diff --git a/pyproject.toml b/pyproject.toml
index d8ac023f..8b8bfd95 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -25,6 +25,7 @@ dependencies = [
 ]
 
 [project.optional-dependencies]
+dev = ["pytest", "pexpect"]
 acp = [
   "agent-client-protocol>=0.8,<1",
 ]
diff --git a/tests/test_tui_e2e.py b/tests/test_tui_e2e.py
index 443defcc..eaa82441 100644
--- a/tests/test_tui_e2e.py
+++ b/tests/test_tui_e2e.py
@@ -15,9 +15,14 @@
 from pathlib import Path
 from typing import Any, Callable
 
-import pexpect
 import pytest
 
+# Imported lazily: pexpect is only needed by these TUI end-to-end tests.
+# A module-level `import pexpect` runs before the skipif mark below, so on an
+# install without it pytest aborts collection of the whole suite instead of
+# skipping this one file.
+pexpect = pytest.importorskip("pexpect")
+
 
 ROOT = Path(__file__).resolve().parents[1]
 pytestmark = pytest.mark.skipif(shutil.which("script") is None, reason="`script` is required for TUI e2e tests")