diff --git a/CHANGELOG.md b/CHANGELOG.md
index 256034e4..5ced0950 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # aicodeman
 
+## 0.6.4
+
+### Patch Changes
+
+- Fix "Failed to enable respawn: Invalid request body" error when selecting infinity duration (∞) in the respawn modal. Frontend was sending `durationMinutes: null`, which Zod's `.optional()` schema rejected (it accepts `undefined` only). The body now omits the field when no duration is selected.
+
 ## 0.6.3
 
 ### Patch Changes
diff --git a/CLAUDE.md b/CLAUDE.md
index 67b6a425..3d175394 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -55,7 +55,7 @@ When user says "COM":
 
 CI runs `npm run check:lockfile` on every push/PR, so lockfile drift fails the build even if the `version-packages` script is bypassed.
 
-**Version**: 0.6.3 (must match `package.json`)
+**Version**: 0.6.4 (must match `package.json`)
 
 ## Project Overview
 
diff --git a/package-lock.json b/package-lock.json
index 26372601..bbb225d9 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "aicodeman",
-  "version": "0.6.3",
+  "version": "0.6.4",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "aicodeman",
-      "version": "0.6.3",
+      "version": "0.6.4",
       "hasInstallScript": true,
       "license": "MIT",
       "workspaces": [
diff --git a/package.json b/package.json
index 78564b52..9dd7f4dd 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "aicodeman",
-  "version": "0.6.3",
+  "version": "0.6.4",
   "description": "The missing control plane for AI coding agents - run 20 autonomous agents with real-time monitoring and session persistence",
   "type": "module",
   "main": "dist/index.js",
diff --git a/src/web/public/respawn-ui.js b/src/web/public/respawn-ui.js
index 05179b54..8e605742 100644
--- a/src/web/public/respawn-ui.js
+++ b/src/web/public/respawn-ui.js
@@ -792,7 +792,7 @@ Object.assign(CodemanApp.prototype, {
       const res = await fetch(`/api/sessions/${this.editingSessionId}/respawn/enable`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
-        body: JSON.stringify({ config: respawnConfig, durationMinutes })
+        body: JSON.stringify({ config: respawnConfig, durationMinutes: durationMinutes ?? undefined })
       });
       const data = await res.json();
       if (data.error) throw new Error(data.error);