feat: soft-delete particles within a stream (#149)

Lets a particle's creator delete their own message from the TopBar
dropdown. Other viewers see a "This particle was deleted" tombstone in
place and playback auto-advances after ~2s, keeping indices stable for
concurrent watchers.

- Add optional deleted_at / deleted_by_human_id to non-container
  particle variants and isParticleDeleted helper.
- Add softDeleteParticle Firestore helper.
- New DeleteParticleOverlay confirmation and DeletedParticleView
  tombstone.
- Hide reactions (bar + 1-7 keybinding) on tombstoned particles.
- Show "Deleted particle" + Trash2 icon in the stream list preview.

Closes #146

https://claude.ai/code/session_01M2ShnZPvWfQzzvuu3Xm8b9

Co-authored-by: Claude <[email protected]>

js/src/api/types.ts

@@ -160,6 +160,16 @@ export type PaperProperties = z.infer<typeof PaperPropertiesSchema>;
 export const ReactionsSchema = z.record(z.string(), z.array(z.string())).optional();
 export type Reactions = z.infer<typeof ReactionsSchema>;
 
+// --- Tombstone (soft-delete) ---
+
+// Fields added to non-container particles when their creator deletes them.
+// We keep the doc around so concurrent viewers can see a "This particle was
+// deleted" message in place, rather than being jumped to the next particle.
+const TombstoneFields = {
+  deleted_at: z.coerce.date().optional(),
+  deleted_by_human_id: z.string().optional(),
+};
+
 export const REACTION_EMOJIS = ["\u{1F44D}", "\u{2764}\u{FE0F}", "\u{1F525}", "\u{1F440}", "\u{2705}", "\u{2753}", "\u{1F602}"] as const;
 
 export interface ParticlePropertiesMap {
@@ -203,11 +213,11 @@ export const ParticleSchema = z.discriminatedUnion("type", [
     // e.g. ["network:123"] - visible to everyone in the network
     visible_to: z.array(z.string()),
   }),
-  ParticleBaseSchema.extend({ type: z.literal("media"), properties: MediaPropertiesSchema, reactions: ReactionsSchema }),
-  ParticleBaseSchema.extend({ type: z.literal("file"), properties: FilePropertiesSchema }),
-  ParticleBaseSchema.extend({ type: z.literal("text"), properties: TextPropertiesSchema, reactions: ReactionsSchema }),
-  ParticleBaseSchema.extend({ type: z.literal("quest"), properties: QuestPropertiesSchema }),
-  ParticleBaseSchema.extend({ type: z.literal("paper"), properties: PaperPropertiesSchema }),
+  ParticleBaseSchema.extend({ type: z.literal("media"), properties: MediaPropertiesSchema, reactions: ReactionsSchema, ...TombstoneFields }),
+  ParticleBaseSchema.extend({ type: z.literal("file"), properties: FilePropertiesSchema, ...TombstoneFields }),
+  ParticleBaseSchema.extend({ type: z.literal("text"), properties: TextPropertiesSchema, reactions: ReactionsSchema, ...TombstoneFields }),
+  ParticleBaseSchema.extend({ type: z.literal("quest"), properties: QuestPropertiesSchema, ...TombstoneFields }),
+  ParticleBaseSchema.extend({ type: z.literal("paper"), properties: PaperPropertiesSchema, ...TombstoneFields }),
 ]);
 
 export type Particle = z.infer<typeof ParticleSchema>;
@@ -221,6 +231,11 @@ export function isContainerType(type: ParticleType): boolean {
   return CONTAINER_TYPES.has(type);
 }
 
+/** True when a non-container particle has been soft-deleted (tombstoned). */
+export function isParticleDeleted(particle: Particle): boolean {
+  return "deleted_at" in particle && particle.deleted_at != null;
+}
+
 // --- LiveKit types ---
 
