diff --git a/agent/prompt_builder.py b/agent/prompt_builder.py
index 319be7255e2..3ec4a40b392 100644
--- a/agent/prompt_builder.py
+++ b/agent/prompt_builder.py
@@ -88,12 +88,15 @@ def _find_hermes_md(cwd: Path) -> Optional[Path]:
     stop_at = _find_git_root(cwd)
     current = cwd.resolve()
 
-    for directory in [current, *current.parents]:
+    # When there is no git root, only check cwd itself – walking parents
+    # could pick up a .hermes.md planted in /tmp, /home, etc.
+    search_dirs = [current, *current.parents] if stop_at else [current]
+
+    for directory in search_dirs:
         for name in _HERMES_MD_NAMES:
             candidate = directory / name
             if candidate.is_file():
                 return candidate
-        # Stop walking at the git root (or filesystem root).
         if stop_at and directory == stop_at:
             break
     return None