1 files changed, 28 insertions, 1 deletions

diff --git a/llamachat/ui.py b/llamachat/ui.py
index fd2380c..f599bdd 100644
--- a/llamachat/ui.py
+++ b/llamachat/ui.py
@@ -1291,6 +1291,33 @@ _PRE_STYLE = (
 )
 
 
+_FENCE_RE = re.compile(r"^\s{0,3}(`{3,}|~{3,})", re.MULTILINE)
+
+
+def _close_fences(text: str) -> str:
+    """Close an unterminated code fence and neuter a lone inline backtick.
+
+    A reply is streamed, so a fence is unclosed on nearly every frame; a
+    model can also emit an odd backtick by accident. Either way the rest of
+    the reply would reflow as code, which is how a whole message turns into
+    one grey block. Closing the fence here bounds the damage to the text
+    that was really meant as code.
+    """
+    fences = _FENCE_RE.findall(text)
+    if len(fences) % 2:
+        # Match the opener's own length; a longer run is legal and only a
+        # fence at least as long as the opener actually closes it.
+        closer = fences[-1][0] * max(3, len(fences[-1]))
+        nl = "" if text.endswith("\n") else "\n"
+        return f"{text}{nl}{closer}"
+    if not fences and text.count("`") % 2:
+        # No fences at all, one dangling inline tick: drop it rather than
+        # let it open a run to the end of the message.
+        head, _, tail = text.rpartition("`")
+        return head + tail
+    return text
+
+
 def _markdown_to_fragment(text: str) -> str:
     """Render markdown to an HTML fragment safe to splice into the page.
 
@@ -1300,7 +1327,7 @@ def _markdown_to_fragment(text: str) -> str:
     if not text:
         return ""
     doc = QTextDocument()
-    doc.setMarkdown(text, MARKDOWN_FLAGS)
+    doc.setMarkdown(_close_fences(text), MARKDOWN_FLAGS)
     html_text = doc.toHtml()
 
     start = html_text.find("<body")