diff --git a/codex-rs/app-server-client/src/lib.rs b/codex-rs/app-server-client/src/lib.rs
index e9b514bf5f..6e10cef255 100644
--- a/codex-rs/app-server-client/src/lib.rs
+++ b/codex-rs/app-server-client/src/lib.rs
@@ -2092,14 +2092,17 @@ mod tests {
     #[tokio::test]
     async fn runtime_start_args_forward_environment_manager() {
         let config = Arc::new(build_test_config().await);
-        let environment_manager = Arc::new(EnvironmentManager::create_for_tests(
-            Some("ws://127.0.0.1:8765".to_string()),
-            ExecServerRuntimePaths::new(
-                std::env::current_exe().expect("current exe"),
-                /*codex_linux_sandbox_exe*/ None,
+        let environment_manager = Arc::new(
+            EnvironmentManager::create_for_tests(
+                Some("ws://127.0.0.1:8765".to_string()),
+                ExecServerRuntimePaths::new(
+                    std::env::current_exe().expect("current exe"),
+                    /*codex_linux_sandbox_exe*/ None,
+                )
+                .expect("runtime paths"),
             )
-            .expect("runtime paths"),
-        ));
+            .await,
+        );
 
         let runtime_args = InProcessClientStartArgs {
             arg0_paths: Arg0DispatchPaths::default(),
diff --git a/codex-rs/app-server/src/lib.rs b/codex-rs/app-server/src/lib.rs
index f27261728e..2efdfef52e 100644
--- a/codex-rs/app-server/src/lib.rs
+++ b/codex-rs/app-server/src/lib.rs
@@ -420,12 +420,15 @@ pub async fn run_main_with_transport_options(
     auth: AppServerWebsocketAuthSettings,
     runtime_options: AppServerRuntimeOptions,
 ) -> IoResult<()> {
-    let environment_manager = Arc::new(EnvironmentManager::new(EnvironmentManagerArgs::new(
-        ExecServerRuntimePaths::from_optional_paths(
-            arg0_paths.codex_self_exe.clone(),
-            arg0_paths.codex_linux_sandbox_exe.clone(),
-        )?,
-    )));
+    let environment_manager = Arc::new(
+        EnvironmentManager::new(EnvironmentManagerArgs::new(
+            ExecServerRuntimePaths::from_optional_paths(
+                arg0_paths.codex_self_exe.clone(),
+                arg0_paths.codex_linux_sandbox_exe.clone(),
+            )?,
+        ))
+        .await,
+    );
     let (transport_event_tx, mut transport_event_rx) =
         mpsc::channel::<TransportEvent>(CHANNEL_CAPACITY);
     let (outgoing_tx, mut outgoing_rx) = mpsc::channel::<OutgoingEnvelope>(CHANNEL_CAPACITY);
diff --git a/codex-rs/core/src/connectors.rs b/codex-rs/core/src/connectors.rs
index 3c7ef672be..0bd53a50ee 100644
--- a/codex-rs/core/src/connectors.rs
+++ b/codex-rs/core/src/connectors.rs
@@ -202,7 +202,7 @@ pub async fn list_accessible_connectors_from_mcp_tools_with_options_and_status(
         config.codex_linux_sandbox_exe.clone(),
     )?;
     let environment_manager =
-        EnvironmentManager::new(EnvironmentManagerArgs::new(local_runtime_paths));
+        EnvironmentManager::new(EnvironmentManagerArgs::new(local_runtime_paths)).await;
     list_accessible_connectors_from_mcp_tools_with_environment_manager(
         config,
         force_refetch,
diff --git a/codex-rs/core/src/environment_selection.rs b/codex-rs/core/src/environment_selection.rs
index f14361bdb5..b4bd9cbe89 100644
--- a/codex-rs/core/src/environment_selection.rs
+++ b/codex-rs/core/src/environment_selection.rs
@@ -106,7 +106,8 @@ mod tests {
         let manager = EnvironmentManager::create_for_tests(
             Some("ws://127.0.0.1:8765".to_string()),
             test_runtime_paths(),
-        );
+        )
+        .await;
 
