diff --git a/src/config/schema.rs b/src/config/schema.rs
index dee0e8f28..edd8f6aa8 100644
--- a/src/config/schema.rs
+++ b/src/config/schema.rs
@@ -6691,11 +6691,41 @@ impl Config {
         set_runtime_proxy_config(self.proxy.clone());
     }
 
-    pub async fn save(&self) -> Result<()> {
-        // Encrypt secrets before serialization
-        let mut config_to_save = self.clone();
-        let zeroclaw_dir = self
+    async fn resolve_config_path_for_save(&self) -> Result<PathBuf> {
+        if self
             .config_path
+            .parent()
+            .is_some_and(|parent| !parent.as_os_str().is_empty())
+        {
+            return Ok(self.config_path.clone());
+        }
+
+        let (default_zeroclaw_dir, default_workspace_dir) = default_config_and_workspace_dirs()?;
+        let (zeroclaw_dir, _workspace_dir, source) =
+            resolve_runtime_config_dirs(&default_zeroclaw_dir, &default_workspace_dir).await?;
+        let file_name = self
+            .config_path
+            .file_name()
+            .filter(|name| !name.is_empty())
+            .unwrap_or_else(|| std::ffi::OsStr::new("config.toml"));
+        let resolved = zeroclaw_dir.join(file_name);
+        tracing::warn!(
+            path = %self.config_path.display(),
+            resolved = %resolved.display(),
+            source = source.as_str(),
+            "Config path missing parent directory; resolving from runtime environment"
+        );
+        Ok(resolved)
+    }
+
+    pub async fn save(&mut self) -> Result<()> {
+        // Encrypt secrets before serialization
+        let config_path = self.resolve_config_path_for_save().await?;
+        // Keep the in-memory config_path in sync so downstream reads
+        // (e.g. proxy_config, model_routing_config) use the resolved path.
+        self.config_path = config_path.clone();
+        let mut config_to_save = self.clone();
+        let zeroclaw_dir = config_path
             .parent()
             .context("Config path must have a parent directory")?;
         let store = crate::security::SecretStore::new(zeroclaw_dir, self.secrets.encrypt);
@@ -6764,8 +6794,7 @@ impl Config {
         let toml_str =
             toml::to_string_pretty(&config_to_save).context("Failed to serialize config")?;
 
-        let parent_dir = self
-            .config_path
+        let parent_dir = config_path
             .parent()
             .context("Config path must have a parent directory")?;
 
@@ -6776,8 +6805,7 @@ impl Config {
             )
         })?;
 
-        let file_name = self
-            .config_path
+        let file_name = config_path
             .file_name()
             .and_then(|v| v.to_str())
             .unwrap_or("config.toml");
@@ -6817,9 +6845,9 @@ impl Config {
             .context("Failed to fsync temporary config file")?;
         drop(temp_file);
 
-        let had_existing_config = self.config_path.exists();
+        let had_existing_config = config_path.exists();
         if had_existing_config {
-            fs::copy(&self.config_path, &backup_path)
+            fs::copy(&config_path, &backup_path)
                 .await
                 .with_context(|| {
                     format!(
@@ -6829,10 +6857,10 @@ impl Config {
                 })?;
         }
 
-        if let Err(e) = fs::rename(&temp_path, &self.config_path).await {
+        if let Err(e) = fs::rename(&temp_path, &config_path).await {
             let _ = fs::remove_file(&temp_path).await;
             if had_existing_config && backup_path.exists() {
-                fs::copy(&backup_path, &self.config_path)
+                fs::copy(&backup_path, &config_path)
                     .await
                     .context("Failed to restore config backup")?;
             }
@@ -6842,12 +6870,12 @@ impl Config {
         #[cfg(unix)]
         {
             use std::{fs::Permissions, os::unix::fs::PermissionsExt};
-            fs::set_permissions(&self.config_path, Permissions::from_mode(0o600))
+            fs::set_permissions(&config_path, Permissions::from_mode(0o600))
                 .await
                 .with_context(|| {
                     format!(
                         "Failed to enforce secure permissions on config file: {}",
-                        self.config_path.display()
+                        config_path.display()
                     )
                 })?;
         }
@@ -7660,7 +7688,7 @@ tool_dispatcher = "xml"
         fs::create_dir_all(&dir).await.unwrap();
 
         let config_path = dir.join("config.toml");
-        let config = Config {
+        let mut config = Config {
             workspace_dir: dir.join("workspace"),
             config_path: config_path.clone(),
             api_key: Some("sk-roundtrip".into()),
@@ -10486,6 +10514,44 @@ default_model = "legacy-model"
         );
     }
 
