diff --git a/src-tauri/src/config/model.rs b/src-tauri/src/config/model.rs
index ab9057d..15be9b6 100644
--- a/src-tauri/src/config/model.rs
+++ b/src-tauri/src/config/model.rs
@@ -78,7 +78,10 @@ impl Default for AppConfig {
             pr_cooldown_seconds: 1800,
             source_kind: SourceKind::default(),
             engine_kind: EngineKind::default(),
-            auto_review: true,
+            // Boot defaults to manual review: scheduler polls/emits but does NOT
+            // auto-dispatch codex at startup (avoids clashing with other review
+            // processes). Flip-back guarded by `default_auto_review_is_off`.
+            auto_review: false,
             webhook_enabled: false,
             webhook_port: 8787,
             webhook_secret: String::new(),
@@ -245,7 +248,7 @@ mod tests {
             pr_cooldown_seconds: 1800,
             source_kind: SourceKind::default(),
             engine_kind: EngineKind::default(),
-            auto_review: true,
+            auto_review: false,
             webhook_enabled: false,
             webhook_port: 8787,
             webhook_secret: "shh".to_string(),
@@ -310,6 +313,17 @@ mod tests {
         assert_eq!(AppConfig::default().repo_root, "");
     }
 
+    /// Default-manual-review lock (Medium). A fresh/reset config must NOT
+    /// auto-dispatch codex review at boot: `auto_review` defaults off, so the
+    /// scheduler only polls/emits PRs and codex is left to the explicit triggers
+    /// (`start_review` / `start_codex`). Locking the default here makes that intent
+    /// machine-checked — a silent flip back to `true` would reintroduce the
+    /// boot-time review-process clash this guards against, and fails CI first.
+    #[test]
+    fn default_auto_review_is_off() {
+        assert!(!AppConfig::default().auto_review);
+    }
+
     #[test]
     fn validate_accepts_existing_repo_root_and_skill() {
         let config = AppConfig {
diff --git a/src/config/OnboardingWizard.vue b/src/config/OnboardingWizard.vue
index 06647c7..2f2586c 100644
--- a/src/config/OnboardingWizard.vue
+++ b/src/config/OnboardingWizard.vue
@@ -34,7 +34,7 @@ const draft = reactive<AppConfig>({
   prCooldownSeconds: 0,
   sourceKind: "github",
   engineKind: "codex",
-  autoReview: true,
+  autoReview: false,
   webhookEnabled: false,
   webhookPort: 8787,
   webhookSecret: "",
diff --git a/src/config/SettingsView.vue b/src/config/SettingsView.vue
index f8ae0a4..1a1ea66 100644
--- a/src/config/SettingsView.vue
+++ b/src/config/SettingsView.vue
@@ -33,7 +33,7 @@ const draft = reactive<AppConfig>({
   prCooldownSeconds: 0,
   sourceKind: "github",
   engineKind: "codex",
-  autoReview: true,
+  autoReview: false,
   webhookEnabled: false,
   webhookPort: 8787,
   webhookSecret: "",
diff --git a/src/config/fields.test.ts b/src/config/fields.test.ts
index 8e6a95e..a4e8b01 100644
--- a/src/config/fields.test.ts
+++ b/src/config/fields.test.ts
@@ -25,7 +25,7 @@ function validDraft(): AppConfig {
     prCooldownSeconds: 1800,
     sourceKind: "github",
     engineKind: "codex",
-    autoReview: true,
+    autoReview: false,
     webhookEnabled: false,
     webhookPort: 8787,
     webhookSecret: "",
diff --git a/src/config/useConfigStore.test.ts b/src/config/useConfigStore.test.ts
index f3f1301..dc70ade 100644
--- a/src/config/useConfigStore.test.ts
+++ b/src/config/useConfigStore.test.ts
@@ -25,7 +25,7 @@ const cfg = (over: Partial<AppConfig> = {}): AppConfig => ({
   prCooldownSeconds: 1800,
   sourceKind: "github",
   engineKind: "codex",
-  autoReview: true,
+  autoReview: false,
   webhookEnabled: false,
   webhookPort: 8787,
   webhookSecret: "",