diff --git a/crates/zesdex-cms/src/domain/settings.rs b/crates/zesdex-cms/src/domain/settings.rs
index bbff95c..71add9e 100644
--- a/crates/zesdex-cms/src/domain/settings.rs
+++ b/crates/zesdex-cms/src/domain/settings.rs
@@ -44,6 +44,10 @@ impl Default for SettingsFlags {
     }
 }
 
+fn default_hive_mind_node_timeout_ms() -> u64 {
+    600_000
+}
+
 /// Top-level application settings.
 ///
 /// Serialized to `settings.json` by the infrastructure layer.
@@ -63,6 +67,7 @@ pub struct Settings {
     #[serde(flatten)]
     pub flags: SettingsFlags,
     pub lsp_languages: Vec<String>,
+    #[serde(default = "default_hive_mind_node_timeout_ms")]
     pub hive_mind_node_timeout_ms: u64,
 }
 
diff --git a/crates/zesdex-cms/src/infrastructure/persistence/settings_repo.rs b/crates/zesdex-cms/src/infrastructure/persistence/settings_repo.rs
index 7a833b6..400931a 100644
--- a/crates/zesdex-cms/src/infrastructure/persistence/settings_repo.rs
+++ b/crates/zesdex-cms/src/infrastructure/persistence/settings_repo.rs
@@ -34,8 +34,16 @@ impl SettingsRepository for JsonSettingsRepository {
     fn load(&self, base_dir: &Path) -> Result<Settings> {
         let path = base_dir.join("settings.json");
         match std::fs::read_to_string(&path) {
-            Ok(s) => serde_json::from_str(&s)
-                .map_err(|e| anyhow::anyhow!("failed to parse settings.json: {e}")),
+            Ok(s) => match serde_json::from_str(&s) {
+                Ok(settings) => Ok(settings),
+                Err(e) => {
+                    tracing::warn!(
+                        "settings.json at '{}' failed to parse ({e}); falling back to defaults",
+                        path.display()
+                    );
+                    Ok(Settings::default())
+                }
+            },
             Err(e) if e.kind() == std::io::ErrorKind::NotFound => {
                 tracing::info!("settings.json not found, using defaults");
                 Ok(Settings::default())
@@ -72,3 +80,25 @@ impl SettingsRepository for JsonSettingsRepository {
         Ok(())
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn load_defaults_hive_mind_timeout_when_field_missing_from_old_settings_json() {
+        let dir = std::env::temp_dir().join(format!("zesdex-cms-settings-test-{}", uuid::Uuid::new_v4()));
+        std::fs::create_dir_all(&dir).unwrap();
+        // Simulate a settings.json written before `hive_mind_node_timeout_ms` existed.
+        std::fs::write(
+            dir.join("settings.json"),
+            r#"{"internet_mode":"Off","provider":"zen","model":"m","api_keys":{},"max_tokens":null,"temperature":null,"review_max_lessons_per_run":5,"adaptive_review_max_skip":3,"verify_command":null,"verify_timeout_ms":30000,"workflow_max_concurrency":5,"review_enabled":true,"session_archive_enabled":true,"lsp_auto_provision":true,"lsp_languages":[]}"#,
+        ).unwrap();
+
+        let repo = JsonSettingsRepository::new();
+        let settings = repo.load(&dir).expect("load must not fail on a pre-existing settings.json missing the new field");
+        assert_eq!(settings.hive_mind_node_timeout_ms, 600_000);
+
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+}