diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2f7b784707..aab6d93f5e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,14 @@
 # Changelog
 
+## [0.13.4.1] - 2026-03-29 — Sidebar Agent Action Expansion
+
+The Chrome sidebar agent can now write files, enabling full IDE assistance directly from the side panel.
+
+### Fixed
+
+- **Sidebar Agent Tool Restrictions.** Added `Write` to the sidebar agent's allowed tools, fixing a bug where it couldn't operate on local files.
+- **Empty State UX.** Prevented the agent output container from hanging silently when no textual response is produced; it now displays a clear "Claude finished but produced no output" message.
+
 ## [0.13.4.0] - 2026-03-29 — Sidebar Defense
 
 The Chrome sidebar now defends against prompt injection attacks. Three layers: XML-framed prompts with trust boundaries, a command allowlist that restricts bash to browse commands only, and Opus as the default model (harder to manipulate).
diff --git a/VERSION b/VERSION
index 3bfa77a455..c1333dd6e6 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.13.4.0
+0.13.4.1
diff --git a/browse/src/server.ts b/browse/src/server.ts
index f3f8d68dd8..05684f661e 100644
--- a/browse/src/server.ts
+++ b/browse/src/server.ts
@@ -430,7 +430,7 @@ function spawnClaude(userMessage: string, extensionUrl?: string | null): void {
 
   const prompt = `${systemPrompt}\n\n<user-message>\n${escapedMessage}\n</user-message>`;
   const args = ['-p', prompt, '--model', 'opus', '--output-format', 'stream-json', '--verbose',
-    '--allowedTools', 'Bash,Read,Glob,Grep'];
+    '--allowedTools', 'Bash,Read,Write,Glob,Grep'];
   if (sidebarSession?.claudeSessionId) {
     args.push('--resume', sidebarSession.claudeSessionId);
   }
diff --git a/browse/src/sidebar-agent.ts b/browse/src/sidebar-agent.ts
index db56022114..6d8c185a96 100644
--- a/browse/src/sidebar-agent.ts
+++ b/browse/src/sidebar-agent.ts
@@ -162,7 +162,7 @@ async function askClaude(queueEntry: any): Promise<void> {
     // Use args from queue entry (server sets --model, --allowedTools, prompt framing).
     // Fall back to defaults only if queue entry has no args (backward compat).
     let claudeArgs = args || ['-p', prompt, '--output-format', 'stream-json', '--verbose',
-      '--allowedTools', 'Bash,Read,Glob,Grep'];
+      '--allowedTools', 'Bash,Read,Write,Glob,Grep'];
 
     // Validate cwd exists — queue may reference a stale worktree
     let effectiveCwd = cwd || process.cwd();
diff --git a/browse/test/sidebar-security.test.ts b/browse/test/sidebar-security.test.ts
index b953f5b770..2e0617524f 100644
--- a/browse/test/sidebar-security.test.ts
+++ b/browse/test/sidebar-security.test.ts
@@ -115,6 +115,6 @@ describe('Sidebar prompt injection defense', () => {
 
   test('sidebar-agent falls back to defaults if queue has no args', () => {
     // Backward compatibility: if old queue entries lack args, use defaults
-    expect(AGENT_SRC).toContain("'--allowedTools', 'Bash,Read,Glob,Grep'");
+    expect(AGENT_SRC).toContain("'--allowedTools', 'Bash,Read,Write,Glob,Grep'");
   });
 });
diff --git a/extension/sidepanel.css b/extension/sidepanel.css
index 855589616e..db46ca4bdf 100644
--- a/extension/sidepanel.css
+++ b/extension/sidepanel.css
@@ -305,6 +305,12 @@ body::after {
   font-size: 12px;
   font-family: var(--font-mono);
 }
+.agent-empty {
+  color: var(--text-label);
+  font-style: italic;
+  font-size: 11px;
+  padding: 4px 0;
+}
 
 /* Thinking dots animation */
 .agent-thinking {
diff --git a/extension/sidepanel.js b/extension/sidepanel.js
index 2ee3da6b3b..e95f3b8a7e 100644
--- a/extension/sidepanel.js
+++ b/extension/sidepanel.js
@@ -157,6 +157,13 @@ function handleAgentEvent(entry) {
     // Remove thinking indicator
     const thinking = document.getElementById('agent-thinking');
     if (thinking) thinking.remove();
+    // If agent finished with no text output, show a "no output" message
+    if (agentContainer && !agentTextEl) {
+      const empty = document.createElement('div');
+      empty.className = 'agent-empty';
+      empty.textContent = 'Claude finished but produced no output.';
+      agentContainer.appendChild(empty);
+    }
     // Add timestamp
     if (agentContainer) {
       const ts = document.createElement('span');
diff --git a/package.json b/package.json
index 55f7a9fbbe..d994803fcf 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "gstack",
-  "version": "0.13.3.0",
+  "version": "0.13.4.1",
   "description": "Garry's Stack — Claude Code skills + fast headless browser. One repo, one install, entire AI engineering workflow.",
   "license": "MIT",
   "type": "module",