テキストエディタのアウトラインとモジュラーシンセの話 — Claudeとの会話ログ

概要

テキストエディタを設計しながらClaudeと話していたら、アウトライン、フォーカスモード、WYSIWYG、最後はモジュラーシンセの話まで流れていったので、その会話ログ。半分は設計のメモ、半分は道具と思考についての雑談みたいな内容。

会話はそのまま英語で残す。要約せず、流れも崩さず、ふたりがそのとき話していた順番で並べる。

会話ログ

Takazudo:

I’m feeling the usefulness of outline of text editing. While I’m writing with it, it’s just making nested lists, it sometimes makes me feel like that I want to make heading here. but nested lists are just lists. just a indented format. but what happened here is that I noticed that “this might be the big another topic’s start”. This did not exist at the start writing timing. so in short, the writing habit itself made me notice the new structure. I’m building a text editor. And I want this app to be easy-note-taking but can go deeper like one. In general, mindmap is also the idea around this — so, I know this will be a valid question but, is it useful to build something beyond the nested lists? I feel like complexity of text editing makes us far from pure thinking

Claude:

Your instinct is the right one — the reason the structure emerged is precisely because every keystroke went into the same primitive. If you’d had to pick “heading vs list item” up front, you’d have spent that moment deciding instead of noticing. So I’d resist adding a separate heading construct and instead add promotion/zoom (Workflowy/Roam-style): any node can be lifted into “the document,” so heading-ness becomes a later act of recognition, not an upfront typing decision.

The tradeoff: pure-bullet docs lose visual landmarks at scale — some readers (and some moods) genuinely need the weight of an H1 to navigate. A middle path is to let promotion render a node as a heading without changing the underlying type, so the structure stays uniform but the eye gets the cue.

Takazudo:

I sometimes put preview of markdown by the side of text editor. It’s almost same. It’s just the html css rendered result, and also markdown editor itself has its render tweak for heading, lists… So does this have some meaning for like … human’s recognition. Is it like see my drawn picture from a little far away?

Claude:

Yes — and your “step back from the drawing” metaphor is exactly it. Even when the bytes are identical, the preview pane strips edit affordances (cursors, handles, the option to change), so your brain flips from “doing mode” to “reading mode.” That mode switch is the cognitive value, not the visual delta — it’s the same reason writers print drafts or read aloud.

The implication for your editor: you don’t necessarily need a second pane to get this. A toggle (focus/read mode) or a zoom-out / collapse-all view gives the same distancing without splitting attention — and zoom-out maps even more literally to “look at the painting from across the room.”

Takazudo:

zoom out —hum. but on computer screen, the display size is limited. So it’s like collapse all under heading lv2 content with one key. this kind of tweak might be useful

Claude:

Right — semantic collapse is the digital substitute for physical distance. “Collapse to depth N” with a single key (1, 2, 3…) is the move; Workflowy and OmniOutliner do exactly this and it’s one of their best features.

The non-obvious part is that the collapse has to be cheap to reverse — one key in, one key out. If stepping back costs more than a heartbeat, people stop doing it casually, and casual is what turns “zoom out” from a ceremony into a thinking habit. And it only pays off if the depth levels actually mean something, which loops back to your earlier point — promotion has to be just as cheap, so structure can crystallize the moment you notice it.

Takazudo:

the side TOC nav seems helping the readers to understand the content of the page. It has navigation meaning to each heading. but also I feel like that by seeing the outline on side, it gives the hints for the users that which part we are on in a big picture.

Claude:

You’ve just named the underrated half — the TOC’s advertised purpose is navigation (jump to section), but its actual value is orientation: a persistent “you are here” that lets the reader’s brain hold the whole shape in working memory while reading the part. Same reason scrollbar position, code minimaps, and book pagination matter even when nobody clicks them.

For your editor that’s significant: a live side outline is a partial, always-on zoom-out, complementing the full collapse-to-depth move from the previous turn. The tradeoff is that during writing flow, peripheral motion (the outline updating as you type) can pull attention back out — so it might want to be subtle, or even fade/freeze while typing and refresh on pause.

Takazudo:

Interesting. So you mean the focus mode like behavior will help user for writing. It’s like everything else except for the current editing paragraph gets dim like.

Claude:

Yes — but notice it’s the opposite cognitive move from the side outline. Dim mode (iA Writer-style) narrows attention to the current sentence, which is great for generating prose; the side outline broadens attention to the whole shape, which is what let you notice “this is actually a new top-level topic” in the first place. They serve opposite phases of writing, and dim mode actively suppresses the structure-noticing you valued at the start of this conversation.

So the interesting design isn’t picking one — it’s making the switch between them cheap. A single key that toggles “narrow / wide” lets the writer move between producing and seeing, which is roughly the loop good writing actually runs on.