         assert_eq!(
             default_thread_environment_selections(&manager, &cwd),
diff --git a/codex-rs/core/src/prompt_debug.rs b/codex-rs/core/src/prompt_debug.rs
index 145e372981..1b0c75230c 100644
--- a/codex-rs/core/src/prompt_debug.rs
+++ b/codex-rs/core/src/prompt_debug.rs
@@ -48,9 +48,7 @@ pub async fn build_prompt_input(
         &config,
         Arc::clone(&auth_manager),
         SessionSource::Exec,
-        Arc::new(EnvironmentManager::new(EnvironmentManagerArgs::new(
-            local_runtime_paths,
-        ))),
+        Arc::new(EnvironmentManager::new(EnvironmentManagerArgs::new(local_runtime_paths)).await),
         /*analytics_events_client*/ None,
         state_db,
         thread_store,
diff --git a/codex-rs/core/src/thread_manager_tests.rs b/codex-rs/core/src/thread_manager_tests.rs
index 7ad54565ff..0f6afa05a6 100644
--- a/codex-rs/core/src/thread_manager_tests.rs
+++ b/codex-rs/core/src/thread_manager_tests.rs
@@ -318,10 +318,13 @@ async fn start_thread_accepts_explicit_environment_when_default_environment_is_d
         /*codex_linux_sandbox_exe*/ None,
     )
     .expect("runtime paths");
-    let environment_manager = Arc::new(codex_exec_server::EnvironmentManager::create_for_tests(
-        Some("none".to_string()),
-        runtime_paths,
-    ));
+    let environment_manager = Arc::new(
+        codex_exec_server::EnvironmentManager::create_for_tests(
+            Some("none".to_string()),
+            runtime_paths,
+        )
+        .await,
+    );
     let manager = ThreadManager::with_models_provider_and_home_for_tests(
         CodexAuth::from_api_key("dummy"),
         config.model_provider.clone(),
diff --git a/codex-rs/core/tests/common/test_codex.rs b/codex-rs/core/tests/common/test_codex.rs
index 5399d05292..1728f5bc5c 100644
--- a/codex-rs/core/tests/common/test_codex.rs
+++ b/codex-rs/core/tests/common/test_codex.rs
@@ -391,11 +391,13 @@ impl TestCodexBuilder {
             std::env::current_exe()?,
             /*codex_linux_sandbox_exe*/ None,
         )?;
-        let environment_manager =
-            Arc::new(codex_exec_server::EnvironmentManager::create_for_tests(
+        let environment_manager = Arc::new(
+            codex_exec_server::EnvironmentManager::create_for_tests(
                 exec_server_url,
                 local_runtime_paths,
-            ));
+            )
+            .await,
+        );
         let file_system = test_env.environment().get_filesystem();
         let mut workspace_setups = vec![];
         swap(&mut self.workspace_setups, &mut workspace_setups);
diff --git a/codex-rs/exec/src/lib.rs b/codex-rs/exec/src/lib.rs
index a8fba18f4a..b035a19517 100644
--- a/codex-rs/exec/src/lib.rs
+++ b/codex-rs/exec/src/lib.rs
@@ -518,9 +518,9 @@ pub async fn run_main(cli: Cli, arg0_paths: Arg0DispatchPaths) -> anyhow::Result
         feedback: CodexFeedback::new(),
         log_db: None,
         state_db: state_db.clone(),
-        environment_manager: std::sync::Arc::new(EnvironmentManager::new(
-            EnvironmentManagerArgs::new(local_runtime_paths),
-        )),
+        environment_manager: std::sync::Arc::new(
+            EnvironmentManager::new(EnvironmentManagerArgs::new(local_runtime_paths)).await,
+        ),
         config_warnings,
         session_source: SessionSource::Exec,
         enable_codex_api_key_env: true,
diff --git a/codex-rs/mcp-server/src/lib.rs b/codex-rs/mcp-server/src/lib.rs
index 63ddd0c3e5..2fd94e586a 100644
--- a/codex-rs/mcp-server/src/lib.rs
+++ b/codex-rs/mcp-server/src/lib.rs
@@ -61,12 +61,15 @@ pub async fn run_main(
     arg0_paths: Arg0DispatchPaths,
     cli_config_overrides: CliConfigOverrides,
 ) -> IoResult<()> {
-    let environment_manager = Arc::new(EnvironmentManager::new(EnvironmentManagerArgs::new(
-        ExecServerRuntimePaths::from_optional_paths(
-            arg0_paths.codex_self_exe.clone(),
-            arg0_paths.codex_linux_sandbox_exe.clone(),
-        )?,
-    )));
+    let environment_manager = Arc::new(
+        EnvironmentManager::new(EnvironmentManagerArgs::new(
+            ExecServerRuntimePaths::from_optional_paths(
+                arg0_paths.codex_self_exe.clone(),
+                arg0_paths.codex_linux_sandbox_exe.clone(),
+            )?,
+        ))
+        .await,
+    );
     // Parse CLI overrides once and derive the base Config eagerly so later
     // components do not need to work with raw TOML values.
     let cli_kv_overrides = cli_config_overrides.parse_overrides().map_err(|e| {
diff --git a/codex-rs/tui/src/lib.rs b/codex-rs/tui/src/lib.rs
index 5bcc6ffa26..b2e92a19b4 100644
--- a/codex-rs/tui/src/lib.rs
+++ b/codex-rs/tui/src/lib.rs
@@ -761,12 +761,15 @@ pub async fn run_main(
         }
     };
 
-    let environment_manager = Arc::new(EnvironmentManager::new(EnvironmentManagerArgs::new(
-        ExecServerRuntimePaths::from_optional_paths(
-            arg0_paths.codex_self_exe.clone(),
-            arg0_paths.codex_linux_sandbox_exe.clone(),
-        )?,
-    )));
+    let environment_manager = Arc::new(
+        EnvironmentManager::new(EnvironmentManagerArgs::new(
+            ExecServerRuntimePaths::from_optional_paths(
+                arg0_paths.codex_self_exe.clone(),
+                arg0_paths.codex_linux_sandbox_exe.clone(),
+            )?,
+        ))
+        .await,
+    );
     let cwd = cli.cwd.clone();
     let config_cwd =
         config_cwd_for_app_server_target(cwd.as_deref(), &app_server_target, &environment_manager)?;
@@ -2138,7 +2141,8 @@ mod tests {
                 std::env::current_exe().expect("current exe"),
                 /*codex_linux_sandbox_exe*/ None,
             )?,
-        );
+        )
+        .await;
 
         let config_cwd =
             config_cwd_for_app_server_target(Some(remote_only_cwd), &target, &environment_manager)?;