diff --git a/src/harbor_hypeman/environment.py b/src/harbor_hypeman/environment.py
index e03baa2..e24243e 100644
--- a/src/harbor_hypeman/environment.py
+++ b/src/harbor_hypeman/environment.py
@@ -315,7 +315,7 @@ async def exec(
         result = await exec_async(
             self._client,
             self._require_instance(),
-            ["/bin/sh", "-lc", command],
+            ["/bin/bash", "-lc", command],
             cwd=effective_exec_cwd(
                 cwd,
                 self.task_env_config.workdir,
diff --git a/tests/test_environment.py b/tests/test_environment.py
index a5e7d0b..1f018bc 100644
--- a/tests/test_environment.py
+++ b/tests/test_environment.py
@@ -164,7 +164,7 @@ async def test_start_creates_configured_workdir(
     assert args.args[:3] == (
         client,
         "instance-1",
-        ["/bin/sh", "-lc", "mkdir -p '/workspace with spaces'"],
+        ["/bin/bash", "-lc", "mkdir -p '/workspace with spaces'"],
     )
     assert args.kwargs["cwd"] == "/"
 
@@ -325,7 +325,7 @@ async def test_exec_uses_shell_workdir_environment_and_user(
     assert args.args[:3] == (
         client,
         "instance-1",
-        ["/bin/sh", "-lc", "su agent -s /bin/sh -c 'printf test'"],
+        ["/bin/bash", "-lc", "su agent -s /bin/sh -c 'printf test'"],
     )
     assert args.kwargs == {
         "cwd": "/workspace",