I Built an AI Writing Tool That Doesn't Write For You
There's a version of AI writing tools that takes your blank document and fills it. You describe what you want, the AI writes it, you read it, maybe tweak it, publish it. Fast. Efficient. Not yours.
I didn't want to build that. And I didn't want to use it, either.
Draft Desk is what I built instead — an AI writing companion that reads along while you write. It doesn't generate your content. It doesn't rewrite your sentences without asking. It watches, listens, and helps the way a really good editor would: quietly, specifically, and only when it matters.
This is the full story of what it is, how it works, who it's for, and how it got to where it is today.
What Draft Desk Is
Draft Desk is a browser-based writing app that pairs a clean, distraction-free editor with an AI companion that observes your writing in real time.
You write. The companion reads along. It catches grammar issues silently. It checks whether your tone matches the one you're going for. It offers ideas when you've written enough for context. It never takes over. The words on the page are always yours.
It lives at draftdesk.cloud and works entirely in your browser — no download, no account required, no data leaving your device. On iOS and Android, you can save it to your home screen and it behaves like a native app.
The AI features run on your own Anthropic API key — meaning you pay only for what you use, your writing never touches my servers, and the tool works even if I disappear tomorrow. But here's the part I'm most proud of: 18 of Draft Desk's features require no API key at all. The app is a complete writing tool before you ever connect AI to it.
What It Does
The Writing Environment
The editor is a full-featured rich text workspace. Bold, italic, underline, strikethrough. Three heading levels. Blockquotes, bullet lists, numbered lists, dividers. Undo and redo. A format toolbar that stays out of the way until you need it.
You can store up to 10 named documents, all saved locally in your browser. Switch between them without losing anything. Every document autosaves every five minutes and keeps a full version history — up to 20 snapshots, each restorable in one click.
Export to plain text, Markdown, Word (.docx), or PDF. Smart Copy strips formatting symbols before copying to your clipboard. Smart Share uses your device's native share sheet on iOS and Android — or falls back to a clean options panel on desktop.
The font, size, and line spacing are all adjustable. You can write in Playfair Display (the default serif), or switch to something that suits you. Typewriter mode keeps your active line centered on screen. Dark and light mode both look considered — not like someone flipped a toggle and called it done.
Focus Tools
Focus Mode hides everything except the text. No panels, no toolbar, no distractions. Press F or click the button to enter, same to exit.
Sentence Focus dims every sentence in your document except the one your cursor is in. The rest of the text fades to 12% opacity. Your active sentence stays at full brightness. It's the iA Writer focus experience — built to make you edit one thought at a time.
Paragraph Focus does the same thing at the paragraph level. Less precise, better for longer-form work where you need a bit more context around what you're editing.
Quality Tools (No API Needed)
Readability Score calculates your Flesch-Kincaid grade level, reading ease, average sentence length, passive voice count, and adverb density — all in your browser, instantly, with no API call. It updates as you type.
Writing Sounds adds typewriter click sounds as you type, plus optional ambient audio — rain, coffee shop, fireplace, white noise, or forest. All generated procedurally using the Web Audio API. No audio files, no network requests. Just atmosphere.
Find & Replace opens with ⌘F. Navigate matches with arrow buttons, replace one instance or all at once. Full regular expression support for the power users.
Read Aloud uses your device's built-in speech synthesis to read your writing back to you. Catching errors by ear is different from catching them by eye.
Writing Streaks tracks your daily writing habit. Session timers, word goals, progress bars. The kind of accountability that's annoying to ignore.
Writing History Heatmap shows a 91-day GitHub-style calendar grid in the Stats panel — which days you wrote, how many words, how your output changes across weeks and months.
Smart Templates give you eight starting points: Blank, Journal (auto-dated), Essay, Email, YouTube Script, Cover Letter, Story, and Tweet Thread. Each one pre-sets the right tone in the AI companion if you have a key connected.
Manual Notes is a private notepad inside the Editor Notes panel — a "My Notes" tab where you can jot down plot ideas, reminders, or research notes about your draft. Offline, no AI, just yours.
AI Features (With Your Anthropic Key)
This is where Draft Desk gets genuinely useful for writers who want feedback, not ghostwriting.
Live Grammar Correction fixes spelling and punctuation as you type. It fires in the background after a three-second pause. You'll see errors corrected in the companion log — never in your text without your knowledge.
Tone & Vibe Analysis lets you set a target tone — Warm, Confident, Formal, Conversational, Serious, Playful, or anything you describe in your own words. Every two and a half minutes, the companion checks your recent writing against that tone and logs what it finds.
Contextual Suggestions generates ideas grounded specifically in what you've written. Every suggestion references a real passage. They appear after meaningful progress — at least 150 new characters since the last check, with a two-minute cooldown. You'll never get a suggestion that could have been written by someone who hadn't read your draft.