 export const GetLivekitTokenResponseSchema = z.object({

js/src/features/particles/delete-particle-overlay.tsx

@@ -0,0 +1,94 @@
+import { useCallback, useEffect, useState } from "react";
+import { createPortal } from "react-dom";
+import { toast } from "sonner";
+import { Button } from "@/components/ui/button";
+import { softDeleteParticle } from "@/lib/firestore-particles";
+import { particlePath, toFirestoreDocPath } from "@/lib/particle-path";
+import type { Particle } from "@/api/types";
+
+interface DeleteParticleOverlayProps {
+  networkId: string;
+  streamId: string;
+  particle: Particle;
+  userId: string;
+  onClose: () => void;
+}
+
+export function DeleteParticleOverlay({
+  networkId,
+  streamId,
+  particle,
+  userId,
+  onClose,
+}: DeleteParticleOverlayProps) {
+  const [deleting, setDeleting] = useState(false);
+
+  const handleDelete = useCallback(async () => {
+    if (deleting) return;
+    setDeleting(true);
+    try {
+      const docPath = toFirestoreDocPath(
+        particlePath(networkId, [streamId, particle.id]),
+      );
+      await softDeleteParticle(docPath, userId);
+      toast.success("Particle deleted");
+      onClose();
+    } catch (e) {
+      const message = e instanceof Error ? e.message : "Failed to delete particle";
+      toast.error(message);
+      setDeleting(false);
+    }
+  }, [deleting, networkId, onClose, particle.id, streamId, userId]);
+
+  useEffect(() => {
+    const handler = (e: KeyboardEvent) => {
+      if (e.key === "Escape") {
+        e.preventDefault();
+        e.stopPropagation();
+        onClose();
+      }
+    };
+    window.addEventListener("keydown", handler, { capture: true });
+    return () => window.removeEventListener("keydown", handler, { capture: true });
+  }, [onClose]);
+
+  return createPortal(
+    <div className="fixed inset-0 z-[100]">
+      <div
+        className="absolute inset-0 bg-black/60 backdrop-blur-sm"
+        onClick={onClose}
+      />
+      <div className="absolute left-1/2 top-1/2 w-full max-w-sm -translate-x-1/2 -translate-y-1/2 rounded-2xl border border-white/10 bg-white/5 p-6 shadow-2xl backdrop-blur-xl">
+        <div className="mb-3 flex items-center justify-between">
+          <h2 className="text-sm font-semibold text-white/70">Delete this particle?</h2>
+          <span className="text-xs text-white/30">
+            <kbd className="rounded bg-white/10 px-1.5 py-0.5 font-mono text-xs">
+              Esc
+            </kbd>{" "}
+            to close
+          </span>
+        </div>
+
+        <p className="text-sm text-white/60">
+          This cannot be undone. Other viewers will see a "This particle was
+          deleted" message in its place.
+        </p>
+
+        <div className="mt-5 flex items-center justify-end gap-2">
+          <Button variant="ghost" size="sm" onClick={onClose} disabled={deleting}>
+            Cancel
+          </Button>
+          <Button
+            variant="destructive"
+            size="sm"
+            onClick={handleDelete}
+            disabled={deleting}
+          >
+            {deleting ? "Deleting…" : "Delete"}
+          </Button>
+        </div>
+      </div>
+    </div>,
+    document.body,
+  );
+}

js/src/features/particles/deleted-particle-view.tsx

@@ -0,0 +1,50 @@
+import { useEffect } from "react";
+import { Trash2 } from "lucide-react";
+import type { Particle } from "@/api/types";
+import { useNetwork } from "@/hooks/use-networks";
+
+// How long to linger on a tombstone before auto-advancing. Matches the
+// "reading" cadence of a short text particle.
+const TOMBSTONE_DURATION_MS = 2000;
+
+interface DeletedParticleViewProps {
+  particle: Particle;
+  networkId: string;
+  paused: boolean;
+  onEnded: () => void;
+}
+
+export function DeletedParticleView({
+  particle,
+  networkId,
+  paused,
+  onEnded,
+}: DeletedParticleViewProps) {
+  const network = useNetwork(networkId);
+  const deleterId =
+    "deleted_by_human_id" in particle ? particle.deleted_by_human_id : undefined;
+  const deleter = deleterId
+    ? network?.humans?.find((h) => h.id === deleterId)
+    : undefined;
+
+  useEffect(() => {
+    if (paused) return;
+
+    const timeout = setTimeout(onEnded, TOMBSTONE_DURATION_MS);
+    return () => clearTimeout(timeout);
+  }, [paused, onEnded, particle.id]);
+
+  return (
+    <div className="flex h-full w-full items-center justify-center bg-gradient-to-b from-black/40 via-black/20 to-black/40 px-8">
+      <div className="flex flex-col items-center gap-3 text-center">
+        <Trash2 className="text-white/40 size-6" />
+        <p className="text-white/70 text-base font-medium">
+          This particle was deleted
+        </p>
+        {deleter && (
+          <p className="text-white/40 text-xs">by {deleter.email_prefix}</p>
+        )}
+      </div>
+    </div>
+  );
+}

js/src/features/particles/particle-list-view.tsx

@@ -10,6 +10,7 @@ import {
   CircleCheck,
   StickyNote,
   Headphones,
+  Trash2,
   type LucideIcon,
 } from "lucide-react";
 import { cn } from "@/lib/utils";
@@ -23,13 +24,14 @@ import { Separator } from "@/components/ui/separator";
 import { Progress } from "@/components/ui/progress";
 import { Small } from "@/components/ui/typography";
 import { Button } from "@/components/ui/button";
-import type { Particle, StreamProperties } from "@/api/types";
+import { isParticleDeleted, type Particle, type StreamProperties } from "@/api/types";
 import type { StreamParticle } from "@/hooks/use-stream-particles";
 import { useNetwork } from "@/hooks/use-networks";
 import { useStreamAutoplay } from "@/hooks/use-stream-autoplay";
 import { StreamContextMenu } from "@/features/particles/stream-context-menu";
 
