diff --git a/src/ucode/agents/pi.py b/src/ucode/agents/pi.py
index e7c1760..f65b75e 100644
--- a/src/ucode/agents/pi.py
+++ b/src/ucode/agents/pi.py
@@ -237,7 +237,7 @@ def _refresh_forever(state: dict, stop_event: threading.Event) -> None:
 def build_runtime_env(token: str) -> dict[str, str]:
     env = os.environ.copy()
     env["OAUTH_TOKEN"] = token
-    env["HOME"] = str(PI_UCODE_HOME)
+    env["PI_CODING_AGENT_DIR"] = str(PI_CONFIG_DIR)
     return env
 
 
diff --git a/tests/test_agent_pi.py b/tests/test_agent_pi.py
index 0afc5fb..e0dbe84 100644
--- a/tests/test_agent_pi.py
+++ b/tests/test_agent_pi.py
@@ -242,7 +242,7 @@ def test_sets_oauth_token(self):
 
     def test_sets_ucode_home(self):
         env = pi.build_runtime_env("tok")
-        assert env["HOME"] == str(pi.PI_UCODE_HOME)
+        assert env["PI_CODING_AGENT_DIR"] == str(pi.PI_CONFIG_DIR)
 
 
 class TestPiValidateCmd:
diff --git a/tests/test_e2e.py b/tests/test_e2e.py
index 30ce287..a5aea6d 100644
--- a/tests/test_e2e.py
+++ b/tests/test_e2e.py
@@ -910,7 +910,10 @@ def test_launch_pi_per_model(self, tmp_path, monkeypatch, e2e_state, e2e_workspa
         config_path = pi_dir / "models.json"
         backup_path = tmp_path / "pi-models.backup.json"
         monkeypatch.setattr(pi, "PI_UCODE_HOME", pi_home)
+        monkeypatch.setattr(pi, "PI_CONFIG_DIR", pi_dir)
         monkeypatch.setattr(pi, "PI_CONFIG_PATH", config_path)
+        monkeypatch.setattr(pi, "PI_SETTINGS_PATH", pi_dir / "settings.json")
+        monkeypatch.setattr(pi, "PI_SETTINGS_BACKUP_PATH", tmp_path / "pi-settings.backup.json")
         monkeypatch.setattr(pi, "PI_BACKUP_PATH", backup_path)
 
         failures = []
diff --git a/tests/test_e2e_user_agent.py b/tests/test_e2e_user_agent.py
index 884e663..e6cec21 100644
--- a/tests/test_e2e_user_agent.py
+++ b/tests/test_e2e_user_agent.py
@@ -325,7 +325,10 @@ def test_user_agent_arrives_at_gateway(self, tmp_path, monkeypatch, capture_serv
 
         monkeypatch.setattr(config_io_mod, "APP_DIR", tmp_path)
         monkeypatch.setattr(pi, "PI_UCODE_HOME", pi_home)
+        monkeypatch.setattr(pi, "PI_CONFIG_DIR", pi_dir)
         monkeypatch.setattr(pi, "PI_CONFIG_PATH", config_path)
+        monkeypatch.setattr(pi, "PI_SETTINGS_PATH", pi_dir / "settings.json")
+        monkeypatch.setattr(pi, "PI_SETTINGS_BACKUP_PATH", tmp_path / "pi-settings.backup.json")
         monkeypatch.setattr(pi, "PI_BACKUP_PATH", tmp_path / "pi.backup.json")
 
         state = {