From e1877758d5de3b779bf345b4a3214ec7bb9cdad5 Mon Sep 17 00:00:00 2001
From: tony-chinchill <tony@chinchill.ai>
Date: Wed, 13 May 2026 17:52:42 -0700
Subject: [PATCH 1/2] fix(slack): skip @ inside email localparts when wrapping
 mentions

`SlackFormatConverter._convert_mentions_to_slack` and the AST text branch
in `_node_to_mrkdwn` rewrote `alice@example.com` to `alice<@example>.com`
because `(?<!<)@(\w+)` only skipped already-wrapped mentions, not the
localpart/domain boundary inside emails. The same one-character omission
existed in `SlackAdapter._resolve_outgoing_mentions`. Tightening the
lookbehind to `(?<![\w<])` skips both.

Real mentions still wrap:
- `Hey @alice` -> `Hey <@alice>`
- `@alice at start` -> `<@alice> at start`

Emails pass through:
- `Contact alice@example.com` -> `Contact alice@example.com`

Two regression tests in `tests/test_slack_format.py` cover the str path
and the AST path; existing mention tests untouched.
---
 src/chat_sdk/adapters/slack/adapter.py          |  2 +-
 src/chat_sdk/adapters/slack/format_converter.py |  4 ++--
 tests/test_slack_format.py                      | 17 +++++++++++++++++
 3 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/src/chat_sdk/adapters/slack/adapter.py b/src/chat_sdk/adapters/slack/adapter.py
index 1958c59..d7e4c36 100644
--- a/src/chat_sdk/adapters/slack/adapter.py
+++ b/src/chat_sdk/adapters/slack/adapter.py
@@ -1651,7 +1651,7 @@ async def _resolve_outgoing_mentions(self, text: str, thread_id: str) -> str:
             return text
         state = self._chat.get_state()
 
-        mention_pattern = re.compile(r"@(\w+)")
+        mention_pattern = re.compile(r"(?<!\w)@(\w+)")
         mentions: dict[str, list[str]] = {}
 
         for match in mention_pattern.finditer(text):
diff --git a/src/chat_sdk/adapters/slack/format_converter.py b/src/chat_sdk/adapters/slack/format_converter.py
index 323633e..4330e24 100644
--- a/src/chat_sdk/adapters/slack/format_converter.py
+++ b/src/chat_sdk/adapters/slack/format_converter.py
@@ -200,7 +200,7 @@ def flush_text() -> None:
 
     def _convert_mentions_to_slack(self, text: str) -> str:
         """Convert @mentions to Slack format: @name -> <@name>."""
-        return re.sub(r"(?<!<)@(\w+)", r"<@\1>", text)
+        return re.sub(r"(?<![\w<])@(\w+)", r"<@\1>", text)
 
     def _node_to_mrkdwn(self, node: Content) -> str:
         """Convert a single AST node to Slack mrkdwn."""
@@ -215,7 +215,7 @@ def _node_to_mrkdwn(self, node: Content) -> str:
 
         if node_type == "text":
             value = node.get("value", "")
-            return re.sub(r"(?<!<)@(\w+)", r"<@\1>", value)
+            return re.sub(r"(?<![\w<])@(\w+)", r"<@\1>", value)
 
         if node_type == "strong":
             content = "".join(self._node_to_mrkdwn(c) for c in children)
diff --git a/tests/test_slack_format.py b/tests/test_slack_format.py
index 6608062..39dc26e 100644
--- a/tests/test_slack_format.py
+++ b/tests/test_slack_format.py
@@ -199,6 +199,23 @@ def test_from_markdown_no_double_wrap(self):
         result = self.converter.from_markdown("Hey <@U12345>")
         assert result == "Hey <@U12345>"
 
+    def test_does_not_wrap_at_in_email_localpart(self):
+        """`@` preceded by a word char is part of an email address, not a mention.
+
+        Without the lookbehind tightening, `alice@example.com` was rewritten to
+        `alice<@example>.com`, surfacing a broken-looking mention in messages
+        that quote email addresses from upstream APIs.
+        """
+        result = self.converter.render_postable("Contact alice@example.com or bob@example.org")
+        assert "<@example>" not in result
+        assert "alice@example.com" in result
+        assert "bob@example.org" in result
+
+    def test_does_not_wrap_at_in_email_localpart_from_markdown_ast(self):
+        result = self.converter.render_postable({"markdown": "Contact alice@example.com"})
+        assert "<@example>" not in result
+        assert "alice@example.com" in result
+
 
 # ---------------------------------------------------------------------------
 # toPlainText

From f74d6214a44bfa34c294332b2d0cf24cc88136af Mon Sep 17 00:00:00 2001
From: patrick-chinchill <patrick@chinchill.ai>
Date: Fri, 15 May 2026 13:20:08 -0700
Subject: [PATCH 2/2] Update src/chat_sdk/adapters/slack/adapter.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
Signed-off-by: patrick-chinchill <patrick@chinchill.ai>
---
 src/chat_sdk/adapters/slack/adapter.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/chat_sdk/adapters/slack/adapter.py b/src/chat_sdk/adapters/slack/adapter.py
index d7e4c36..918240a 100644
--- a/src/chat_sdk/adapters/slack/adapter.py
+++ b/src/chat_sdk/adapters/slack/adapter.py
@@ -1651,7 +1651,7 @@ async def _resolve_outgoing_mentions(self, text: str, thread_id: str) -> str:
             return text
         state = self._chat.get_state()
 
-        mention_pattern = re.compile(r"(?<!\w)@(\w+)")
+        mention_pattern = re.compile(r"(?<![\w<])@(\w+)")
         mentions: dict[str, list[str]] = {}
 
         for match in mention_pattern.finditer(text):