Show HN: no-fi – a linter for the ASCII wireframes agents draw

A developer released no-fi, an agent skill that makes Claude draw UI wireframes as plain ASCII and box-drawing text instead of styled mockups, installable via `npx no-fi-skill` into `~/.claude/skills/no-fi` or by uploading no-fi.zip under Settings, Capabilities, Skills on claude.ai. The skill enforces seven rules — printable ASCII plus box-drawing and block characters, double-lined outer frames with single-lined inner boxes, an 80-character line limit, fenced code-block output, no colors or icons, a fixed 44-element vocabulary in 7 groups (Structure, Fields, Buttons, Feedback, Navigation, Data, Charts), and validation by a bundled Node and Python checker script before results are shown. The release matters to teams using coding agents because it constrains generated wireframes to structure and content that can be reviewed and validated mechanically rather than reacted to on visual style.

Wireframes without the distraction. no-fi is an agent skill that draws UI as plain text, so a team argues about layout, content, and flow instead of color and type. Ask for a screen and Claude answers with a monospaced drawing: boxes, fields, buttons, tables, and bar charts made from plain characters. There are no colors, fonts, or icons to react to, so the only thing left to discuss is structure. ╔══════════════════════════════════════╗ ║ SIGN IN ║ ║ ║ ║ ┌──────────────────────────────────┐ ║ ║ │ Email │ ║ ║ │ ana@acme.com │ ║ ║ │ │ ║ ║ │ Password │ ║ ║ │ │ ║ ║ │ │ ║ ║ │ Sign in Forgot? │ ║ ║ └──────────────────────────────────┘ ║ ╚══════════════════════════════════════╝ The outer frame is double-lined, every box inside it is single-lined, and the primary button gets double brackets. Larger screens are in Examples examples . Pick one. Each puts the no-fi skill folder where your agent loads skills from. With a prompt Copy the install prompt from no-fi.dev https://no-fi.dev/ get-started and paste it into Claude Code or any agent. It runs the npx command below, or downloads the files one by one if it can't run npx. With npx npx no-fi-skill This copies the skill into ~/.claude/skills/no-fi . Add --project to install it into ./.claude/skills/no-fi instead, and --force to replace an existing install. With the skills CLI npx skills add p-a-u-l-i-e/no-fi --skill no-fi By hand git clone https://github.com/p-a-u-l-i-e/no-fi.git cp -R no-fi/plugin/skills/no-fi ~/.claude/skills/ On claude.ai Download no-fi.zip https://no-fi.dev/no-fi.zip and upload it under Settings, Capabilities, Skills. It holds only the skill folder. GitHub's Download ZIP holds the whole repository, which claude.ai won't take as a skill. The skill is plain text plus one small checker script, in Node and Python, so you can read every file before you install it. Ask for a screen the way you would ask a designer for a sketch. Saying wireframe or sketch is enough to load the skill, or type /no-fi in Claude Code. Wireframe a send-money form with three steps. Draw the settings page for notification preferences. Let's talk through the transactions table before we design it. Claude replies with a fenced code block, runs the checker on it, and adds a note below the drawing for anything that needs a visual described in words. Seven rules keep every wireframe readable. The full text is in SKILL.md https://github.com/p-a-u-l-i-e/no-fi/blob/main/plugin/skills/no-fi/SKILL.md . 1. Plain characters, plus box-drawing. Printable ASCII, box-drawing borders, and block characters for bars and charts. No emoji, no tabs. 2. Double outside, single inside. The outermost container uses double lines. Every box inside it uses single lines. 3. Fixed width. No line is longer than 80 characters, and every box is the same width on every row. 4. Code block. Output is always a fenced block, so alignment holds. 5. Describe, don't decorate. No colors, fonts, or icons. Name anything visual in a note below the drawing. 6. Use the vocabulary. Draw each element as the tables show. Don't invent symbols. 7. Validate. Run the checker and fix every failure before showing the result. 44 elements in 7 groups: Structure, Fields, Buttons, Feedback, Navigation, Data, and Charts. Each element looks like the component it stands for: - An input is one line. A textarea is a taller card with a // grip. - A badge is a pill, Paid . A tag is removable, <Food x . - A button has brackets, and the primary one has double brackets. - Open states are drawn open: a select with its menu below, an accordion with its content under it. - Modals , toasts , and tooltips are cards drawn inside the screen they sit on. The complete table, with a drawing and a note for each element, is in SKILL.md https://github.com/p-a-u-l-i-e/no-fi/blob/main/plugin/skills/no-fi/SKILL.md . The same data is in vocabulary.json https://github.com/p-a-u-l-i-e/no-fi/blob/main/plugin/skills/no-fi/vocabulary.json . Seven finished screens in examples/ https://github.com/p-a-u-l-i-e/no-fi/blob/main/plugin/skills/no-fi/examples , built to use the whole vocabulary: | Screen | File | |---|---| | Fintech dashboard | fintech-dashboard.txt https://github.com/p-a-u-l-i-e/no-fi/blob/main/plugin/skills/no-fi/examples/fintech-dashboard.txt | | Send money form | send-money-form.txt https://github.com/p-a-u-l-i-e/no-fi/blob/main/plugin/skills/no-fi/examples/send-money-form.txt | | Transactions table | transactions-table.txt https://github.com/p-a-u-l-i-e/no-fi/blob/main/plugin/skills/no-fi/examples/transactions-table.txt | | Spending report | spending-report.txt https://github.com/p-a-u-l-i-e/no-fi/blob/main/plugin/skills/no-fi/examples/spending-report.txt | | Card details | card-details.txt https://github.com/p-a-u-l-i-e/no-fi/blob/main/plugin/skills/no-fi/examples/card-details.txt | | Notification settings | settings-notifications.txt https://github.com/p-a-u-l-i-e/no-fi/blob/main/plugin/skills/no-fi/examples/settings-notifications.txt | | Activity patterns | activity-patterns.txt https://github.com/p-a-u-l-i-e/no-fi/blob/main/plugin/skills/no-fi/examples/activity-patterns.txt | Your agent checks every wireframe before it shows you one. To check one yourself, from anywhere: npx no-fi-skill check wireframe.txt The checker also ships with the skill, in Node and Python with the same output. From an install, or from this repository: node ~/.claude/skills/no-fi/scripts/check wireframe.mjs wireframe.txt python3 plugin/skills/no-fi/scripts/check wireframe.py wireframe.txt It fails on unsupported characters, tabs, ASCII box borders, boxes that don't close or line up, mixed double and single lines in one box, a double-line box nested inside another box, table dividers that don't land in the same column, progress bars whose fill disagrees with their percentage, bar chart rows whose length disagrees with their value, heatmaps and stacked columns without a legend, and column charts that don't say what a row is worth. plugin/skills/no-fi/vocabulary.json is the source of truth. These scripts live in scripts/ , outside the skill, so they don't ship to users. After editing the vocabulary, run: python3 scripts/sync vocabulary.py rewrite the tables in SKILL.md node scripts/check coverage.mjs every element appears in an example node plugin/skills/no-fi/scripts/check wireframe.mjs plugin/skills/no-fi/examples/ .txt python3 scripts/check coverage.py gives the same coverage output without Node. plugin/ the Claude plugin .claude-plugin/ plugin.json skills/no-fi/ the skill SKILL.md rules and vocabulary tables vocabulary.json the element vocabulary as data examples/ finished example screens scripts/ the wireframe checker scripts/ maintainer scripts: vocabulary sync and coverage bin/no-fi-skill.mjs the npx no-fi-skill command assets/ README images site/ the no-fi.dev site