Transform reformats your writing into something else entirely: email, article, YouTube script, tweet thread, APA paper, cover letter, and more. You choose whether the AI can add new content or only reformat what's already there.
Writing Companion is the persistent AI presence that ties it all together — a running log of observations, grammar notes, tone checks, and ideas. It logs everything with context. It notices patterns. It doesn't repeat itself.
Character & Place Tracker scans your writing for names, locations, and recurring elements. Keeps your fictional world consistent without you having to maintain a separate spreadsheet.
Writer's Block Prompts generates contextual prompts when you're stuck — not generic "what happens next?" suggestions, but prompts built from your actual characters, setting, and recent pages.
Writing Intent lets you tell the companion what you want the reader to feel or do after reading — "take action," "feel moved," "trust me." It then checks whether your writing is actually achieving that goal.
What It Doesn't Do
This is as important as the feature list.
Draft Desk does not write your content for you. There's no "generate" button, no auto-complete, no draft-from-prompt feature. If you want the AI to write something, you'll need a different tool.
It does not store your writing on any server. Everything lives in your browser's localStorage. Your words never leave your device unless you export them yourself or send them to the Anthropic API for processing.
It does not train on your writing. The API calls are stateless — they read a slice of your recent text, respond, and forget. Nothing is stored or learned between sessions.
It does not require an account. No login, no email, no subscription for the core product.
It does not serve ads. Draft Desk is ad-free.
It does not use a shared AI pool that someone else controls. Your API key, your usage, your costs. Typical usage — an hour of focused writing with all AI features active — runs well under $0.05 in API costs.
Why I Built It
I create content. I write video scripts, essays, and long-form notes constantly — for YouTube, for work, for myself. And over the past couple of years I've watched AI writing tools follow the same pattern: build something that generates text, market it as a writing tool, and quietly reframe what "writing" means.
I wasn't interested in that. The things that make my writing mine — the rhythm, the specific word choices, the way I structure an argument — are exactly what those tools flatten out. After enough frustrating sessions with tools that kept trying to finish my sentences, I decided to build the thing I actually wanted.
The constraint I set for myself early on: the companion observes, it never takes over. It can tell me a sentence is passive. It can ask if the tone matches what I was going for. It can suggest an idea and wait. But it doesn't act without my input. The writing stays mine from first word to last.
There was also a practical element. As someone who thinks about IT and systems professionally, the BYOK (bring your own key) model made sense to me. Centralized managed-API writing tools are expensive, fragile, and opaque. I wanted something I could understand completely, cost-control precisely, and trust fully.
Who It's For
Draft Desk works best for people who already know what they want to write and want help making it better — not people who want the AI to figure out what to say.
Content creators who write scripts, essays, or newsletters and want a workspace that keeps them in the flow without interrupting them every other sentence.
Professionals writing emails, proposals, cover letters, or reports who need a tone check and grammar pass without sending their documents to a third-party server.
Students and academics working on essays or long-form assignments who want readability feedback and structural suggestions without outsourcing the thinking.
Fiction writers who want a companion that tracks their characters and places and catches inconsistencies — without trying to write the story for them.
Anyone who types a lot and wants an environment that feels considered. The writing sounds, the focus modes, the heatmap — these aren't gimmicks. They're there because the experience of writing matters, and most apps treat it like a form to fill out.
And because 18 features work with zero AI setup, the tool is genuinely useful to anyone who just wants a clean, offline-capable writing environment and doesn't care about AI at all.
How I Built It
Draft Desk is a single HTML file.
That's not a simplification — it's literally one file. The entire application: 10,000+ lines of HTML, CSS, and JavaScript, deployed to Cloudflare Pages with a custom domain. No build step, no Node server, no npm install, no framework. Open the file, it works.
The AI layer runs entirely in the browser via direct fetch calls to the Anthropic API. The key is held in browser memory only — it's never sent to any server I control. All API calls use the claude-sonnet-4-6 model, with max_tokens calibrated per task: 60 for tone analysis, 800 for grammar, 600 for suggestions, 4096 for transform. These aren't arbitrary — they're tuned to prevent runaway costs while leaving room for quality responses.
The writing sounds are generated procedurally with the Web Audio API — different noise-shaping algorithms for rain, café, fire, white noise, and forest. No audio files. The sentence and paragraph focus overlays use a transparent-textarea approach: when focus mode is active, the textarea text becomes color: transparent, and a precisely positioned overlay div renders the same text with dim/bright spans that follow the cursor. This avoids the font-misalignment and flashing issues that come from trying to fake it with absolutely-positioned elements that don't match the textarea's layout.
Version history, documents, notes, preferences, and writing history are all localStorage. The app is fully functional offline once loaded. It can be installed as a PWA on any device and works identically to the web version.
I worked on this iteratively alongside an AI assistant — which is, appropriately, one of the more honest ways to build an AI writing companion. A lot of the architectural decisions came out of that back-and-forth: where to put state, how to sequence renders, when a debounce is the right answer versus a cooldown timer.
