From 78c7e22839f101e731d82b35276c3653c1aabcc8 Mon Sep 17 00:00:00 2001
From: Hermine <hermes@tobaiaes.dev>
Date: Tue, 9 Jun 2026 00:38:55 +0200
Subject: [PATCH] fix(telegram): always apply MarkdownV2 formatting on
 edit_message

Previously, edit_message(finalize=False) sent content as plain text
without parse_mode=MarkdownV2, while edit_message(finalize=True) and
send() both applied MarkdownV2 formatting. This caused tool progress
edits to replace a correctly formatted message with raw markdown text,
breaking code blocks, headers, bold, and other formatting in the
Telegram chat.

The fix always applies format_message() + parse_mode=MARKDOWN_V2
regardless of the finalize flag, with the same fallback to plain text
on parse errors. Added logging for the fallback case (previously
silent).

Fixes: #25710 (related)
---
 gateway/platforms/telegram.py | 31 +++++++++++++++++++------------
 gateway/run.py                |  5 ++++-
 2 files changed, 23 insertions(+), 13 deletions(-)

diff --git a/gateway/platforms/telegram.py b/gateway/platforms/telegram.py
index b97d430d4a44..549450d5246f 100644
--- a/gateway/platforms/telegram.py
+++ b/gateway/platforms/telegram.py
@@ -2188,14 +2188,11 @@ async def edit_message(
             )
 
         try:
-            if not finalize:
-                await self._bot.edit_message_text(
-                    chat_id=int(chat_id),
-                    message_id=int(message_id),
-                    text=content,
-                )
-                return SendResult(success=True, message_id=message_id)
-
+            # Always apply MarkdownV2 formatting on edit, even for
+            # intermediate (finalize=False) updates.  Without this, a
+            # progress edit that follows an initial formatted send()
+            # replaces the MarkdownV2-rendered message with raw plain
+            # text — breaking code blocks, bold, headers, etc.
             formatted = self.format_message(content)
             try:
                 await self._bot.edit_message_text(
@@ -2209,6 +2206,10 @@ async def edit_message(
                 if "not modified" in str(fmt_err).lower():
                     return SendResult(success=True, message_id=message_id)
                 # Fallback: retry without markdown formatting
+                logger.warning(
+                    "[%s] MarkdownV2 edit failed, falling back to plain text: %s",
+                    self.name, fmt_err,
+                )
                 await self._bot.edit_message_text(
                     chat_id=int(chat_id),
                     message_id=int(message_id),
@@ -4369,7 +4370,8 @@ def _ph(value: str) -> str:
         text = _wrap_markdown_tables(text)
 
         # 1) Protect fenced code blocks (``` ... ```)
-        #    Per MarkdownV2 spec, \ and ` inside pre/code must be escaped.
+        #    Per MarkdownV2 spec, these characters must be escaped inside
+        #    pre/code blocks too: \ ` * _ { } [ ] ( ) # + - . ! >
         def _protect_fenced(m):
             raw = m.group(0)
             # Split off opening ``` (with optional language) and closing ```
@@ -4377,7 +4379,7 @@ def _protect_fenced(m):
             opening = raw[:open_end]
             body_and_close = raw[open_end:]
             body = body_and_close[:-3]
-            body = body.replace('\\', '\\\\').replace('`', '\\`')
+            body = _escape_mdv2(body)
             return _ph(opening + body + '```')
 
         text = re.sub(
@@ -4387,10 +4389,15 @@ def _protect_fenced(m):
         )
 
         # 2) Protect inline code (`...`)
-        #    Escape \ inside inline code per MarkdownV2 spec.
+        #    Per MarkdownV2 spec, all special chars must be escaped inside code.
+        def _protect_inline(m):
+            inner = m.group(0)[1:-1]  # strip outer backticks
+            escaped = _escape_mdv2(inner)
+            return _ph(f'`{escaped}`')
+
         text = re.sub(
             r'(`[^`]+`)',
-            lambda m: _ph(m.group(0).replace('\\', '\\\\')),
+            _protect_inline,
             text,
         )
 
diff --git a/gateway/run.py b/gateway/run.py
index d5b39c31df11..1b018207f1de 100644
--- a/gateway/run.py
+++ b/gateway/run.py
@@ -12990,7 +12990,10 @@ def progress_callback(event_type: str, tool_name: str = None, preview: str = Non
                 and isinstance(args.get("command"), str)
                 and args["command"].strip()
             ):
-                _bash_block = f"```bash\n{args['command'].rstrip()}\n```"
+                # Escape triple-backticks inside the command so they don't
+                # break the fenced code-block boundary that wraps them.
+                _cmd = args['command'].rstrip().replace('```', '\\`\\`\\`')
+                _bash_block = f"```bash\n{_cmd}\n```"
             
             # Verbose mode: show detailed arguments, respects tool_preview_length
             if progress_mode == "verbose":