diff --git a/codeflash/languages/javascript/test_runner.py b/codeflash/languages/javascript/test_runner.py
index a7ba0a974..32f9977d8 100644
--- a/codeflash/languages/javascript/test_runner.py
+++ b/codeflash/languages/javascript/test_runner.py
@@ -295,7 +295,11 @@ def _create_codeflash_jest_config(
         logger.debug("ts-jest not found in project dependencies, skipping transform config")
 
     # Create a wrapper Jest config
-    if original_jest_config:
+    # TypeScript configs (.ts) cannot be required from CommonJS modules
+    # because Node.js cannot parse TypeScript syntax in require().
+    # When the original config is TypeScript, we create a standalone config
+    # instead of trying to extend it via require().
+    if original_jest_config and original_jest_config.suffix != ".ts":
         # Since codeflash config is in the same directory as original, use simple relative path
         config_require_path = f"./{original_jest_config.name}"
 
@@ -305,6 +309,10 @@ def _create_codeflash_jest_config(
 
 module.exports = {{
   ...originalConfig,
+  // Disable globalSetup and globalTeardown to avoid external dependencies (e.g., Docker)
+  // Codeflash-generated tests should be self-contained and not require global setup/teardown
+  globalSetup: undefined,
+  globalTeardown: undefined,
   // Transform ESM packages that don't work with Jest's default config
   // Pattern handles both npm/yarn (node_modules/pkg) and pnpm (node_modules/.pnpm/pkg@version/node_modules/pkg)
   transformIgnorePatterns: [
@@ -320,6 +328,9 @@ def _create_codeflash_jest_config(
   testEnvironment: 'node',
   testRegex: '\\\\.(test|spec)\\\\.(js|ts|tsx)$',
   testPathIgnorePatterns: ['/dist/'],
+  // Disable globalSetup and globalTeardown to avoid external dependencies
+  globalSetup: undefined,
+  globalTeardown: undefined,
   // Transform ESM packages that don't work with Jest's default config
   // Pattern handles both npm/yarn and pnpm directory structures
   transformIgnorePatterns: [
@@ -382,12 +393,19 @@ def _create_runtime_jest_config(base_config_path: Path | None, project_root: Pat
     else:
         module_dirs_line_no_base = ""
 
-    if base_config_path:
+    # TypeScript configs (.ts) cannot be required from CommonJS modules
+    # because Node.js cannot parse TypeScript syntax in require().
+    # When the base config is TypeScript, we create a standalone config
+    # instead of trying to extend it via require().
+    if base_config_path and base_config_path.suffix != ".ts":
         require_path = f"./{base_config_path.name}"
         config_content = f"""// Auto-generated by codeflash - runtime config with test roots
 const baseConfig = require('{require_path}');
 module.exports = {{
   ...baseConfig,
+  // Disable globalSetup and globalTeardown to avoid external dependencies (e.g., Docker)
+  globalSetup: undefined,
+  globalTeardown: undefined,
   roots: [
     ...(baseConfig.roots || [__dirname]),
     {test_dirs_js},
@@ -399,6 +417,9 @@ def _create_runtime_jest_config(base_config_path: Path | None, project_root: Pat
     else:
         config_content = f"""// Auto-generated by codeflash - runtime config with test roots
 module.exports = {{
+  // Disable globalSetup and globalTeardown to avoid external dependencies
+  globalSetup: undefined,
+  globalTeardown: undefined,
   roots: ['{project_root}', {test_dirs_js}],
   testMatch: ['**/*.test.ts', '**/*.test.js', '**/*.test.tsx', '**/*.test.jsx'],
 {module_dirs_line_no_base}}};
@@ -421,9 +442,9 @@ def _create_runtime_jest_config(base_config_path: Path | None, project_root: Pat
 def _get_jest_config_for_project(project_root: Path) -> Path | None:
     """Get the appropriate Jest config for the project.
 
-    If the project uses bundler moduleResolution, creates and returns a
-    codeflash-compatible Jest config. Otherwise, returns the project's
-    existing Jest config.
+    Always creates a codeflash-compatible Jest config that disables globalSetup/globalTeardown
+    and handles ESM packages. If the project uses bundler moduleResolution, also creates a
+    compatible tsconfig.
 
