From 4b730a887523cd489fcd587c4658c0905db44dc2 Mon Sep 17 00:00:00 2001
From: Agile Agents <agile-agents@local>
Date: Wed, 9 Sep 2026 22:08:55 +0800
Subject: [PATCH] agile(issue-71): implement ticket

---
 acceptance/routing/duration.ts | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/acceptance/routing/duration.ts b/acceptance/routing/duration.ts
index e57eb6f..00c9c56 100644
--- a/acceptance/routing/duration.ts
+++ b/acceptance/routing/duration.ts
@@ -1,4 +1,20 @@
 /** Formats elapsed milliseconds for a task display. */
-export function formatDuration(_milliseconds: number | null): string {
-  throw new Error("Not implemented");
+export function formatDuration(milliseconds: number | null): string {
+  if (milliseconds === null || !Number.isFinite(milliseconds)) {
+    return "Unavailable";
+  }
+
+  const seconds = Math.floor(Math.max(0, milliseconds) / 1000);
+  if (seconds < 60) {
+    return `${seconds}s`;
+  }
+
+  const minutes = Math.floor(seconds / 60);
+  const remainingSeconds = seconds % 60;
+  if (seconds < 3600) {
+    return `${minutes}m ${remainingSeconds}s`;
+  }
+
+  const hours = Math.floor(minutes / 60);
+  return `${hours}h ${minutes % 60}m ${remainingSeconds}s`;
 }