Design Choices
The aesthetic was a deliberate reaction to everything I found cold and clinical about writing apps.
The color palette centers on #171411 — a very dark warm brown, not pure black — paired with #ece6dc, which is closer to aged paper than white. The accent is a terracotta red (#e07055) and a muted gold (#d4a84c). The overall effect is supposed to feel like a well-worn writing desk: warm, textured, serious without being sterile.
The two fonts are Playfair Display for headings and the wordmark — a high-contrast editorial serif that signals craft without being precious — and IBM Plex Mono for UI elements. Mono for interface text is a choice I'd make again: it creates a visual distinction between the tool and the writing without requiring a third font.
The companion log is intentional about its format. Notes appear with a timestamp, a type indicator, and specific content — never vague, never just "good job." The idea is that the log should feel like margin notes from a thoughtful editor, not status updates from a bot.
On mobile, the app uses a bottom dock (Menu / Notes / Assist / Goal) instead of trying to cram the desktop toolbar onto a small screen. The assist panel slides up as a bottom sheet rather than dropping down inline — which kept the entire screen from being taken over by a settings panel every time a user wanted to toggle one thing.
Pills for AI features start muted and locked when no API key is present. They're visible — because the features exist and are worth knowing about — but clearly inactive. A single tap on a locked pill logs a friendly companion message pointing toward setup. No error, no modal, no pressure.
How to Use It
Go to draftdesk.cloud. On the landing page, click "Open Draft Desk" or navigate directly to draftdesk.cloud/app.
On first load, you'll see a setup screen. If you have an Anthropic API key, paste it in and click Confirm — Draft Desk validates it with a minimal test call, then launches. If you don't have one, click "Skip for now" and you'll get the full non-AI feature set immediately.
To get an Anthropic API key: create an account at console.anthropic.com, add a credit card, and generate a key. Load $5 and it'll last a long time at Draft Desk's conservative usage patterns.
Once you're in:
Write in the center editor. Everything autosaves.
Use the left panel for AI settings — tone target, writing intent, transform, companion log.
Use the right panel (Editor Notes) for AI feedback, grammar notes, suggestions, and your own manual notes.
Open Assist Mode (Aa button on mobile dock, or the Assist button on desktop) for focus tools, sounds, readability, and accessibility options.
Templates are in the settings bar above the editor. Smart Share is right next to them.
⌘F opens Find & Replace. History is in the settings bar. Stats shows your word count, readability, and writing heatmap.
On mobile: save the page to your home screen for the full app experience. The bottom dock handles navigation. Everything works offline after the first load.
How It's Grown
Draft Desk started as a concept: what if the AI was in the background, not the foreground?
The first version was minimal — a textarea, a companion log, and a grammar check that fired on pause. The AI features worked. The writing experience didn't.
From there it grew steadily outward. The document manager came first, because writing across multiple pieces without losing context was the first real friction. Then version history, because the fear of losing work is a real creative inhibitor. Then focus mode, because the writing environment matters as much as the feedback.
The mobile rebuild was substantial. The original UI assumed a wide screen — the AI pill row, the format toolbar, the three-panel layout. Getting that to work on a 390px iPhone screen without losing any capability meant rebuilding the navigation entirely with the bottom dock, making the assist panel a slide-up sheet, collapsing the left panel by default, and moving the font/size controls into a dedicated row.
The no-API feature tier grew out of a design principle I kept coming back to: the app should feel complete even to someone who never connects AI to it. That thinking drove the addition of Find & Replace, Readability Score, Writing Sounds, Sentence Focus, Paragraph Focus, the Writing Heatmap, Smart Templates, Manual Notes, and Smart Share — all built to work locally, instantly, with no key required.
The AI cost controls went through multiple iterations. The current implementation has three layers: the features flags (which deactivate when no key is present), a per-session action limit with a visible warning when you're approaching it, and a tab visibility guard that pauses all AI calls when the browser tab is hidden. The grammar debounce fires after three seconds of inactivity. The tone interval fires every two and a half minutes. Suggestions have a two-minute cooldown and require at least 150 new characters since the last check. The idea is that AI should feel like a thoughtful observer — not a process that's constantly running.
The companion log itself has been the most iterative part. Getting the messages right — specific enough to be useful, varied enough to not feel repetitive, editorial enough to fit the tone of the tool — is ongoing work. The voice persona system (Direct, Encouraging, or Strict) lets writers pick how they want to be addressed. The writing intent feature came out of realizing that "tone" is only half the question — the other half is what you're trying to make the reader do.
The current version is the one I'm genuinely happy to put in front of other writers. It's not finished — nothing worth using ever is — but it's coherent, it's fast, it's honest about what it does, and it respects the most important thing about writing: that the words are yours.
Try it at draftdesk.cloud. The full app is free to use without an AI key. If you want the companion features, bring your own Anthropic key and you'll spend pennies per session.