     Args:
         project_root: Root of the project.
@@ -440,11 +461,15 @@ def _get_jest_config_for_project(project_root: Path) -> Path | None:
         logger.info("Detected bundler moduleResolution - creating compatible config")
         # Create codeflash-compatible tsconfig
         _create_codeflash_tsconfig(project_root)
-        # Create codeflash Jest config that uses it
-        codeflash_jest_config = _create_codeflash_jest_config(project_root, original_jest_config)
-        if codeflash_jest_config:
-            return codeflash_jest_config
 
+    # Always create codeflash Jest config to disable globalSetup/globalTeardown
+    # and handle ESM packages properly
+    codeflash_jest_config = _create_codeflash_jest_config(project_root, original_jest_config)
+    if codeflash_jest_config:
+        logger.debug(f"Using codeflash Jest config: {codeflash_jest_config}")
+        return codeflash_jest_config
+
+    # Fallback to original if codeflash config creation failed
     return original_jest_config
 
 
@@ -769,8 +794,21 @@ def run_jest_behavioral_tests(
 
     # Get test files to run
     test_files = [str(file.instrumented_behavior_file_path) for file in test_paths.test_files]
-    # Use provided project_root, or detect it as fallback
-    if project_root is None and test_files:
+    # In monorepos with --all mode, test_cfg.js_project_root may point to the wrong package
+    # (e.g., optimizing worker functions but project_root is set to server package).
+    # Detect the correct package from test file location to ensure Jest uses the right config.
+    if test_files and project_root:
+        first_test_file = Path(test_files[0])
+        detected_root = find_node_project_root(first_test_file)
+        # Only override if: (1) detected a different package root, (2) it has package.json,
+        # (3) both are peer packages (same parent directory)
+        if (detected_root and detected_root != project_root and
+            (detected_root / "package.json").exists() and
+            detected_root.parent == project_root.parent):
+            logger.debug(f"Monorepo: overriding project_root {project_root} with detected {detected_root}")
+            project_root = detected_root
+    elif project_root is None and test_files:
+        # Fallback: if no project_root provided, detect from test file
         first_test_file = Path(test_files[0])
         project_root = find_node_project_root(first_test_file)
 
@@ -1024,8 +1062,15 @@ def run_jest_benchmarking_tests(
 
     # Get performance test files
     test_files = [str(file.benchmarking_file_path) for file in test_paths.test_files if file.benchmarking_file_path]
-    # Use provided project_root, or detect it as fallback
-    if project_root is None and test_files:
+    # In monorepos, detect correct package from test file location
+    if test_files and project_root:
+        first_test_file = Path(test_files[0])
+        detected_root = find_node_project_root(first_test_file)
+        if (detected_root and detected_root != project_root and
+            (detected_root / "package.json").exists() and
+            detected_root.parent == project_root.parent):
+            project_root = detected_root
+    elif project_root is None and test_files:
         first_test_file = Path(test_files[0])
         project_root = find_node_project_root(first_test_file)
 
@@ -1198,8 +1243,15 @@ def run_jest_line_profile_tests(
         elif file.benchmarking_file_path:
             test_files.append(str(file.benchmarking_file_path))
 
-    # Use provided project_root, or detect it as fallback
-    if project_root is None and test_files:
+    # In monorepos, detect correct package from test file location
+    if test_files and project_root:
+        first_test_file = Path(test_files[0])
+        detected_root = find_node_project_root(first_test_file)
+        if (detected_root and detected_root != project_root and
+            (detected_root / "package.json").exists() and
+            detected_root.parent == project_root.parent):
+            project_root = detected_root
+    elif project_root is None and test_files:
         first_test_file = Path(test_files[0])
         project_root = find_node_project_root(first_test_file)
 
