Fix Cookbook serve exit code reporting

routes/cookbook_helpers.py

@@ -225,6 +225,15 @@ def _append_serve_preflight_exit_lines(runner_lines: list[str], *, keep_shell_op
     runner_lines.append('fi')
 
 
+def _append_serve_exit_code_lines(runner_lines: list[str], *, keep_shell_open: bool) -> None:
+    """Append serve-runner lines that preserve and report the command exit code."""
+    runner_lines.append('ODYSSEUS_CMD_EXIT=$?')
+    if keep_shell_open:
+        runner_lines.append('echo ""; echo "=== Process exited with code $ODYSSEUS_CMD_EXIT ==="; exec "${SHELL:-/bin/bash}"')
+    else:
+        runner_lines.append('echo ""; echo "=== Process exited with code $ODYSSEUS_CMD_EXIT ==="')
+
+
 class ModelDownloadRequest(BaseModel):
     repo_id: str
     include: str | None = None  # glob pattern e.g. "*Q4_K_M*"

routes/cookbook_routes.py

@@ -37,6 +37,7 @@ from routes.cookbook_helpers import (
     _validate_local_dir, _validate_ssh_port, _validate_gpus, _shell_path,
     _ps_squote, _bash_squote, _validate_serve_cmd, _parse_serve_phase,
     _safe_env_prefix, _local_tooling_path_export, _append_serve_preflight_exit_lines,
+    _append_serve_exit_code_lines,
     ModelDownloadRequest, ServeRequest,
 )
 
@@ -1086,10 +1087,10 @@ def setup_cookbook_routes() -> APIRouter:
             if local_windows:
                 # Detached background process — no interactive shell to keep open.
                 # Print the exit marker the status poller looks for, then stop.
-                runner_lines.append('echo ""; echo "=== Process exited with code $? ==="')
+                _append_serve_exit_code_lines(runner_lines, keep_shell_open=False)
             else:
                 # Keep shell open after exit so user can see errors
-                runner_lines.append('echo ""; echo "=== Process exited with code $? ==="; exec "${SHELL:-/bin/bash}"')
+                _append_serve_exit_code_lines(runner_lines, keep_shell_open=True)
 
             runner_path = TMUX_LOG_DIR / f"{session_id}_run.sh"
             runner_path.write_text("\n".join(runner_lines) + "\n", encoding="utf-8")

tests/test_cookbook_helpers.py

@@ -2,6 +2,7 @@ import pytest
 from fastapi import HTTPException
 
 from routes.cookbook_helpers import (
+    _append_serve_exit_code_lines,
     _append_serve_preflight_exit_lines,
     _local_tooling_path_export,
     _safe_env_prefix,
@@ -80,3 +81,14 @@ def test_serve_preflight_failure_keeps_tmux_pane_visible():
     assert 'echo "=== Process exited with code $ODYSSEUS_PREFLIGHT_EXIT ==="' in script
     assert 'exec "${SHELL:-/bin/bash}"' in script
     assert "exit 127" not in script
+
+
+def test_serve_runner_preserves_command_exit_code():
+    """The serve wrapper must capture `$?` before any echo resets it."""
+    runner_lines = ["vllm serve Qwen/Qwen3.6-35B-A3B-NVFP4 --host 0.0.0.0 --port 8000"]
+    _append_serve_exit_code_lines(runner_lines, keep_shell_open=True)
+    script = "\n".join(runner_lines)
+
+    assert "ODYSSEUS_CMD_EXIT=$?" in script
+    assert 'echo "=== Process exited with code $ODYSSEUS_CMD_EXIT ==="' in script
+    assert 'echo "=== Process exited with code $? ==="' not in script