Comments and Mentions
Keep discussion on the record instead of in chat and email.
What it adds
Threaded comments attached to a record, with @-mentions that notify the person mentioned.
What your agent is told to do
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What your agent is told to do
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Attach comments to a record polymorphically so the same component works across object types rather than being rebuilt per model.
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Store mentions as structured references to user IDs, not as raw text parsed at render time. Display names change; IDs do not.
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Restrict the mention picker to users who can already see the record, and reject mentions of anyone else on the server.
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Notify each mentioned user once per comment. Track what has been sent so an edit or a delivery retry cannot fire a second notification.
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Do NOT allow raw HTML in comment bodies. Sanitize to a small allowlist and render links with rel=noopener — comments are the most-pasted surface in any app.
Edge cases it handles
6
Edge cases it handles
6- Editing a comment to add a new mention should notify only the newly added person, never everyone again.
- A deleted user's past mentions must still render as inert text, not as a broken link or a blank.
- Deleting a comment with replies must not orphan them — either soft-delete with a tombstone or cascade deliberately.
- Mentioning someone must never grant them access. If they cannot open the record, the notification is a dead link.
- Comments arriving in realtime must insert in a stable order, and must not scroll the reader away from what they were reading.
- Show edited and deleted state. A silently rewritten comment is a trust problem in any thread people rely on.
Definition of done
8
Definition of done
8- Comments attach to any supported record type through one implementation.
- Mentions are stored as user references and survive display-name changes.
- Only users with access to the record can be mentioned, enforced server-side.
- Each mention notifies exactly once, including across edits and retries.
- Comment bodies are sanitized to an allowlist and links carry rel=noopener.
- Edited and deleted comments are visibly marked and ordering stays stable under realtime updates.
- The feature matches the existing design system.
- No existing functionality is broken.
Related features
Voice Notes
Voice Notes
Say it instead of typing it, and attach the recording where the conversation is.
What it does
In-app recording of short audio notes attached to a record, comment, or message.
How it works
- 1 Add recording to the places where people already leave text, most likely alongside Comments and Mentions, so a voice note is another kind of comment rather than a separate feed nobody checks.
- 2 Store the recording through the app's existing file upload path so a voice note inherits the same retention and access rules as any other attachment on the record, and disappears with the record when it is deleted.
- 3 Show a live duration and a simple level meter while recording, and let the user review and discard before it is sent. Nobody should be committed to a recording the instant they stop.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/voice-notes
Direct Messages
Direct Messages
Let two users hold a private conversation inside the app instead of leaving to email.
What it does
One-to-one private threads with message history, per-conversation unread counts, and blocking.
How it works
- 1 Build the conversation list, the thread view, and the unread badge. Keep the first version to one-to-one threads only and defer group conversations, reactions, threading, and file attachments rather than shipping all of them half-finished.
- 2 Reuse the app's existing Read and Unread State and Notification Center rather than inventing a second unread mechanism and a second alert path. A message notification should sit alongside every other notification the user gets.
- 3 Reuse the composer, mention handling, and rendering rules from Comments and Mentions instead of writing a second message editor with subtly different escaping.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/direct-messages
Reactions
Reactions
Let people acknowledge something without writing another comment.
What it does
Lightweight reactions on content, with accurate counts, who-reacted detail, and text labels.
How it works
- 1 Store one row per user, per reaction type, per item, with a uniqueness constraint. That constraint is what makes a double-tap harmless.
- 2 Make the toggle idempotent: reacting twice leaves one reaction, un-reacting twice leaves none. Never derive state from a count you incremented.
- 3 Update the count optimistically for the person who clicked, then reconcile with the server response and roll back visibly on failure.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/reactions
How it works
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1
Copy the link
Grab the Markdown instruction URL for this feature.
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2
Give it to your AI
Paste it into Claude Code, Cursor, v0, Lovable — whatever you build with.
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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.