feat(mobile): surface prominent activity status and metadata

- Keep prominent activity rows visible with lifecycle status and provider metadata
- Move feed sizing logic into tested helpers and preserve native measurement for activity groups

Author: juliusmarminge

apps/mobile/src/features/threads/ThreadFeed.tsx

@@ -106,9 +106,7 @@ import { uuidv4 } from "../../lib/uuid";
 import {
   resolveMarkdownFontSizes,
   resolveNativeMarkdownTypography,
-  scaledTypographyLineHeight,
 } from "../../lib/appearancePreferences";
-import { MOBILE_TYPOGRAPHY } from "../../lib/typography";
 import { useAppearancePreferences } from "../settings/appearance/AppearancePreferencesProvider";
 import { useAppearanceCodeSurface } from "../settings/appearance/useAppearanceCodeSurface";
 import { markdownFileIconSource } from "@t3tools/mobile-markdown-text/file-icons";
@@ -128,13 +126,8 @@ import {
   resolveThreadFeedLiveFollow,
   type ThreadFeedLiveFollowEvent,
 } from "./thread-feed-live-follow";
-import {
-  collapsedWorkLogHeight,
-  ThreadDisclosureChevron,
-  ThreadWorkGroupToggle,
-  ThreadWorkLog,
-  WORK_GROUP_TOGGLE_HEIGHT,
-} from "./thread-work-log";
+import { ThreadWorkGroupToggle, ThreadWorkLog } from "./thread-work-log";
+import { resolveThreadFeedFixedItemSize } from "./thread-feed-item-size";
 import { useMarkdownCodeHighlight } from "./markdownCodeHighlightState";
 import { useAssetUrl } from "../../state/assets";
 import { appAtomRegistry } from "../../state/atom-registry";
@@ -165,16 +158,6 @@ function formatMessageTime(input: string): string {
   return MESSAGE_TIME_FORMATTER.format(timestamp);
 }
 
-// Pre-measurement heights for getFixedItemSize, mirroring renderFeedEntry's
-// classNames. The fold row's min-h-11 (44px) stays taller than its single
-// text-sm line at every supported base font size (26px at the 22pt maximum),
-// so its height is a constant; a drifted value costs one correction on
-// measure, not a persistent offset.
-const TURN_FOLD_HEIGHT = 56; // min-h-11 (44) + mb-3 (12)
-// The working row has no min-height clamp — its height follows the scaled
-// text-xs line height (see workingRowHeight in ThreadFeed).
-const WORKING_ROW_VERTICAL_EXTRAS = 24; // py-1 (8) + mb-4 (16)
-
 // Entering animations must only play for rows born just now — LegendList
 // remounts rows when they scroll back into view, and replaying an entrance for
 // old content would be its own kind of jank.
@@ -2244,34 +2227,13 @@ export const ThreadFeed = memo(function ThreadFeed(props: ThreadFeedProps) {
   // scrolling up through unmeasured content corrects each row's height as it
   // mounts — the feed visibly jumps. Fixed sizes make the small chrome rows
   // exact; message rows stay undefined and use LegendList's per-type running
-  // average once one of their type has been measured. Text-driven heights
-  // follow the configurable base font size via scaledTypographyLineHeight.
-  const workingRowHeight =
-    WORKING_ROW_VERTICAL_EXTRAS +
-    scaledTypographyLineHeight(MOBILE_TYPOGRAPHY.label, appearance.baseFontSize);
+  // average once one of their type has been measured. Activity groups are
+  // also content-driven: prominent v2 items add a card and related-thread
+  // link, so marking them fixed would make LegendList skip their measurement
+  // and position the next message inside the card.
   const getFixedItemSize = useCallback(
-    (entry: ThreadFeedEntry) => {
-      if (workRowSizing.fixedRowHeight === undefined) {
-        return undefined;
-      }
-      switch (entry.type) {
-        case "run-fold":
-          return TURN_FOLD_HEIGHT;
-        case "work-toggle":
-          return WORK_GROUP_TOGGLE_HEIGHT;
-        case "working":
-          return workingRowHeight;
-        case "activity-group":
-          // Expanded rows append a variable detail block — fall back to
-          // measurement for those groups.
-          return entry.activities.some((activity) => expandedWorkRows[activity.id])
-            ? undefined
-            : collapsedWorkLogHeight(entry.activities, appearance.baseFontSize);
-        default:
-          return undefined;
-      }
-    },
-    [expandedWorkRows, workingRowHeight, appearance.baseFontSize],
+    (entry: ThreadFeedEntry) => resolveThreadFeedFixedItemSize(entry.type, appearance.baseFontSize),
+    [appearance.baseFontSize],
   );
 
