From 8b9533c22a47bbf6f916667e2c25d8e8e419da37 Mon Sep 17 00:00:00 2001
From: Adam Malczewski <github@tradam.dev>
Date: Mon, 1 Jun 2026 01:46:13 +0900
Subject: feat(tabs): tab-to-tab agent communication via short handles

Add send_to_tab / read_tab tools so an agent can message or read another
tab by a git-style short handle (shortest unique prefix of the tab UUID,
min 4 chars), shown in the tab bar.

- core/db/tabs: resolveTabPrefix + shortestUniquePrefix (open tabs only,
  LIKE-sanitized prefix matching)
- new tools read-tab.ts / send-to-tab.ts (+ tests) decoupled from the DB
  TabRow via a minimal ResolvedTabRef projection
- agent-manager: unified deliverMessage routing (busy -> queue, idle ->
  new turn) shared by POST /chat and send_to_tab; agent->agent auto-wake
  budget (MAX_AGENT_AUTO_WAKES) to bound ping-pong loops
- summon/loader: send_to_tab + read_tab as grantable tools
- frontend: shortHandleFor + handle badge in TabBar; perm toggles
- notes: tab-comm / user-agents / todo-redesign plans
- chore: biome format fixes (debug-logger, summon.test)

Refs notes/plan-tab-comm.md
---
 packages/frontend/src/lib/components/TabBar.svelte          |  2 ++
 packages/frontend/src/lib/components/ToolPermissions.svelte | 10 ++++++++++
 2 files changed, 12 insertions(+)

(limited to 'packages/frontend/src/lib/components')

diff --git a/packages/frontend/src/lib/components/TabBar.svelte b/packages/frontend/src/lib/components/TabBar.svelte
index feb1e5b..3cbd849 100644
--- a/packages/frontend/src/lib/components/TabBar.svelte
+++ b/packages/frontend/src/lib/components/TabBar.svelte
@@ -56,6 +56,7 @@ const activeUserTabId = $derived(
 			>
 				<span class="flex items-center gap-1.5">
 					<span class="w-1.5 h-1.5 rounded-full shrink-0 {statusColor(tab.agentStatus)}"></span>
+					<span class="font-mono text-[10px] px-1 py-0.5 rounded bg-base-300 text-base-content/60 shrink-0" title="Tab ID — agents address this tab by this handle">{tabStore.shortHandleFor(tab.id)}</span>
 					<span class="max-w-32 truncate text-xs">{tab.title}</span>
 				</span>
 				<button
@@ -89,6 +90,7 @@ const activeUserTabId = $derived(
 				>
 					<span class="flex items-center gap-1">
 						<span class="w-1 h-1 rounded-full shrink-0 {statusColor(tab.agentStatus)}"></span>
+						<span class="font-mono text-[10px] px-1 rounded bg-base-300 text-base-content/60 shrink-0" title="Tab ID — agents address this tab by this handle">{tabStore.shortHandleFor(tab.id)}</span>
 						<span class="max-w-28 truncate text-xs">{tab.title}</span>
 					</span>
 					{#if tab.persistent}
diff --git a/packages/frontend/src/lib/components/ToolPermissions.svelte b/packages/frontend/src/lib/components/ToolPermissions.svelte
index d64eaf9..0caf0fa 100644
--- a/packages/frontend/src/lib/components/ToolPermissions.svelte
+++ b/packages/frontend/src/lib/components/ToolPermissions.svelte
@@ -27,6 +27,16 @@ const toolPermissions: ToolPermission[] = [
 		label: "Spawn user agents",
 		description: "Allow the AI to open new independent top-level tabs",
 	},
+	{
+		id: "send_to_tab",
+		label: "Message other tabs",
+		description: "Allow the AI to send messages to other tabs by their ID",
+	},
+	{
+		id: "read_tab",
+		label: "Read other tabs",
+		description: "Allow the AI to read other tabs' latest responses by their ID",
+	},
 	{
 		id: "web_search",
 		label: "Web search",
-- 
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