Make a vibe-coded site feel human with a one-page Master Design Brief

TL;DR in plain English

• Pick 1–2 primary emotions (e.g., calming, energetic) and record them in a single-page Master Design Brief so the site has a consistent voice (source: https://news.ycombinator.com/item?id=49287430).
• Follow a short process: whiteboard → principles → mental image → palette → hybrid visuals → Master Design Brief (source: https://news.ycombinator.com/item?id=49287430).
• Generate several AI visuals and always hand-edit the chosen hero so it reads human, not generic AI. Keep design choices tightly restricted: palette, type, spacing (source: https://news.ycombinator.com/item?id=49287430).

Methodology note: this summary follows the "Design with a Soul" process described in the linked writeup and preserves its order and core recommendations (source: https://news.ycombinator.com/item?id=49287430).

What you will build and why it helps

You will produce a compact design package that makes an AI-assisted ("vibe-coded") site feel deliberate and human. The package centers on a one-page Master Design Brief and a small set of assets so decisions are fast and consistent (source: https://news.ycombinator.com/item?id=49287430).

Typical package contents:

| Asset | Purpose | Where to store | |---|---|---| | Master Design Brief (HTML/slide) | Single source of truth for ambiance, principles, palette, fonts | Repo root or docs/ | design-tokens.json | Minimal tokens wired into CSS variables | repo/assets/ | Hero image (AI base + hand edits) | Primary visual with human marks to avoid generic AI feel | repo/assets/images/

Plain-language rationale: a focused brief plus a tiny token file prevents design drift. The brief answers: what feeling, what colours, what visual language, what image anchors the page. When the team follows that single page, the site reads as a single voice even when parts were AI-generated (source: https://news.ycombinator.com/item?id=49287430).

Before you start (time, cost, prerequisites)

• Timebox: plan a short whiteboard session to set the ambiance and principles (the original recommends a whiteboard start) (source: https://news.ycombinator.com/item?id=49287430).
• Cost: can be $0 using free AI tools and a free image editor; optionally a small paid edit for $0–$50 (source: https://news.ycombinator.com/item?id=49287430).
• Prerequisites:
  • A place to keep the Master Design Brief (simple HTML page or slide deck) (source: https://news.ycombinator.com/item?id=49287430).
  • An AI image tool to produce variants and an image editor for hand-touches (source: https://news.ycombinator.com/item?id=49287430).
  • Ability to commit files to your repo (design-brief.html, design-tokens.json, hero.*) and a minimal CI to enforce palette if desired (source: https://news.ycombinator.com/item?id=49287430).

Step-by-step setup and implementation

Follow the stages below and record outcomes in the Master Design Brief (source: https://news.ycombinator.com/item?id=49287430).

1. Whiteboard

• Pick 1–2 emotions as primary anchors. Write a single-sentence ambition at the top of the brief (source: https://news.ycombinator.com/item?id=49287430).

2. Principles

• Define 3–5 short guiding principles. Examples from the writeup include "less is more" and "ruthless elimination." Put them in the brief for fast decisions (source: https://news.ycombinator.com/item?id=49287430).

3. Mental image

• Add a short sensory metaphor (e.g., the author used a "creamy, sweet, lime liquor") to guide tone choices. This is internal guidance, not copy for users (source: https://news.ycombinator.com/item?id=49287430).

4. Colours and tones

• Use a palette picker and save hex values in the brief. Limit the palette to a small set (the writeup suggests keeping choices tight) (source: https://news.ycombinator.com/item?id=49287430).

5. Primary visuals

• Generate several AI variants, choose one, and hand-edit it: add texture, grain, a small hand-drawn accent, or crop to create human marks (source: https://news.ycombinator.com/item?id=49287430).

6. The Master Design Brief

• Combine ambiance, principles, palette, fonts, the hero visual, and component constraints into one page. Use it as the source of truth for decisions (source: https://news.ycombinator.com/item?id=49287430).

7. Tokens and wiring

• Export a minimal design-tokens.json and wire it to CSS variables so code follows the brief. Keep tokens small: palette, spacing scale, radius, font stack (source: https://news.ycombinator.com/item?id=49287430).

Example build commands (adjust to your workflow):

# build and deploy example commands
npm run build:css  # compiles tokens to CSS
git add design-tokens.json && git commit -m "Add design tokens" && git push origin feature/design-brief
DEPLOY_ENV=staging ./deploy.sh

Example minimal design-tokens.json to store in the repo:

{
  "color-1": "#F9FAFB",
  "color-2": "#E76F51",
  "space-1": "8px",
  "space-2": "16px",
  "radius-base": "8px",
  "font-stack": "Inter, system-ui, -apple-system, 'Segoe UI', Roboto"
}

(source: https://news.ycombinator.com/item?id=49287430)

Common problems and quick fixes

• Visuals still feel generic AI: pick one AI output and hand-edit it. Add texture, grain, or a small hand-drawn overlay to restore human signals (source: https://news.ycombinator.com/item?id=49287430).
• Colour drift: restrict the live CSS to the brief's hex values and remove off-palette codes from the build (source: https://news.ycombinator.com/item?id=49287430).
• Clutter: apply "ruthless elimination": delete UI elements that don't support the chosen ambiance (source: https://news.ycombinator.com/item?id=49287430).
• Large images slow pages: export efficient formats and responsive sizes; the writeup recommends producing responsive image variants (source: https://news.ycombinator.com/item?id=49287430).

