hotedit

hotedit

Edit any HTML file in your browser — text, styles, layout and charts — and save the changes straight back into the file. Built for the HTML reports that AI assistants write.

[hotedit tour: edit text, restyle, change Plotly, Chart.js, Vega-Lite and Mermaid charts, edit maths, add and drag blocks, ask the AI to change one block live]

▶ Watch the narrated 95-second tour (MP4, sound on) · or try it yourself: npx hotedit demo

AI assistants produce a lot of HTML: reports, dashboards, summaries. They look great, but fixing a typo, renaming a chart title or moving a section means digging through thousands of lines of generated markup, or asking the AI again. hotedit opens the page in your browser so you can click what you see and change it. Only the bytes you changed are rewritten, so the file stays clean, diff-friendly and yours.

It doesn't change what your AI makes. Let it write the report exactly as it normally would, at the same quality and with the same charts, design and depth. hotedit only adds the ability to edit it afterwards. Nothing is simplified or re-generated, and nothing is added to the file.

Quick start (30 seconds)

You need Node.js 18+. Then:

npx hotedit report.html

Your browser opens the page. Click ✎ Edit (or press ⌥E / Alt+E), click any text and type. Changes are saved into report.html as you go, ⌘Z / Ctrl+Z undoes them, and ✓ Done (top right, always in the same place) saves anything still open and stops editing. Hover any button to see its shortcut: they are all ⌥ / Alt + a key (⌥E edit, ⌥A ask AI, ⌥S style, ⌥I add, ⌥D duplicate, ⌥⌫ delete, ⌥↑/↓ move), so plain keys never trigger anything and typing is never affected.

Just want to see it? Open a sample report (charts, maths, diagrams) in a throwaway copy:

npx hotedit demo

Not sure which file? Run it with no file and click one from the list:

npx hotedit          # lists the HTML files in this folder

To install it permanently, so you can just type hotedit:

npm install -g hotedithotedit report.html

What you can do

Things that are generated by the page's own scripts, such as KaTeX maths, Mermaid output or tables built in JavaScript, are never saved as rendered output. hotedit opens their source instead.

Working with AI agents

✨ Built in: ask, and watch it change

Click ✨, say what you want ("make this shorter", "turn the bars orange", "add a row for March"), and press Do it. The AI reads the page, makes small edits in the file and each one shows up in your browser straight away, without reloading. Connect it once with ⚙, using an AI you already have:

• Claude Code: your Claude plan. Install Claude Code and run claude once to log in.
• Codex: your ChatGPT plan. npm install -g @openai/codex and run codex once to log in.
• Anthropic API key: paste a key (kept only on your computer, in ~/.htmledit/config.json), or set ANTHROPIC_API_KEY. Uses claude-opus-5-5 unless you pick another model.
• Other agent: any agent CLI that has hotedit's MCP tools, e.g. after gemini mcp add hotedit npx -y hotedit mcp, type gemini -y. The request is added as the last argument (or wherever you put {prompt}).

Change just one thing. With a block selected, the panel says Only changes: … and the AI can edit that block only (for a chart, also the code that draws it). Anything else it tries is rejected. Click another block to point it there, or Whole page to lift the limit. All its changes are normal undo steps.

Your own agent, live (MCP)

Give any coding agent that speaks MCP (Claude Code, Codex, Cursor, Gemini CLI…) hotedit's tools, and it can open a report in your browser and edit it while you watch:

claude mcp add hotedit -- npx -y hotedit mcpcodex mcp add hotedit -- npx -y hotedit mcp

Tools: open (opens the file in hotedit and your browser), outline, read and edit (saved and shown live). The agent finds pages you already have open in hotedit, too.

Skill: your agent's reports open in hotedit by themselves

Install it once. Your agent then writes reports that are easy to edit (text in HTML, chart specs inline), and every HTML report it writes opens in hotedit in your browser automatically, ready to edit. Later edits by the agent show up on the page live.

