diff --git a/codex-rs/app-server/src/message_processor.rs b/codex-rs/app-server/src/message_processor.rs
index d3eee87ccd..8b8fb317f4 100644
--- a/codex-rs/app-server/src/message_processor.rs
+++ b/codex-rs/app-server/src/message_processor.rs
@@ -95,6 +95,8 @@ use tokio::time::timeout;
 use tracing::Instrument;
 
 const EXTERNAL_AUTH_REFRESH_TIMEOUT: Duration = Duration::from_secs(10);
+const TEST_DISABLE_PLUGIN_STARTUP_TASKS_ENV_VAR: &str =
+    "CODEX_APP_SERVER_TEST_DISABLE_PLUGIN_STARTUP_TASKS";
 
 #[derive(Clone)]
 struct ExternalAuthRefreshBridge {
@@ -315,11 +317,13 @@ impl MessageProcessor {
             feedback,
             log_db,
         });
-        // Keep plugin startup warmups aligned at app-server startup.
-        // TODO(xl): Move into PluginManager once this no longer depends on config feature gating.
-        thread_manager
-            .plugins_manager()
-            .maybe_start_plugin_startup_tasks_for_config(&config, auth_manager.clone());
+        if std::env::var_os(TEST_DISABLE_PLUGIN_STARTUP_TASKS_ENV_VAR).is_none() {
+            // Keep plugin startup warmups aligned at app-server startup.
+            // TODO(xl): Move into PluginManager once this no longer depends on config feature gating.
+            thread_manager
+                .plugins_manager()
+                .maybe_start_plugin_startup_tasks_for_config(&config, auth_manager.clone());
+        }
         let config_api = ConfigApi::new(
             config_manager,
             thread_manager.clone(),
diff --git a/codex-rs/app-server/tests/common/lib.rs b/codex-rs/app-server/tests/common/lib.rs
index 6ac26d8a56..2010235d20 100644
--- a/codex-rs/app-server/tests/common/lib.rs
+++ b/codex-rs/app-server/tests/common/lib.rs
@@ -26,6 +26,7 @@ pub use core_test_support::test_tmp_path;
 pub use core_test_support::test_tmp_path_buf;
 pub use mcp_process::DEFAULT_CLIENT_NAME;
 pub use mcp_process::McpProcess;
+pub use mcp_process::TEST_DISABLE_PLUGIN_STARTUP_TASKS_ENV_VAR;
 pub use mock_model_server::create_mock_responses_server_repeating_assistant;
 pub use mock_model_server::create_mock_responses_server_sequence;
 pub use mock_model_server::create_mock_responses_server_sequence_unchecked;
diff --git a/codex-rs/app-server/tests/common/mcp_process.rs b/codex-rs/app-server/tests/common/mcp_process.rs
index befa248e80..9b7f5b5339 100644
--- a/codex-rs/app-server/tests/common/mcp_process.rs
+++ b/codex-rs/app-server/tests/common/mcp_process.rs
@@ -106,6 +106,8 @@ pub struct McpProcess {
 }
 
 pub const DEFAULT_CLIENT_NAME: &str = "codex-app-server-tests";
+pub const TEST_DISABLE_PLUGIN_STARTUP_TASKS_ENV_VAR: &str =
+    "CODEX_APP_SERVER_TEST_DISABLE_PLUGIN_STARTUP_TASKS";
 const DISABLE_MANAGED_CONFIG_ENV_VAR: &str = "CODEX_APP_SERVER_DISABLE_MANAGED_CONFIG";
 
 impl McpProcess {
@@ -147,7 +149,8 @@ impl McpProcess {
         cmd.stderr(Stdio::piped());
         cmd.current_dir(codex_home);
         cmd.env("CODEX_HOME", codex_home);
-        cmd.env("RUST_LOG", "info");
+        cmd.env("RUST_LOG", "warn");
+        cmd.env(TEST_DISABLE_PLUGIN_STARTUP_TASKS_ENV_VAR, "1");
         // Keep integration tests isolated from host managed configuration.
         cmd.env(
             "CODEX_APP_SERVER_MANAGED_CONFIG_PATH",
diff --git a/codex-rs/app-server/tests/suite/v2/plugin_list.rs b/codex-rs/app-server/tests/suite/v2/plugin_list.rs
index f885f2cb7a..a10ce3e5af 100644
--- a/codex-rs/app-server/tests/suite/v2/plugin_list.rs
+++ b/codex-rs/app-server/tests/suite/v2/plugin_list.rs
@@ -4,6 +4,7 @@ use anyhow::Result;
 use anyhow::bail;
 use app_test_support::ChatGptAuthFixture;
 use app_test_support::McpProcess;
+use app_test_support::TEST_DISABLE_PLUGIN_STARTUP_TASKS_ENV_VAR;
 use app_test_support::to_response;
 use app_test_support::write_chatgpt_auth;
 use codex_app_server_protocol::JSONRPCResponse;
@@ -1066,7 +1067,11 @@ async fn app_server_startup_remote_plugin_sync_runs_once() -> Result<()> {
         .join(STARTUP_REMOTE_PLUGIN_SYNC_MARKER_FILE);
 
     {
-        let mut mcp = McpProcess::new(codex_home.path()).await?;
+        let mut mcp = McpProcess::new_with_env(
+            codex_home.path(),
+            &[(TEST_DISABLE_PLUGIN_STARTUP_TASKS_ENV_VAR, None)],
+        )
+        .await?;
         timeout(DEFAULT_TIMEOUT, mcp.initialize()).await??;
 
         wait_for_path_exists(&marker_path).await?;
@@ -1102,7 +1107,11 @@ async fn app_server_startup_remote_plugin_sync_runs_once() -> Result<()> {
     assert!(config.contains(r#"[plugins."linear@openai-curated"]"#));
 
     {
-        let mut mcp = McpProcess::new(codex_home.path()).await?;
+        let mut mcp = McpProcess::new_with_env(
+            codex_home.path(),
+            &[(TEST_DISABLE_PLUGIN_STARTUP_TASKS_ENV_VAR, None)],
+        )
+        .await?;
         timeout(DEFAULT_TIMEOUT, mcp.initialize()).await??;
     }
 
@@ -1490,7 +1499,11 @@ async fn plugin_list_uses_warmed_featured_plugin_ids_cache_on_first_request() ->
         .mount(&server)
         .await;
 
-    let mut mcp = McpProcess::new(codex_home.path()).await?;
+    let mut mcp = McpProcess::new_with_env(
+        codex_home.path(),
+        &[(TEST_DISABLE_PLUGIN_STARTUP_TASKS_ENV_VAR, None)],
+    )
+    .await?;
     timeout(DEFAULT_TIMEOUT, mcp.initialize()).await??;
     wait_for_featured_plugin_request_count(&server, /*expected_count*/ 1).await?;