diff --git a/tests/languages/javascript/test_globalsetup_handling.py b/tests/languages/javascript/test_globalsetup_handling.py
new file mode 100644
index 000000000..6453c6359
--- /dev/null
+++ b/tests/languages/javascript/test_globalsetup_handling.py
@@ -0,0 +1,171 @@
+from pathlib import Path
+
+from codeflash.languages.javascript.test_runner import (
+    _create_codeflash_jest_config,
+    _create_runtime_jest_config,
+)
+
+
+def test_disables_globalsetup_and_globalteardown(tmp_path: Path) -> None:
+    project_root = tmp_path.resolve()
+
+    original_config = project_root / "jest.config.js"
+    original_config.write_text(
+        """
+module.exports = {
+  testEnvironment: 'node',
+  globalSetup: './globalSetup.ts',
+  globalTeardown: './globalTeardown.ts',
+  setupFilesAfterEnv: ['./setupTests.js'],
+};
+""",
+        encoding="utf-8",
+    )
+
+    codeflash_config = _create_codeflash_jest_config(
+        project_root=project_root,
+        original_jest_config=original_config,
+        for_esm=False,
+    )
+
+    assert codeflash_config is not None
+    assert codeflash_config.exists()
+
+    config_content = codeflash_config.read_text(encoding="utf-8")
+
+    assert "globalSetup: undefined" in config_content
+    assert "globalTeardown: undefined" in config_content
+
+    # The original scripts are not embedded in the wrapper config (spread at runtime)
+    assert "./globalSetup.ts" not in config_content
+    assert "./globalTeardown.ts" not in config_content
+
+
+def test_disables_globalsetup_in_minimal_config(tmp_path: Path) -> None:
+    project_root = tmp_path.resolve()
+
+    codeflash_config = _create_codeflash_jest_config(
+        project_root=project_root,
+        original_jest_config=None,
+        for_esm=False,
+    )
+
+    assert codeflash_config is not None
+    assert codeflash_config.exists()
+
+    config_content = codeflash_config.read_text(encoding="utf-8")
+
+    assert "globalSetup: undefined" in config_content
+    assert "globalTeardown: undefined" in config_content
+
+
+def test_preserves_setupfilesafterenv(tmp_path: Path) -> None:
+    project_root = tmp_path.resolve()
+
+    original_config = project_root / "jest.config.js"
+    original_config.write_text(
+        """
+module.exports = {
+  testEnvironment: 'node',
+  globalSetup: './globalSetup.ts',
+  setupFilesAfterEnv: ['./setupTests.js'],
+};
+""",
+        encoding="utf-8",
+    )
+
+    codeflash_config = _create_codeflash_jest_config(
+        project_root=project_root,
+        original_jest_config=original_config,
+        for_esm=False,
+    )
+
+    assert codeflash_config is not None
+
+    config_content = codeflash_config.read_text(encoding="utf-8")
+
+    assert "globalSetup: undefined" in config_content
+    assert "setupFilesAfterEnv: undefined" not in config_content
+
+
+def test_runtime_config_disables_globalsetup_with_base_config(tmp_path: Path) -> None:
+    project_root = tmp_path.resolve()
+
+    base_config = project_root / "jest.config.js"
+    base_config.write_text(
+        """
+module.exports = {
+  testEnvironment: 'node',
+  globalSetup: './globalSetup.ts',
+};
+""",
+        encoding="utf-8",
+    )
+
+    test_dirs = {str(project_root / "tests")}
+    runtime_config = _create_runtime_jest_config(
+        base_config_path=base_config,
+        project_root=project_root,
+        test_dirs=test_dirs,
+    )
+
+    assert runtime_config is not None
+    assert runtime_config.exists()
+
+    config_content = runtime_config.read_text(encoding="utf-8")
+
+    assert "globalSetup: undefined" in config_content
+    assert "globalTeardown: undefined" in config_content
+
+
+def test_runtime_config_disables_globalsetup_standalone(tmp_path: Path) -> None:
+    project_root = tmp_path.resolve()
+
+    test_dirs = {str(project_root / "tests")}
+    runtime_config = _create_runtime_jest_config(
+        base_config_path=None,
+        project_root=project_root,
+        test_dirs=test_dirs,
+    )
+
+    assert runtime_config is not None
+    assert runtime_config.exists()
+
+    config_content = runtime_config.read_text(encoding="utf-8")
+
+    assert "globalSetup: undefined" in config_content
+    assert "globalTeardown: undefined" in config_content
+
+
+def test_runtime_config_disables_globalsetup_with_typescript_base(tmp_path: Path) -> None:
+    project_root = tmp_path.resolve()
+
+    base_config = project_root / "jest.config.ts"
+    base_config.write_text(
+        """
+import { Config } from "jest";
+export default {
+  testEnvironment: 'node',
+  globalSetup: './globalSetup.ts',
+} as Config;
+""",
+        encoding="utf-8",
+    )
+
+    test_dirs = {str(project_root / "tests")}
+    runtime_config = _create_runtime_jest_config(
+        base_config_path=base_config,
+        project_root=project_root,
+        test_dirs=test_dirs,
+    )
+
+    assert runtime_config is not None
+    assert runtime_config.exists()
+
+    config_content = runtime_config.read_text(encoding="utf-8")
+
+    assert "globalSetup: undefined" in config_content
+    assert "globalTeardown: undefined" in config_content
+
+    # Should NOT try to require the TypeScript config
+    assert "require" not in config_content