diff --git a/packages/cli/src/commands/history.ts b/packages/cli/src/commands/history.ts
index e0e0c24c7af..64991bdacc8 100644
--- a/packages/cli/src/commands/history.ts
+++ b/packages/cli/src/commands/history.ts
@@ -26,6 +26,7 @@ import {
   type Turn,
   type UndoMode,
 } from "../utils/historyOwner.js";
+import { ago } from "../utils/historyAgo.js";
 import { AmbiguousPreviewServerError } from "../utils/studioSelectionClient.js";
 import { withMeta } from "../utils/updateCheck.js";
 
@@ -103,20 +104,12 @@ function since(entries: HistoryListItem[], ref: string, who: HistoryWho): Histor
   return entries.slice(entries.indexOf(entryOf(entries, ref)) + 1);
 }
 
-function ago(at: number): string {
-  const seconds = Math.max(0, Math.round((historyDeps.now() - at) / 1000));
-  if (seconds < 60) return `${seconds}s ago`;
-  if (seconds < 3600) return `${Math.round(seconds / 60)}m ago`;
-  if (seconds < 86_400) return `${Math.round(seconds / 3600)}h ago`;
-  return `${Math.round(seconds / 86_400)}d ago`;
-}
-
 function line(entry: HistoryListItem | HistoryEntry): string {
   const paths = entry.files.map((file) => file.path);
   const files = paths.slice(0, 2).join(", ") + (paths.length > 2 ? ` +${paths.length - 2}` : "");
   const flags =
     "undone" in entry ? `${entry.undone ? " [undone]" : ""}${entry.pinned ? " [pinned]" : ""}` : "";
-  return `${short(entry.id)}  ${ago(entry.endedAt)}  ${entry.who.name}  ${entry.label}  (${files})${flags}`;
+  return `${short(entry.id)}  ${ago(entry.endedAt, historyDeps.now())}  ${entry.who.name}  ${entry.label}  (${files})${flags}`;
 }
 
 /** The public entry shape: files as paths, no hashes. */
diff --git a/packages/cli/src/utils/historyAgo.test.ts b/packages/cli/src/utils/historyAgo.test.ts
new file mode 100644
index 00000000000..9daf5bb842b
--- /dev/null
+++ b/packages/cli/src/utils/historyAgo.test.ts
@@ -0,0 +1,24 @@
+import { describe, expect, it } from "vitest";
+import { ago } from "./historyAgo.js";
+
+describe("ago", () => {
+  const at = 1_000_000_000_000;
+  const after = (seconds: number) => ago(at, at + seconds * 1000);
+
+  it("counts whole seconds, minutes, hours and days", () => {
+    expect(after(0)).toBe("0s ago");
+    expect(after(59)).toBe("59s ago");
+    expect(after(3600)).toBe("1h ago");
+    expect(after(86_400)).toBe("1d ago");
+    expect(after(3 * 86_400)).toBe("3d ago");
+  });
+
+  it("never prints a unit at the size of the next one", () => {
+    expect(after(3570)).toBe("59m ago");
+    expect(after(86_000)).toBe("23h ago");
+  });
+
+  it("treats a future timestamp as now", () => {
+    expect(ago(at + 5000, at)).toBe("0s ago");
+  });
+});
diff --git a/packages/cli/src/utils/historyAgo.ts b/packages/cli/src/utils/historyAgo.ts
new file mode 100644
index 00000000000..edf4e0f938a
--- /dev/null
+++ b/packages/cli/src/utils/historyAgo.ts
@@ -0,0 +1,8 @@
+// Floor each larger unit: rounding would print "60m ago" at 59.5 minutes and "24h ago" at 23.5 hours.
+export function ago(at: number, now: number): string {
+  const seconds = Math.max(0, Math.round((now - at) / 1000));
+  if (seconds < 60) return `${seconds}s ago`;
+  if (seconds < 3600) return `${Math.floor(seconds / 60)}m ago`;
+  if (seconds < 86_400) return `${Math.floor(seconds / 3600)}h ago`;
+  return `${Math.floor(seconds / 86_400)}d ago`;
+}