Rich Text Editor
Formatting tools that don't let pasted HTML wreck your app.
What it adds
A WYSIWYG editor for long-form fields, with a fixed set of supported formats and server-side sanitisation of everything it produces.
What your agent is told to do
5
What your agent is told to do
5-
1
Decide the supported format list first — headings, bold, italic, lists, links, quotes, code, images — and build the toolbar from it. An editor that accepts anything is an editor you cannot sanitise.
-
2
Sanitise on the server against an allowlist of tags and attributes, both on save and on render. Client-side sanitisation is a convenience, not a defence; the endpoint accepts whatever is posted to it.
-
3
Clean pasted content: strip inline styles, font tags, class names and comments from Word and Google Docs, and map what remains onto the supported formats.
-
4
Keep the editable region a real focusable control with a label, and make every toolbar action reachable by keyboard with its shortcut shown.
-
5
Do not store rendered HTML as the only copy if the app also needs plain text for search, previews or notifications — derive and store that too.
Edge cases it handles
6
Edge cases it handles
6- Content that looks empty but is a stray break or empty paragraph must count as empty for validation.
- Links must be checked for scheme — javascript: and data: URLs are the whole attack.
- Pasted images arrive as base64 or as remote URLs; decide whether to upload, rewrite or reject them, and never hotlink silently.
- Undo must survive a paste-and-clean operation as a single step, not unwind character by character.
- Autosave and formatting must not fight: a save mid-edit should not move the caret or reset the selection.
- Content authored before this editor existed must still open and save without being mangled.
Definition of done
8
Definition of done
8- Stored HTML is sanitised server-side against an explicit allowlist.
- Pasted Word and Docs content arrives clean and mapped to supported formats.
- Unsafe link schemes are rejected on save and on render.
- Every toolbar action has a keyboard path and headings produce real heading elements.
- Visually-empty content fails a required-field check.
- Legacy content round-trips through the editor unchanged.
- The feature matches the existing design system.
- No existing functionality is broken.
Related features
Voice Dictation
Voice Dictation
Put a microphone in text fields so people can speak their input instead of typing it.
What it does
A dictation control on the app's longer text inputs that transcribes speech into the field as the user talks.
How it works
- 1 Add the control to the fields where typing is genuinely tedious: long descriptions, notes, comments, and message bodies. A microphone on a postcode field is clutter.
- 2 Show interim results in the field as they arrive, visually distinct from committed text, so the speaker can see it is working and correct course before they finish.
- 3 Reuse the app's existing Voice Transcription for the server-side path so one recognition configuration and one set of language settings serve both dictation and recorded audio.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/voice-dictation
Help Text Pattern
Help Text Pattern
Put field guidance in one predictable place, phrased the same way every time.
What it does
A consistent treatment for the short explanatory text that sits with a field and its control.
How it works
- 1 Collect the guidance the app currently scatters across placeholders, tooltips, asterisked footnotes, and modal help, and move it into one slot beneath the field.
- 2 Keep guidance that is required to complete the field permanently visible. A format rule hidden behind a hover target is not available to a touch user or a keyboard user.
- 3 Write help as the rule the user needs before typing — the accepted format, the consequence of the choice — not as a restatement of the label.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/help-text-pattern
Form Section Pattern
Form Section Pattern
Break long forms into labelled sections people can scan instead of read.
What it does
A section pattern grouping related fields under a heading, a description, and its own actions.
How it works
- 1 Find the forms that have grown past a screenful — settings, profiles, checkout, configuration — and group their fields by the question each group answers, not by the table the columns come from.
- 2 Give each section a heading in the document's heading order and an optional one-line description, so screen reader and keyboard users can jump between sections.
- 3 Allow at most one level of nesting. A section inside a section inside a tab gives the user no orientation and pushes the fields into a narrow gutter.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/form-section-pattern
How it works
-
1
Copy the link
Grab the Markdown instruction URL for this feature.
-
2
Give it to your AI
Paste it into Claude Code, Cursor, v0, Lovable — whatever you build with.
-
3
It inspects, then implements
Your agent reads your existing app first, then adds the feature to fit it.
Works with your stack
These instructions are written to adapt. They tell the agent to detect your framework, match your existing design system, and reuse what you already have — rather than assuming a particular stack.
Need it tighter than that? Customize the feature and tell it exactly what you're running.