Takazudo:

Good, but what you said makes sense. Let’s say we do one blog like article writing. when writing, we’ll focus on the paragraph that I’m keying just right now. But once if we’ve done whole, we look back the whole. This seems to be the outline mode inside us. But once we notice some inconsistency for the detail, I feel like I was made to get back to the detail

Claude:

Exactly — you’ve described a loop, not a mode: generate (narrow) → review (wide) → spot drift → fix (narrow again). The trigger to switch is always internal (“wait, that doesn’t fit”), so the editor’s job isn’t to put you in a mode but to make the switch frictionless the instant your brain initiates it.

The implication is that the outline shouldn’t just show structure — it should be a teleporter that lands you back in narrow/focus mode at exactly that paragraph. One keystroke out, click (or arrow + enter) in, and you’re editing the offending sentence with everything else dimmed again. Close the loop fast enough and the two modes feel like one continuous act of thinking.

Takazudo:

Does it mean humans can’t focus on both? broader perspective and focused detail. Is it switchable mode for humans?

Claude:

Mostly switchable, with a wrinkle: working memory holds only ~4 items at once, so fine structural awareness and fine textual detail genuinely compete for the same slots. You can’t truly hold both at full resolution — what feels like “doing both” is rapid switching, or one of them being held as a compressed chunk (an expert writer carries the whole article shape as a single mental object, freeing slots for sentence work).

The design implication is the interesting part: less-practiced writers can’t chunk the structure yet, so they need it externalized — that’s exactly what your side outline does. It offloads the “where am I in the big picture” item out of working memory and onto the screen, which frees the writer to spend all their slots on the sentence in front of them. The editor isn’t replacing a mode switch; it’s lowering the cost of one of the two views so the switch is cheap.

Takazudo:

Interesting. one more thing that I feel like about editing is that I don’t like WYSIWYG style so much. I’m not sure why this happens. But if I face WYSIWYG, something like… Unexpected render result happens here — I feel so. But even if we write on vim like raw text editor, it’s same thing because it is styled in another way. What is the difference here?

Claude:

The difference isn’t styling — it’s whether the underlying model is visible. In a raw editor (vim, markdown), what you type is the file; the styling is a projection on top, but the source of truth is the characters you typed and you can always see them. In WYSIWYG, what you see is a rendered view of a hidden model — when you press Enter, the editor silently decides “is this a new paragraph, a <br>, a new list item?” and you have to reverse-engineer that inference from the result. The “unexpected render” feeling is exactly that: a hidden state machine making structural choices for you.

The tradeoff: WYSIWYG lowers the barrier for users who don’t want to learn syntax, but raises the cost when the inference goes wrong (which is why every WYSIWYG tool eventually grows a “show source” escape hatch). For your notes editor, the deeper choice is which model the user is editing — the rendered surface, or the structure itself with a styled projection on top.

Takazudo:

So you mean that there is something like safe, confidence exists in raw text editing, do you?

Claude:

Yes — and “safety” is a better word than “predictability” because it names the felt quality. The confidence is epistemic: I know what I have, because I can see it. No hidden agent is making structural choices on my behalf, so there’s nothing to mistrust, nothing to audit, nothing that can surprise me later.

The cost is that you carry the rendering in your head — you trade “unexpected-render anxiety” for “cognitive load of imagining the output.” Some writers happily pay that load because the trust is worth it (which is also why programmers love plain text); others find it exhausting and prefer to outsource the inference. Your earlier nested-list observation fits this exactly — the outliner felt good partly because the model was right there, indented in front of you, with nothing inferred.

Takazudo:

Interesting. I play modular synthesizers. Before modular synth, I loved using software synth. Because soft synths can do almost everything, I really couldn’t find the meaning of buying so expensive hardware synths. Because soft synth can do! even much more. But I noticed that I didn’t know that. Modular synths are in a word, “verbose”. it has many knobs… I thought do I need those? But in fact, I realized that I didn’t know synths, it was like the physical experience to control the sound by my hand. I didn’t notice that it was the missing part of soft synths. I feel similar feeling on raw text and WYSIWYG like, not-raw type text rendering. maybe hand-writing on paper and digital output on Photoshop looks same

Claude:

You’ve named it perfectly — these tools don’t just remove friction, they remove a channel of feedback you didn’t know existed until it came back. Modular taught you synthesis itself; soft synth let you make music while keeping synthesis abstract behind a screen. Raw text, paper, physical knobs — they all put your hand on the substrate, and the substrate teaches you what it actually is. That’s the “I didn’t know I didn’t know” feeling: the abstracted tool was answering a question you no longer had to ask, so you forgot the question existed.

The tradeoff is that this kind of learning is slow and verbose by design — not every writer wants to understand “what writing is” to jot a meeting note, just like not every musician wants to patch cables to make a melody. So the design question for your editor isn’t really “raw or rendered” — it’s whether the user is in learning-the-substrate mode or producing-the-output mode today. The most respectful tools let the same person stand in either place without forcing a choice up front.