As a Claude Code plugin (skill, auto-open hook and MCP tools in one go):

/plugin marketplace add Thewhey-Brian/hotedit/plugin install hotedit@hotedit

Or from the command line:

npx hotedit skill install            # Claude Code, all projects (~/.claude)npx hotedit skill install --project  # Claude Code, this project only (./.claude)npx hotedit skill install --codex    # Codex (~/.codex)

This adds the skill and a small hook that runs after the agent writes a file. It ignores files that aren't HTML, pages that belong to an app or website (under src/, public/, node_modules/… or with template tags), and pages already open. The page is served in the background, and the server stops by itself once you've closed it for a while. Your other settings and hooks are left as they are.

• Skill only, no auto-open: add --no-auto. Pause it for one session: HOTEDIT_AUTO=0.
• Remove it: npx hotedit skill uninstall (add --codex or --project to match).
• Codex asks you once to trust the new hook.
• Other agents: npx hotedit skill print (paste it into AGENTS.md). They open a report with npx -y hotedit open report.html --background, which returns at once.

The skill only shapes how the HTML is written: text in the markup, chart specs inline. It tells the agent never to simplify or leave anything out for the sake of editing.

How it works

report.html ──parse (keeps source positions)──► served copy with element ids + editor overlay     ▲                                                              │     └──────── small byte patch ◄── map your edit back to source ◄──┘

• Your file is never "re-written". The editor and the element ids exist only in the copy the local server sends to your browser. Each edit becomes a minimal patch on the original bytes. Entities like ·, quote styles, indentation and comments elsewhere stay exactly as they were.
• Charts are edited in their source. The chart spec literal in the page's <script> is patched value by value, keeping its own quote and key style.
• Safe by default.
  • A backup is taken when a session starts (~/.htmledit/backups/).
  • Undo and redo cover every change.
  • If the file changes on disk (say, your agent edited it), the page updates in place.
  • Files that aren't UTF-8 are refused rather than corrupted.
  • The server only listens on 127.0.0.1 and checks a per-session token.

FAQ

Does it work on any HTML file? Yes, any local .html file: hand-written, AI-generated, or exported from Jupyter, plotly.py, R Markdown or Quarto. It is tested on pages with KaTeX, Mermaid, inline SVG charts, JavaScript-built dashboards, base64 images and deliberately odd markup.

Will it mess up my file? It is designed not to. Every test page is opened, every editable element is saved unchanged, and the file must stay byte-identical. Each real edit must produce exactly the expected diff.

Does it need the internet? No, hotedit runs locally. Your page may load its own libraries from a CDN, as many AI reports load KaTeX or Plotly.

Which browsers? Any modern browser. Automated tests run in Chromium.

Can I edit content that a script builds? Use ⋯ → Edit HTML on the script's block, or ask the AI with ✨.

Limitations

• One HTML file at a time. External .css and .js files are not edited, and styles are written as inline style attributes.
• Chart specs must be literals in an inline <script> (directly, or through const spec = {...}). Specs computed at runtime or loaded from separate files open as source.
• Undo history lasts for the session. Backups persist.

Development

git clone https://github.com/Thewhey-Brian/hotedit && cd hoteditnpm installnpx playwright install chromium   # browser for the end-to-end testsnpm test                          # unit, CLI and real-browser tests (~3 min)node demo/audio.mjs               # tour narration, sound effects, music (ElevenLabs key)node demo/record.js               # re-record the tour video + GIF (needs ffmpeg)

See CONTRIBUTING.md and docs/ARCHITECTURE.md.

Get involved

hotedit is young and contributions are very welcome. Good places to start:

• Try it on your own AI-generated reports and open an issue for anything it can't edit. A sample file helps most.
• Pick up a good first issue.
• Share ideas or show what you made in Discussions.

Roadmap: more chart libraries (ECharts, Observable Plot, Bokeh), editing external CSS, a VS Code extension, and guides for more agents (Gemini CLI, Cursor, OpenCode).

Related tools

• html-visual-editor has a nice touch-up UI, but downloads a new file and has no chart editing.
• Lavish has a great agent feedback loop, but you can't edit the page yourself.
• GrapesJS, VvvebJs and Pinegrow are full page builders that re-serialise documents.
• document.designMode saves whatever the scripts rendered.

License

MIT