diff --git a/cli/utils/output.py b/cli/utils/output.py
index c8a7096..ce8f880 100644
--- a/cli/utils/output.py
+++ b/cli/utils/output.py
@@ -43,7 +43,13 @@ def _table(self, data: Any) -> None:
         columns = list(rows[0].keys())
         numeric_cols = _detect_numeric_columns(rows, columns)
 
-        table = Table(box=box.ROUNDED, caption=f"Showing {len(rows)} rows")
+        is_tty = sys.stdout.isatty()
+
+        if is_tty:
+            table = Table(box=box.ROUNDED, caption=f"Showing {len(rows)} rows")
+        else:
+            table = Table(box=None, show_edge=False, pad_edge=False)
+
         for col in columns:
             justify = "right" if col in numeric_cols else "left"
             table.add_column(col, justify=justify)
@@ -53,6 +59,9 @@ def _table(self, data: Any) -> None:
 
         self._console.print(table)
 
+        if not is_tty:
+            err_console.print(f"Showing {len(rows)} rows")
+
     def _csv(self, data: Any) -> None:
         rows = _extract_rows(data)
         if not rows:
diff --git a/tests/test_output.py b/tests/test_output.py
new file mode 100644
index 0000000..e64bcc4
--- /dev/null
+++ b/tests/test_output.py
@@ -0,0 +1,63 @@
+from __future__ import annotations
+
+import io
+from unittest.mock import patch
+
+from rich.console import Console
+
+from cli.types.enums import OutputFormat
+from cli.utils.output import OutputRenderer
+
+SAMPLE_DATA = [
+    {"name": "alice", "age": 30},
+    {"name": "bob", "age": 25},
+]
+
+
+def _render_table(data: list, *, is_tty: bool) -> tuple[str, str]:
+    """Render table data and return (stdout_text, stderr_text)."""
+    out_buf = io.StringIO()
+    err_buf = io.StringIO()
+
+    out_console = Console(file=out_buf, force_terminal=is_tty, width=120)
+    err_console = Console(file=err_buf, force_terminal=False, width=120)
+
+    renderer = OutputRenderer(console=out_console)
+
+    with (
+        patch("sys.stdout.isatty", return_value=is_tty),
+        patch("cli.utils.output.err_console", err_console),
+    ):
+        renderer.render(data, OutputFormat.TABLE)
+
+    return out_buf.getvalue(), err_buf.getvalue()
+
+
+def test_tty_table_includes_box_characters():
+    stdout_text, _ = _render_table(SAMPLE_DATA, is_tty=True)
+    assert "╭" in stdout_text or "─" in stdout_text, (
+        "TTY table output should contain box-drawing characters"
+    )
+
+
+def test_non_tty_table_excludes_box_characters():
+    stdout_text, _ = _render_table(SAMPLE_DATA, is_tty=False)
+    assert "╭" not in stdout_text, "Piped output should not contain box char"
+    assert "╰" not in stdout_text, "Piped output should not contain box char"
+    assert "│" not in stdout_text, "Piped output should not contain box char"
+
+
+def test_non_tty_caption_goes_to_stderr():
+    stdout_text, stderr_text = _render_table(SAMPLE_DATA, is_tty=False)
+    assert "Showing 2 rows" not in stdout_text, (
+        "Caption should not appear in stdout when piped"
+    )
+    assert "Showing 2 rows" in stderr_text, "Caption should appear in stderr when piped"
+
+
+def test_tty_caption_in_stdout():
+    stdout_text, stderr_text = _render_table(SAMPLE_DATA, is_tty=True)
+    assert "Showing 2 rows" in stdout_text, "Caption should appear in stdout for TTY"
+    assert "Showing 2 rows" not in stderr_text, (
+        "Caption should not appear in stderr for TTY"
+    )