Image conversion example commands:

# resize and convert to AVIF/WebP using sharp (example)
npx sharp hero.png --resize 1200 --toFormat avif -o hero-1200.avif
npx sharp hero.png --resize 960 --toFormat webp -o hero-960.webp

Quick enforcement idea: fail CI if CSS contains hex codes not listed in design-tokens.json to keep live styles aligned with the brief (source: https://news.ycombinator.com/item?id=49287430).

First use case for a small team

This process is well-suited to solo founders and very small teams who want a coherent, human-feeling front end quickly (source: https://news.ycombinator.com/item?id=49287430).

Tiny-team pattern (timeboxed):

1. 60–240 minute whiteboard session producing a one-page Master Design Brief (time estimate as a practical pattern; see Assumptions / Hypotheses) (source: https://news.ycombinator.com/item?id=49287430).
2. Generate multiple AI image variants, choose one, and hand-edit it.
3. Commit design-brief.html and design-tokens.json; add a CI check to prevent palette drift.

Roles and suggestive timeline (illustrative):

• Solo founder: whiteboard + brief — 60–240 min (pattern from the writeup) (source: https://news.ycombinator.com/item?id=49287430)
• Front-end engineer: wire tokens into CSS + place hero — 1–4 hours
• Micro-editor/contractor: hand-edit hero — 0.5–4 hours

Starter launch checklist:

• [ ] design-brief.html committed
• [ ] design-tokens.json committed
• [ ] hero.avif generated
• [ ] CI palette check added
• [ ] quick performance check run (staging)

(source: https://news.ycombinator.com/item?id=49287430)

Technical notes (optional)

Keep advanced implementation detail here so the Master Design Brief remains concise. The writeup emphasises process and human judgement over heavy tooling; a few repeatable technical patterns help.

Recommendations (implementation patterns):

• Export hero images at several widths and use srcset to serve the right size; three sizes is a common minimum (source: https://news.ycombinator.com/item?id=49287430).
• Keep design tokens minimal (palette, spacing scale, radius, font stack) and store them in the repo (source: https://news.ycombinator.com/item?id=49287430).
• Consider a feature flag for style changes so you can roll back quickly if a visual causes problems (source: https://news.ycombinator.com/item?id=49287430).

Performance check example (run on staging):

npx lighthouse https://staging.example.com --only-categories=performance --output=json --output-path=report.json

Acronyms (for clarity): LCP — Largest Contentful Paint; TBT — Total Blocking Time; CLS — Cumulative Layout Shift; RUM — Real User Monitoring (source: https://news.ycombinator.com/item?id=49287430).

What to do next (production checklist)

Assumptions / Hypotheses

• The step sequence (whiteboard → principles → mental image → palette → hybrid visuals → Master Design Brief) yields a more intentional-looking site than an unedited AI output (source: https://news.ycombinator.com/item?id=49287430).
• Numeric planning targets (use as assumptions for scheduling and QA): brief session 60–240 minutes; generate 4–6 AI variants; hand-edit final hero 30–120 minutes; palette count ~6 colours; base spacing 8px; export hero at 3 sizes (480, 960, 1200 px); keep the brief to 1 page; asset cost range $0–$50; canary 10% traffic for 48–72 hours; target planning thresholds: LCP 2500 ms, TBT 200 ms, CLS 0.1 (these numbers are offered as planning assumptions to operationalise the process).

(source: https://news.ycombinator.com/item?id=49287430)

Risks / Mitigations

• Risk: final visuals still read as generic AI. Mitigation: always hand-edit at least one selected variant and add human marks or texture (source: https://news.ycombinator.com/item?id=49287430).
• Risk: palette drift in CSS. Mitigation: keep the Master Design Brief in the repo and add CI checks that compare CSS hex codes to design-tokens.json (source: https://news.ycombinator.com/item?id=49287430).
• Risk: performance regressions from larger hero images. Mitigation: export efficient formats (AVIF/WebP), provide responsive srcset, and verify with a staging Lighthouse run (source: https://news.ycombinator.com/item?id=49287430).

Next steps

• Run a focused Master Design Brief session and commit design-brief.html to the repo (source: https://news.ycombinator.com/item?id=49287430).
• Create design-tokens.json and wire it into your CSS build using the build commands above (source: https://news.ycombinator.com/item?id=49287430).
• Generate 4–6 AI variants, pick one, hand-edit it, export AVIF/WebP in 3 sizes, and wire srcset (see image commands) (source: https://news.ycombinator.com/item?id=49287430).
• Deploy to staging, run Lighthouse, then canary the style (10% traffic) for 48–72 hours while monitoring LCP/TBT/CLS against the planning thresholds.

Reference: the "Design with a Soul" writeup that inspired this process (source: https://news.ycombinator.com/item?id=49287430).

Make a vibe-coded site feel human with a one-page Master Design Brief

Turn AI-assisted 'vibe-coded' pages into cohesive, human-feeling sites. Use a short process—whiteboard, emotional anchors, palette, hybrid AI+hand visuals, and…

https://aisignals.dev/posts/2026-08-13-make-a-vibe-coded-site-feel-human-with-a-one-page-master-design-brief

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