fix: report fatal errors in plain print mode

reigner/cli/chat.py

@@ -236,7 +236,7 @@ async def _run_print(session: Session, query: str, *, json_output: bool) -> int:
     """Drive one query in headless mode. Returns the process exit code."""
     final: FinalAnswerEvent | None = None
     saw_clarification = False
-    saw_error = False
+    error_text: str | None = None
     async for event in session.run_stream(query):
         if json_output:
             print(to_json(event), flush=True)
@@ -245,7 +245,7 @@ async def _run_print(session: Session, query: str, *, json_output: bool) -> int:
         elif isinstance(event, ClarificationEvent):
             saw_clarification = True
         elif isinstance(event, ErrorEvent) and not event.recoverable:
-            saw_error = True
+            error_text = event.error
 
     if not json_output and final is not None:
         print(final.text)
@@ -259,7 +259,9 @@ async def _run_print(session: Session, query: str, *, json_output: bool) -> int:
                 err=True,
             )
         return EXIT_USAGE
-    if saw_error:
+    if error_text is not None:
+        if not json_output:
+            typer.echo(f"error: {error_text}", err=True)
         return EXIT_RUNTIME
     return EXIT_RUNTIME
 

tests/cli/test_chat.py

@@ -38,6 +38,28 @@ def test_print_plain_outputs_final_answer_only(patch_build_session) -> None:
     assert result.stdout.strip() == "the answer is 42"
 
 
+def test_print_plain_reports_fatal_error(monkeypatch: pytest.MonkeyPatch) -> None:
+    from reigner.cli import chat as chat_module
+    from reigner.harness.events import ErrorEvent
+
+    class ErrorSession:
+        async def run_stream(self, query):
+            yield ErrorEvent(
+                seq=1,
+                session_id="test",
+                turn=1,
+                error="adapter: openai package not installed",
+                recoverable=False,
+            )
+
+    monkeypatch.setattr(chat_module, "_build_session", lambda _path: ErrorSession())
+    result = runner.invoke(app, ["chat", "--print", "anything"])
+
+    assert result.exit_code == 1
+    assert result.stdout == ""
+    assert result.stderr == "error: adapter: openai package not installed\n"
+
+
 def test_print_json_emits_nd_json_event_stream(patch_build_session) -> None:
     from tests.cli.conftest import _final