's your first real Atlas file, and it's the pattern for every one after it.

Twenty minutes gets you the skeleton. The rest — moving old notes, writing more maps, tightening the daily template — happens as friction shows up, not before.

In Practice

The Daily and Weekly Workflow Through ACE

Daily, Calendar does the work. Open today’s note, capture whatever came in — a thought, a link, a half-finished idea — without deciding where it belongs yet. If you’re running an AI agent in the vault, this is the moment to ask it to fold any loose captures into the day’s note, one line each, no editing. Organizing happens later. Capture doesn’t wait for a decision.

Weekly, the review runs across Efforts and Calendar together: what moved in active projects this week, and what showed up in the daily notes that hasn’t been filed yet. Anything that’s actually a map — a recurring theme, a system you keep explaining the same way — gets promoted into Atlas as its own file. Anything that’s finished moves out of Efforts and into Archive. The review is short because the folders are already sorted by kind of thing; you’re not searching a topic tree hoping something jumps out.

Monthly or whenever it’s needed, Atlas gets a pass on its own: is MAP.md still accurate, does every hub in it still exist, is there a map that’s gone stale because the thing it described changed. Atlas is the one folder that has to stay honest, because everything else — your own orientation, an agent’s orientation — depends on it being current.

What Goes Wrong

Mistakes That Break an ACE Vault

Over-nesting Atlas. A map folder with its own subfolders, tags, and cross-references defeats the point. Atlas should be flat enough that “what’s in here” is answerable by looking, not searching. If Atlas needs its own map to navigate, something’s wrong.

Treating Atlas as a dump. The first thing that goes wrong is a random note landing in Atlas because you weren’t sure where else to put it. Atlas holds maps and rules — documents about the system — not the system’s actual content. If a file could just as easily sit in an Effort or an Area, it doesn’t belong in Atlas.

No archive discipline. Efforts that finished but never got moved to Archive pile up, and six months later Efforts is half active work and half done work, which defeats the reason it exists — a folder you can trust to mean “this still needs attention.” Archive isn’t a place things go to be forgotten. It’s a place things go so Efforts stays honest.

Skipping the map file. Building the three folders without writing MAP.md gets you ACE in name only. The folders sort your notes; the map is what makes the sort legible to you — or to an agent — six months later when you’ve forgotten why something’s filed where it is.

Copying someone else’s Atlas. The folder names are Milo’s. What goes inside them is yours. A map file that describes someone else’s business, someone else’s projects, structured the way a course template suggested, doesn’t orient anyone. Write the map for the vault you actually have.

FAQ

What is the ACE framework in Obsidian?

ACE is a three-folder vault structure — Atlas, Calendar, Efforts — created by Nick Milo of Linking Your Thinking. Atlas holds maps of content and system-level notes, Calendar holds anything tied to a date, and Efforts holds active work with an end state. It maps to three headspaces Milo teaches directly: Knowledge, Time, and Action.

ACE vs PARA — which should I use?

They’re not mutually exclusive. PARA (Projects, Areas, Resources, Archive) organizes by actionability — what needs doing soon versus what’s ongoing versus what’s reference. ACE organizes by kind of thing — is this a map, a date, or active work. Most vaults that use both run ACE on top: Efforts becomes the renamed PARA “Projects” folder, and Areas, Resources, and Archive sit underneath it unchanged. Use PARA alone if you want the simplest possible start. Add Atlas once you notice you’re re-explaining your own system to yourself, or to an AI agent, every few weeks.

Who created the ACE method?

Nick Milo, through his Linking Your Thinking course and the Obsidian community. ACE is the simplified successor to his earlier LYT vault structures. PARA — the Projects/Areas/Resources/Archive method ACE is commonly layered on top of — is a separate framework created by Tiago Forte through Building a Second Brain. The two are frequently combined but were built independently.

Do I need plugins for ACE?

No. ACE is a folder structure, and folders are native to every notes app, Obsidian included. A daily-note template helps for Calendar — Obsidian’s built-in Daily Notes plugin covers it, or the community Templater plugin for more control — but nothing about Atlas, Calendar, or Efforts depends on a plugin existing.

Can I use ACE with Claude Code?

Yes, and it’s a strong pairing. An agent opening a vault cold has to figure out what’s current before it can help — ACE’s Atlas folder, with one MAP.md file at the front, is exactly the orientation an agent needs. Point Claude Code at Atlas first in your CLAUDE.md and every session starts oriented instead of guessing from whatever files happen to be recent. The full setup for connecting an agent to a vault at all is in the agentic PKM guide.