 function getParticleTypeIcon(particle: Particle): LucideIcon {
+  if (isParticleDeleted(particle)) return Trash2;
   switch (particle.type) {
     case "text":
       return MessageSquare;
@@ -52,6 +54,7 @@ function getParticleTypeIcon(particle: Particle): LucideIcon {
 }
 
 function getMessagePreview(particle: Particle): string {
+  if (isParticleDeleted(particle)) return "Deleted particle";
   switch (particle.type) {
     case "text":
       return particle.properties.content;

js/src/features/particles/stream-top-bar.tsx

@@ -2,7 +2,7 @@ import { useState } from "react";
 import { useNavigate } from "react-router-dom";
 import { useAuthStore } from "@/stores/auth-store";
 import { apiClient } from "@/api/client";
-import type { Particle } from "@/api/types";
+import { isParticleDeleted, type Particle } from "@/api/types";
 import { particlePath, toFirestoreDocPath } from "@/lib/particle-path";
 import { Avatar, AvatarFallback, AvatarGroup } from "@/components/ui/avatar";
 import { Tooltip, TooltipContent, TooltipTrigger } from "@/components/ui/tooltip";
@@ -14,9 +14,10 @@ import {
   DropdownMenuItem,
   DropdownMenuTrigger,
 } from "@/components/ui/dropdown-menu";
-import { Settings, CircleCheckBig, CircleDot, EllipsisVertical, Pencil, Globe } from "lucide-react";
+import { Settings, CircleCheckBig, CircleDot, EllipsisVertical, Pencil, Globe, Trash2 } from "lucide-react";
 import { updateStreamStatus } from "@/lib/firestore-particles";
 import { RenameStreamOverlay } from "@/features/particles/rename-stream-overlay";
+import { DeleteParticleOverlay } from "@/features/particles/delete-particle-overlay";
 import { StreamMembersOverlay } from "@/features/particles/stream-members-overlay";
 import { parseVisibleTo } from "@/lib/stream-visibility";
 import { Breadcrumb, BreadcrumbItem, BreadcrumbList, BreadcrumbPage, BreadcrumbSeparator } from "@/components/ui/breadcrumb";
@@ -56,6 +57,15 @@ export function TopBar({ networkId, particle, streamParticle }: TopBarProps) {
   const isCreator = !!userId && userId === streamParticle.created_by_human_id;
   const [renameOpen, setRenameOpen] = useState(false);
   const [membersOpen, setMembersOpen] = useState(false);
+  const [deleteOpen, setDeleteOpen] = useState(false);
+
+  const canDeleteParticle =
+    !!particle &&
+    !!userId &&
+    particle.created_by_human_id === userId &&
+    particle.type !== "stream" &&
+    particle.type !== "folder" &&
+    !isParticleDeleted(particle);
 
   const huddleParticipants = streamParticle.huddle_active_participants ?? [];
   const hasActiveHuddle = huddleParticipants.length > 0;
@@ -170,6 +180,15 @@ export function TopBar({ networkId, particle, streamParticle }: TopBarProps) {
               Rename stream
             </DropdownMenuItem>
           )}
+          {canDeleteParticle && (
+            <DropdownMenuItem
+              onSelect={() => setDeleteOpen(true)}
+              variant="destructive"
+            >
+              <Trash2 className="size-4" />
+              Delete particle
+            </DropdownMenuItem>
+          )}
           <DropdownMenuItem onSelect={() => navigate("/settings")}>
             <Settings className="size-4" />
             Settings
@@ -185,6 +204,16 @@ export function TopBar({ networkId, particle, streamParticle }: TopBarProps) {
         />
       )}
 
+      {deleteOpen && canDeleteParticle && particle && userId && (
+        <DeleteParticleOverlay
+          networkId={networkId}
+          streamId={streamParticle.id}
+          particle={particle}
+          userId={userId}
+          onClose={() => setDeleteOpen(false)}
+        />
+      )}
+
       {membersOpen && (
         <StreamMembersOverlay
           networkId={networkId}