   // Disclosures can mount existing offscreen rows as well as new work rows.

apps/mobile/src/features/threads/thread-activity-row-presentation.test.ts

@@ -0,0 +1,42 @@
+import { ProviderDriverKind, ProviderInstanceId } from "@t3tools/contracts";
+import { describe, expect, it } from "vite-plus/test";
+
+import {
+  resolveThreadActivityMetadata,
+  resolveThreadActivityStatus,
+} from "./thread-activity-row-presentation";
+
+describe("thread activity row presentation", () => {
+  it("shows the provider and model as compact metadata", () => {
+    expect(
+      resolveThreadActivityMetadata({
+        providerDriver: ProviderDriverKind.make("codex"),
+        providerInstanceId: ProviderInstanceId.make("codex"),
+        model: "gpt-5.4",
+      }),
+    ).toBe("Codex · gpt-5.4");
+  });
+
+  it("falls back to the provider instance and removes duplicate metadata", () => {
+    expect(
+      resolveThreadActivityMetadata({
+        providerDriver: null,
+        providerInstanceId: ProviderInstanceId.make("custom-agent"),
+        model: "custom-agent",
+      }),
+    ).toBe("custom-agent");
+  });
+
+  it("maps lifecycle status to dot tone and an accessible label", () => {
+    expect(resolveThreadActivityStatus("running")).toEqual({ label: "Running", tone: "active" });
+    expect(resolveThreadActivityStatus("completed")).toEqual({
+      label: "Completed",
+      tone: "success",
+    });
+    expect(resolveThreadActivityStatus("failed")).toEqual({ label: "Failed", tone: "danger" });
+    expect(resolveThreadActivityStatus("interrupted")).toEqual({
+      label: "Interrupted",
+      tone: "warning",
+    });
+  });
+});

apps/mobile/src/features/threads/thread-activity-row-presentation.ts

@@ -0,0 +1,40 @@
+import {
+  PROVIDER_DISPLAY_NAMES,
+  type OrchestrationV2TurnItem,
+  type ProviderDriverKind,
+  type ProviderInstanceId,
+} from "@t3tools/contracts";
+
+export function resolveThreadActivityMetadata(input: {
+  readonly providerDriver: ProviderDriverKind | null;
+  readonly providerInstanceId: ProviderInstanceId | null;
+  readonly model: string | null;
+}): string {
+  const providerLabel = input.providerDriver
+    ? (PROVIDER_DISPLAY_NAMES[input.providerDriver] ?? input.providerInstanceId)
+    : input.providerInstanceId;
+  const values = [providerLabel, input.model].filter(
+    (value): value is string => value !== null && value.length > 0,
+  );
+  return [...new Set(values)].join(" · ");
+}
+
+export function resolveThreadActivityStatus(status: OrchestrationV2TurnItem["status"]): {
+  readonly label: string;
+  readonly tone: "active" | "danger" | "success" | "warning";
+} {
+  const label = status.charAt(0).toUpperCase() + status.slice(1).replaceAll("_", " ");
+  switch (status) {
+    case "completed":
+      return { label, tone: "success" };
+    case "failed":
+      return { label, tone: "danger" };
+    case "cancelled":
+    case "interrupted":
+      return { label, tone: "warning" };
+    case "pending":
+    case "running":
+    case "waiting":
+      return { label, tone: "active" };
+  }
+}

