feat(sidebar-tabs): click tab ID badge to copy conversation id

2 files changed, 88 insertions, 6 deletions

diff --git a/src/features/tabs/ui.test.ts b/src/features/tabs/ui.test.ts
index ff342d0..57f9bc1 100644
--- a/src/features/tabs/ui.test.ts
+++ b/src/features/tabs/ui.test.ts
@@ -1,4 +1,4 @@
-import { render, screen } from "@testing-library/svelte";
+import { fireEvent, render, screen } from "@testing-library/svelte";
 import userEvent from "@testing-library/user-event";
 import { describe, expect, it, vi } from "vitest";
 import type { Tab } from "./tabs";
@@ -229,4 +229,34 @@ describe("TabList", () => {
     expect(onRename).toHaveBeenCalledTimes(1);
     expect(onRename).toHaveBeenCalledWith("c1", "Renamed");
   });
+
+  it("copies the full conversation id to the clipboard and shows 'Copied!' when the ID badge is clicked", async () => {
+    const writeText = vi.fn().mockResolvedValue(undefined);
+    Object.defineProperty(navigator, "clipboard", {
+      value: { writeText },
+      configurable: true,
+    });
+
+    const onSelect = vi.fn();
+
+    render(TabList, {
+      props: {
+        tabs: sampleTabs,
+        activeConversationId: "c1",
+        onSelect,
+        onClose: vi.fn(),
+        onNewDraft: vi.fn(),
+      },
+    });
+
+    const idBadge = screen.getByRole("button", { name: "Copy conversation id c1" });
+    await fireEvent.click(idBadge);
+
+    expect(writeText).toHaveBeenCalledTimes(1);
+    expect(writeText).toHaveBeenCalledWith("c1");
+    // The badge briefly shows a "Copied!" confirmation.
+    expect(idBadge).toHaveTextContent("Copied!");
+    // Clicking the ID must NOT switch tabs (the badge stops propagation).
+    expect(onSelect).not.toHaveBeenCalled();
+  });
 });
diff --git a/src/features/tabs/ui/TabList.svelte b/src/features/tabs/ui/TabList.svelte
index efef4fa..40f95cd 100644
--- a/src/features/tabs/ui/TabList.svelte
+++ b/src/features/tabs/ui/TabList.svelte
@@ -55,6 +55,46 @@
 	function cancelRename(): void {
 		editingId = null;
 	}
+
+	// Click-to-copy the agent (conversation) id: clicking the ID badge copies the
+	// FULL conversationId to the clipboard (the stable, useful id — the badge
+	// only shows a short prefix) and briefly highlights the badge as feedback.
+	// Clipboard is the edge effect; absent (insecure context) → select the badge
+	// text so the user can Ctrl+C manually.
+	let copiedId = $state<string | null>(null);
+	let copyTimer: ReturnType<typeof setTimeout> | undefined;
+
+	async function copyId(conversationId: string, el: HTMLElement): Promise<void> {
+		const clipboard = navigator.clipboard;
+		if (clipboard === undefined) {
+			selectText(el);
+			flashCopied(conversationId);
+			return;
+		}
+		try {
+			await clipboard.writeText(conversationId);
+			flashCopied(conversationId);
+		} catch {
+			selectText(el);
+			flashCopied(conversationId);
+		}
+	}
+
+	function flashCopied(conversationId: string): void {
+		copiedId = conversationId;
+		clearTimeout(copyTimer);
+		copyTimer = setTimeout(() => {
+			copiedId = null;
+		}, 1200);
+	}
+
+	function selectText(el: HTMLElement): void {
+		const range = document.createRange();
+		range.selectNodeContents(el);
+		const selection = window.getSelection();
+		selection?.removeAllRanges();
+		selection?.addRange(range);
+	}
 </script>
 
 <div class="flex flex-col gap-2">
@@ -75,12 +115,24 @@
 					if (e.key === "Enter") onSelect(tab.conversationId);
 				}}
 			>
-				<span
-					class="shrink-0 rounded bg-base-300 px-1 py-0.5 font-mono text-[10px] leading-none text-base-content/60"
-					title="Tab ID"
+				<button
+					type="button"
+					class="shrink-0 rounded px-1 py-0.5 font-mono text-[10px] leading-none transition-colors {copiedId ===
+					tab.conversationId
+						? "bg-success text-success-content"
+						: "bg-base-300 text-base-content/60 hover:bg-primary hover:text-primary-content"}"
+					data-copy-id={tab.conversationId}
+					title={copiedId === tab.conversationId ? "Copied!" : "Click to copy conversation id"}
+					aria-label={`Copy conversation id ${tab.conversationId}`}
+					onclick={(e) => {
+						e.stopPropagation();
+						void copyId(tab.conversationId, e.currentTarget);
+					}}
 				>
-					{handles.get(tab.conversationId) ?? tab.conversationId}
-				</span>
+					{copiedId === tab.conversationId
+						? "Copied!"
+						: (handles.get(tab.conversationId) ?? tab.conversationId)}
+				</button>
 				{#if editingId === tab.conversationId}
 					<input
 						bind:this={editEl}