diff --git a/codex-rs/core/src/session/mod.rs b/codex-rs/core/src/session/mod.rs
index 49889b2052..c785ea9b88 100644
--- a/codex-rs/core/src/session/mod.rs
+++ b/codex-rs/core/src/session/mod.rs
@@ -442,7 +442,7 @@ impl Codex {
 
     async fn spawn_internal(args: CodexSpawnArgs) -> CodexResult<CodexSpawnOk> {
         let CodexSpawnArgs {
-            config,
+            mut config,
             auth_manager,
             models_manager,
             environment_manager,
diff --git a/codex-rs/core/src/session/session.rs b/codex-rs/core/src/session/session.rs
index be2104f161..8001670315 100644
--- a/codex-rs/core/src/session/session.rs
+++ b/codex-rs/core/src/session/session.rs
@@ -208,13 +208,6 @@ impl SessionConfiguration {
 
         let cwd_changed = absolute_cwd.as_path() != self.cwd.as_path();
         next_configuration.cwd = absolute_cwd.clone();
-        if updates.environments.is_none()
-            && cwd_changed
-            && next_configuration.environments.len() == 1
-            && let Some(turn_environment) = next_configuration.environments.first_mut()
-        {
-            turn_environment.cwd = absolute_cwd;
-        }
 
         if let Some(permission_profile) = updates.permission_profile.clone() {
             let active_permission_profile =
@@ -915,6 +908,7 @@ impl Session {
                 .map(|(name, _)| name.clone())
                 .collect();
             required_mcp_servers.sort();
+            let enabled_mcp_server_count = mcp_servers.values().filter(|server| server.enabled).count();
             let required_mcp_server_count = required_mcp_servers.len();
             let tool_plugin_provenance = mcp_manager.tool_plugin_provenance(config.as_ref()).await;
             {
diff --git a/codex-rs/core/src/session/tests.rs b/codex-rs/core/src/session/tests.rs
index 2ffc1ddc94..c1c02886f6 100644
--- a/codex-rs/core/src/session/tests.rs
+++ b/codex-rs/core/src/session/tests.rs
@@ -3330,6 +3330,38 @@ async fn relative_cwd_update_without_environments_resolves_under_session_cwd() {
     assert!(state.session_configuration.environments.is_empty());
 }
 
+#[tokio::test]
+async fn cwd_update_does_not_rewrite_sticky_environment_cwd() {
+    let (session, _turn_context) = make_session_and_context().await;
+    let (original_cwd, environment_cwd) = {
+        let mut state = session.state.lock().await;
+        let original_cwd = state.session_configuration.cwd.clone();
+        let environment_cwd = original_cwd.join("environment");
+        state.session_configuration.environments = vec![TurnEnvironmentSelection {
+            environment_id: codex_exec_server::LOCAL_ENVIRONMENT_ID.to_string(),
+            cwd: environment_cwd.clone(),
+        }];
+        (original_cwd, environment_cwd)
+    };
+    let updated_cwd = original_cwd.join("project");
+    std::fs::create_dir_all(updated_cwd.as_path()).expect("create project dir");
+
+    session
+        .update_settings(SessionSettingsUpdate {
+            cwd: Some(PathBuf::from("project")),
+            ..Default::default()
+        })
+        .await
+        .expect("cwd update should succeed");
+
+    let state = session.state.lock().await;
+    assert_eq!(state.session_configuration.cwd, updated_cwd);
+    assert_eq!(
+        state.session_configuration.environments[0].cwd,
+        environment_cwd
+    );
+}
+
 #[tokio::test]
 async fn absolute_cwd_update_with_turn_environment_is_allowed() {
     let (session, _turn_context, _rx) = make_session_and_context_with_rx().await;