apps/mobile/src/features/threads/thread-feed-item-size.test.ts

@@ -0,0 +1,15 @@
+import { describe, expect, it } from "vite-plus/test";
+
+import { resolveThreadFeedFixedItemSize } from "./thread-feed-item-size";
+
+describe("resolveThreadFeedFixedItemSize", () => {
+  it("leaves activity groups to native measurement", () => {
+    expect(resolveThreadFeedFixedItemSize("activity-group", 16)).toBeUndefined();
+  });
+
+  it("keeps fixed timeline chrome on the premeasured path", () => {
+    expect(resolveThreadFeedFixedItemSize("run-fold", 16)).toBe(56);
+    expect(resolveThreadFeedFixedItemSize("work-toggle", 16)).toBe(36);
+    expect(resolveThreadFeedFixedItemSize("working", 16)).toBeGreaterThan(24);
+  });
+});

apps/mobile/src/features/threads/thread-feed-item-size.ts

@@ -0,0 +1,30 @@
+import type { ThreadFeedEntry } from "../../lib/threadActivity";
+import { scaledTypographyLineHeight } from "../../lib/appearancePreferences";
+import { MOBILE_TYPOGRAPHY } from "../../lib/typography";
+
+// These rows are pure timeline chrome whose rendered height is independent of
+// their content. Content-driven rows must be measured by LegendList: returning
+// a fixed size makes the list skip native measurement entirely.
+const TURN_FOLD_HEIGHT = 56;
+const WORK_GROUP_TOGGLE_HEIGHT = 36;
+const WORKING_ROW_VERTICAL_EXTRAS = 24;
+
+export function resolveThreadFeedFixedItemSize(
+  entryType: ThreadFeedEntry["type"],
+  baseFontSize: number,
+): number | undefined {
+  switch (entryType) {
+    case "run-fold":
+      return TURN_FOLD_HEIGHT;
+    case "work-toggle":
+      return WORK_GROUP_TOGGLE_HEIGHT;
+    case "working":
+      return (
+        WORKING_ROW_VERTICAL_EXTRAS +
+        scaledTypographyLineHeight(MOBILE_TYPOGRAPHY.label, baseFontSize)
+      );
+    case "activity-group":
+    case "message":
+      return undefined;
+  }
+}

apps/mobile/src/lib/threadActivity.test.ts

@@ -12,6 +12,7 @@ import { describe, expect, it } from "vite-plus/test";
 import {
   buildThreadFeed,
   deriveThreadFeedPresentation,
+  threadFeedActivityIsVisible,
   threadFeedRunIsUnsettled,
   type ThreadFeedActivity,
   type ThreadFeedEntry,
@@ -93,6 +94,15 @@ function assistantMessage(updatedAt = "2026-06-20T00:00:03.000Z") {
 }
 
 describe("buildThreadFeed", () => {
+  it("keeps prominent activity visible while it is running", () => {
+    expect(
+      threadFeedActivityIsVisible({ prominent: true, status: "neutral", toolLike: true }),
+    ).toBe(true);
+    expect(
+      threadFeedActivityIsVisible({ prominent: false, status: "neutral", toolLike: true }),
+    ).toBe(false);
+  });
+
   it("hides synthetic workspace preparation activity", () => {
     const workspacePreparation = projected(
       {

apps/mobile/src/lib/threadActivity.ts

@@ -475,6 +475,12 @@ export function threadFeedRunIsUnsettled(
   );
 }
 
+export function threadFeedActivityIsVisible(
+  activity: Pick<ThreadFeedActivity, "prominent" | "status" | "toolLike">,
+): boolean {
+  return activity.prominent || !(activity.toolLike && activity.status === "neutral");
+}
+
 interface ThreadFeedRunFold {
   readonly runId: RunId;
   readonly createdAt: string;
@@ -634,9 +640,7 @@ function appendPresentedFeedEntry(
     return;
   }
 
-  const activities = entry.activities.filter(
-    (activity) => !(activity.toolLike && activity.status === "neutral"),
-  );
+  const activities = entry.activities.filter(threadFeedActivityIsVisible);
   if (activities.length === 0) {
     return;
   }