js/src/features/particles/stream-view.tsx

@@ -2,13 +2,14 @@ import { useState, useEffect, useEffectEvent, useCallback, useRef } from "react"
 import { useNavigate } from "react-router-dom";
 import { useAuthStore } from "@/stores/auth-store";
 import { apiClient } from "@/api/client";
-import { type Particle, REACTION_EMOJIS } from "@/api/types";
+import { isParticleDeleted, type Particle, REACTION_EMOJIS } from "@/api/types";
 import { parseParticlePath, particlePath, toFirestoreDocPath, type ParticlePath } from "@/lib/particle-path";
 import { ComposeOverlay, type ComposeStep } from "@/features/compose/compose-overlay";
 import { PlaybackPageIndicator } from "@/features/particles/playback-page-indicator";
 import { MediaParticleView, type MediaParticleHandle } from "@/features/particles/media-particle-view";
 import { TextParticleView } from "@/features/particles/text-particle-view";
 import { FallbackParticleView } from "@/features/particles/fallback-particle-view";
+import { DeletedParticleView } from "@/features/particles/deleted-particle-view";
 import { VideoAudioToggle } from "@/components/video-audio-toggle";
 import { useMediaSettingsStore } from "@/stores/media-settings-store";
 import { KeybindingsOverlay, type KeybindingGroup } from "@/components/keybindings-overlay";
@@ -25,6 +26,7 @@ import { cn } from "@/lib/utils";
 import { useMount } from "react-use";
 
 function getReactions(particle: Particle): Record<string, string[]> | undefined {
+  if (isParticleDeleted(particle)) return undefined;
   if (particle.type === "media" || particle.type === "text") return particle.reactions;
   return undefined;
 }
@@ -176,6 +178,7 @@ function StreamViewInner({ path, streamParticle }: StreamViewProps) {
 
   const handleToggleReaction = useCallback((emoji: string) => {
     if (!authedUser || !currentParticle) return;
+    if (isParticleDeleted(currentParticle)) return;
 
 
     const currentParticleDocPath = currentParticle
@@ -370,6 +373,17 @@ function StreamViewInner({ path, streamParticle }: StreamViewProps) {
 
   // Render particle content inline
   function renderParticle(particle: Particle) {
+    if (isParticleDeleted(particle)) {
+      return (
+        <DeletedParticleView
+          key={particle.id}
+          particle={particle}
+          networkId={networkId}
+          paused={paused}
+          onEnded={next}
+        />
+      );
+    }
     switch (particle.type) {
       case "media":
         return (
@@ -432,7 +446,7 @@ function StreamViewInner({ path, streamParticle }: StreamViewProps) {
       </div>
 
       {/* Reaction bar — always visible */}
-      {currentParticle && (
+      {currentParticle && !isParticleDeleted(currentParticle) && (
         <div className="absolute right-4 top-1/2 -translate-y-1/2 z-10">
           <ReactionBar
             reactions={getReactions(currentParticle)}

js/src/lib/firestore-particles.ts

@@ -30,10 +30,12 @@ import type { Particle, ParticleType, ParticlePropertiesMap, Reactions } from "@
 const particleConverter: FirestoreDataConverter<Particle> = {
   toFirestore(particle: Particle): DocumentData {
     const { id: _id, created_at, updated_at, ...rest } = particle;
+    const deletedAt = "deleted_at" in particle ? particle.deleted_at : undefined;
     return {
       ...rest,
       created_at: Timestamp.fromDate(created_at),
       ...(updated_at && { updated_at: Timestamp.fromDate(updated_at) }),
+      ...(deletedAt && { deleted_at: Timestamp.fromDate(deletedAt) }),
     };
   },
   fromFirestore(
@@ -99,6 +101,8 @@ const particleConverter: FirestoreDataConverter<Particle> = {
           created_by_human_id: raw.created_by_human_id,
           updated_at: raw.updated_at ? (raw.updated_at as Timestamp).toDate() : undefined,
           reactions: raw.reactions ?? undefined,
+          deleted_at: raw.deleted_at ? (raw.deleted_at as Timestamp).toDate() : undefined,
+          deleted_by_human_id: raw.deleted_by_human_id ?? undefined,
         });
       }
       default:
@@ -364,6 +368,24 @@ export async function updateStreamStatus(
   await updateDoc(particleRef, { status, updated_at: serverTimestamp() });
 }
 
+/**
+ * Soft-delete (tombstone) a non-container particle. The Firestore doc stays
+ * in place so concurrent viewers see the deletion inline rather than being
+ * bumped to an adjacent particle. Idempotent — re-calling on an already
+ * tombstoned doc just refreshes the timestamp.
+ */
+export async function softDeleteParticle(
+  docPath: string,
+  humanId: string,
+): Promise<void> {
+  const particleRef = typedDoc(docPath);
+  await updateDoc(particleRef, {
+    deleted_at: serverTimestamp(),
+    deleted_by_human_id: humanId,
+    updated_at: serverTimestamp(),
+  });
+}
+
 export async function updateStreamPlaybackMarker(
   docPath: string,
   humanId: string,