+    #[test]
+    async fn save_repairs_bare_config_filename_using_runtime_resolution() {
+        let _env_guard = env_override_lock().await;
+        let temp_home =
+            std::env::temp_dir().join(format!("zeroclaw_test_home_{}", uuid::Uuid::new_v4()));
+        let workspace_dir = temp_home.join("workspace");
+        let resolved_config_path = temp_home.join(".zeroclaw").join("config.toml");
+
+        let original_home = std::env::var("HOME").ok();
+        std::env::set_var("HOME", &temp_home);
+        std::env::set_var("ZEROCLAW_WORKSPACE", &workspace_dir);
+
+        let mut config = Config::default();
+        config.workspace_dir = workspace_dir;
+        config.config_path = PathBuf::from("config.toml");
+        config.default_temperature = 0.5;
+        config.save().await.unwrap();
+
+        assert!(resolved_config_path.exists());
+        assert_eq!(
+            config.config_path, resolved_config_path,
+            "save() must update config_path to the resolved path"
+        );
+        let saved = tokio::fs::read_to_string(&resolved_config_path)
+            .await
+            .unwrap();
+        let parsed: Config = toml::from_str(&saved).unwrap();
+        assert_eq!(parsed.default_temperature, 0.5);
+
+        std::env::remove_var("ZEROCLAW_WORKSPACE");
+        if let Some(home) = original_home {
+            std::env::set_var("HOME", home);
+        } else {
+            std::env::remove_var("HOME");
+        }
+        let _ = tokio::fs::remove_dir_all(temp_home).await;
+    }
+
     #[cfg(unix)]
     #[test]
     async fn save_restricts_existing_world_readable_config_to_owner_only() {
diff --git a/src/gateway/api.rs b/src/gateway/api.rs
index 13da1c5e2..a13a59ae9 100644
--- a/src/gateway/api.rs
+++ b/src/gateway/api.rs
@@ -543,7 +543,7 @@ pub async fn handle_api_config_put(
     };
 
     let current_config = state.config.lock().clone();
-    let new_config = hydrate_config_for_save(incoming, &current_config);
+    let mut new_config = hydrate_config_for_save(incoming, &current_config);
 
     if let Err(e) = new_config.validate() {
         return (
@@ -752,7 +752,7 @@ pub async fn handle_api_integration_credentials_put(
         }
     }
 
-    let updated = match apply_integration_credentials_update(&current, &id, &body.fields) {
+    let mut updated = match apply_integration_credentials_update(&current, &id, &body.fields) {
         Ok(config) => config,
         Err(error) if error.starts_with("Unknown integration id:") => {
             return (
diff --git a/src/onboard/wizard.rs b/src/onboard/wizard.rs
index 159cd3aec..eccfde9d2 100644
--- a/src/onboard/wizard.rs
+++ b/src/onboard/wizard.rs
@@ -128,7 +128,7 @@ pub async fn run_wizard(force: bool) -> Result<Config> {
 
     // ── Build config ──
     // Defaults: SQLite memory, supervised autonomy, workspace-scoped, native runtime
-    let config = Config {
+    let mut config = Config {
         workspace_dir: workspace_dir.clone(),
         config_path: config_path.clone(),
         api_key: if api_key.is_empty() {
@@ -487,7 +487,7 @@ async fn run_quick_setup_with_home(
     // Create memory config based on backend choice
     let memory_config = memory_config_defaults_for_backend(&memory_backend_name);
 
-    let config = Config {
+    let mut config = Config {
         workspace_dir: workspace_dir.clone(),
         config_path: config_path.clone(),
         api_key: credential_override.map(|c| {
diff --git a/src/tools/model_routing_config.rs b/src/tools/model_routing_config.rs
index 1eaf7bb94..3adec24cc 100644
--- a/src/tools/model_routing_config.rs
+++ b/src/tools/model_routing_config.rs
@@ -921,7 +921,7 @@ mod tests {
     }
 
     async fn test_config(tmp: &TempDir) -> Arc<Config> {
-        let config = Config {
+        let mut config = Config {
             workspace_dir: tmp.path().join("workspace"),
             config_path: tmp.path().join("config.toml"),
             ..Config::default()
diff --git a/src/tools/proxy_config.rs b/src/tools/proxy_config.rs
index 213a57e0c..f58beed20 100644
--- a/src/tools/proxy_config.rs
+++ b/src/tools/proxy_config.rs
@@ -450,7 +450,7 @@ mod tests {
     }
 
     async fn test_config(tmp: &TempDir) -> Arc<Config> {
-        let config = Config {
+        let mut config = Config {
             workspace_dir: tmp.path().join("workspace"),
             config_path: tmp.path().join("config.toml"),
             ..Config::default()