diff --git a/strix/interface/tui/renderers/proxy_renderer.py b/strix/interface/tui/renderers/proxy_renderer.py
index 6fbbe121d..359b494d6 100644
--- a/strix/interface/tui/renderers/proxy_renderer.py
+++ b/strix/interface/tui/renderers/proxy_renderer.py
@@ -191,7 +191,7 @@ def render(cls, tool_data: dict[str, Any]) -> Static:  # noqa: PLR0912, PLR0915
                         if i < len(lines) - 1:
                             text.append("\n")
 
-                    if has_more or len(lines) > 15:
+                    if has_more or len(content.split("\n")) > 15:
                         text.append("\n")
                         text.append("  ... more content available", style="dim italic")
 
diff --git a/tests/test_proxy_renderer.py b/tests/test_proxy_renderer.py
new file mode 100644
index 000000000..341a1f40f
--- /dev/null
+++ b/tests/test_proxy_renderer.py
@@ -0,0 +1,46 @@
+"""Tests for the proxy tool TUI renderers."""
+
+from __future__ import annotations
+
+from rich.text import Text
+
+from strix.interface.tui.renderers.proxy_renderer import ViewRequestRenderer
+
+
+def _plain(static: object) -> str:
+    content = static.content  # type: ignore[attr-defined]
+    return content.plain if isinstance(content, Text) else str(content)
+
+
+def _render(content: str, *, has_more: bool) -> str:
+    tool_data = {
+        "status": "completed",
+        "result": {
+            "content": content,
+            "has_more": has_more,
+            "page": 1,
+            "total_lines": len(content.split("\n")),
+        },
+    }
+    return _plain(ViewRequestRenderer.render(tool_data))
+
+
+_MARKER = "... more content available"
+
+
+def test_more_content_hint_shown_when_over_fifteen_lines() -> None:
+    content = "\n".join(f"line{i}" for i in range(30))
+
+    assert _MARKER in _render(content, has_more=False)
+
+
+def test_no_more_content_hint_within_fifteen_lines() -> None:
+    content = "\n".join(f"line{i}" for i in range(5))
+
+    assert _MARKER not in _render(content, has_more=False)
+
+
+def test_more_content_hint_shown_when_has_more_flag_set() -> None:
+    content = "\n".join(f"line{i}" for i in range(3))
+
+    assert _MARKER in _render(content, has_more=True)