ref(slack): Compact Slack issue alert message layout

src/sentry/features/temporary.py

@@ -413,6 +413,8 @@ def register_temporary_features(manager: FeatureManager) -> None:
     manager.add("organizations:autofix-on-explorer", OrganizationFeature, FeatureHandlerStrategy.FLAGPOLE, api_expose=True)
     # Enable Seer Workflows in Slack
     manager.add("organizations:seer-slack-workflows", OrganizationFeature, FeatureHandlerStrategy.FLAGPOLE, api_expose=True)
+    # Enable new compact issue alert UI in Slack
+    manager.add("organizations:slack-compact-alerts", OrganizationFeature, FeatureHandlerStrategy.FLAGPOLE, api_expose=True)
     # Enable search query builder boolean operator select feature
     manager.add("organizations:search-query-builder-add-boolean-operator-select", OrganizationFeature, FeatureHandlerStrategy.FLAGPOLE, api_expose=True)
     # Enable search query builder conditionals in combobox menus

src/sentry/integrations/slack/message_builder/issues.py

@@ -85,6 +85,7 @@
 MAX_BLOCK_TEXT_LENGTH = 256
 USER_FEEDBACK_MAX_BLOCK_TEXT_LENGTH = 1500
 MAX_SUMMARY_HEADLINE_LENGTH = 50
+MAX_SUGGESTED_ASSIGNEES = 3
 
 
 def get_group_users_count(group: Group, rules: list[Rule] | None = None) -> int:
@@ -504,6 +505,9 @@ def __init__(
         self.skip_fallback = skip_fallback
         self.notes = notes
         self.issue_summary: dict[str, Any] | None = None
+        self._is_compact = features.has(
+            "organizations:slack-compact-alerts", self.group.organization
+        )
 
     def get_title_block(
         self,
@@ -514,6 +518,8 @@ def get_title_block(
         summary_headline = self.get_issue_summary_headline(event_or_group)
         title = summary_headline or build_attachment_title(event_or_group)
         title_emojis = self.get_title_emoji(has_action)
+        if self._is_compact:
+            title = build_attachment_title(event_or_group)
 
         title_text = f"{title_emojis} <{title_link}|*{escape_slack_text(title)}*>"
         return self.get_markdown_block(title_text)
@@ -537,6 +543,7 @@ def get_title_emoji(self, has_action: bool) -> str:
 
         return " ".join(title_emojis)
 
+    # Can be removed when 'slack-compact-alerts' is GA
     def get_issue_summary_headline(self, event_or_group: Event | GroupEvent | Group) -> str | None:
         if self.issue_summary is None:
             return None
@@ -570,13 +577,18 @@ def get_issue_summary_text(self) -> str | None:
 
         if not parts:
             return None
-        return escape_slack_markdown_text("\n\n".join(parts))
+
+        if self._is_compact:
+            return f"*Initial Guess*: {escape_slack_markdown_text('  '.join(parts))}"
+        else:
+            return escape_slack_markdown_text("\n\n".join(parts))
 
     def get_culprit_block(self, event_or_group: Event | GroupEvent | Group) -> SlackBlock | None:
         if event_or_group.culprit and isinstance(event_or_group.culprit, str):
             return self.get_context_block(event_or_group.culprit)
         return None
 
+    # 'small' param can be removed when 'slack-compact-alerts' is GA
     def get_text_block(self, text, small: bool = False) -> SlackBlock:
         if self.group.issue_category == GroupCategory.FEEDBACK:
             max_block_text_length = USER_FEEDBACK_MAX_BLOCK_TEXT_LENGTH
@@ -588,6 +600,7 @@ def get_text_block(self, text, small: bool = False) -> SlackBlock:
         else:
             return self.get_context_block(text)
 
+    # Can be removed when 'slack-compact-alerts' is GA
     def get_suggested_assignees_block(self, suggested_assignees: list[str]) -> SlackBlock:
         suggested_assignee_text = "Suggested Assignees: "
         for assignee in suggested_assignees:
@@ -638,6 +651,55 @@ def get_footer(self) -> SlackBlock:
         else:
             return self.get_context_block(text=footer, timestamp=timestamp)
 
+    def build_description_block(self, description_text: str) -> SlackBlock | None:
+        # Use issue summary if available (and not flagged for compact alerts), otherwise use the default text
+        summary_text: str | None = self.get_issue_summary_text()
+        if summary_text and not self._is_compact:
+            return self.get_text_block(summary_text, small=True)
+
+        text = description_text.lstrip(" ")
+        # XXX(CEO): sometimes text is " " and slack will error if we pass an empty string (now "")
+        return self.get_text_block(text) if text else None
+
+    def build_group_context_block(self, suggested_assignees: list[str]) -> SlackBlock | None:
+        """Combine stats (events, users, state, first seen) with suggested assignees in one context block."""
+        if not self._is_compact:
+            # add event count, user count, substate, first seen
+            context = get_context(self.group, self.rules)
+            if context:
+                return self.get_context_block(context)
+            return None
+
+        context_text = get_context(self.group, self.rules)
+
+        if suggested_assignees:
+            truncated_assignees = suggested_assignees[:MAX_SUGGESTED_ASSIGNEES]
+            suggested_text = ", ".join(truncated_assignees)
+            context_text += f"   Suggested: {suggested_text}"
+
+        context_text = context_text.strip()
+        if not context_text:
+            return None
+
+        return self.get_context_block(context_text)
+
+    def build_pre_footer_context_blocks(self, suggested_assignees: list[str]) -> list[SlackBlock]:
+        blocks = []
+        summary_text: str | None = self.get_issue_summary_text()
+        if self._is_compact and summary_text:
+            blocks.append(self.get_context_block(summary_text))
+
+        if not self._is_compact and len(suggested_assignees) > 0:
+            blocks.append(self.get_suggested_assignees_block(suggested_assignees))
+
+        if not self._is_compact:
+            # add suspect commit info
+            suspect_commit_text = get_suspect_commit_text(self.group)
+            if suspect_commit_text:
+                blocks.append(self.get_context_block(suspect_commit_text))
+
+        return blocks
+
     def build(self, notification_uuid: str | None = None) -> SlackBlock:
         self.issue_summary = fetch_issue_summary(self.group)
 
@@ -719,17 +781,8 @@ def build(self, notification_uuid: str | None = None) -> SlackBlock:
         if culprit_block := self.get_culprit_block(event_or_group):
             blocks.append(culprit_block)
 
-        # Use issue summary if available, otherwise use the default text
-        if summary_text := self.get_issue_summary_text():
-            blocks.append(self.get_text_block(summary_text, small=True))
-        else:
-            text = text.lstrip(" ")
-            # XXX(CEO): sometimes text is " " and slack will error if we pass an empty string (now "")
-            if text:
-                blocks.append(self.get_text_block(text))
-
-        if self.actions:
-            blocks.append(self.get_markdown_block(action_text))
+        if description_block := self.build_description_block(text):
+            blocks.append(description_block)
 
         # set up block id
         block_id = {"issue": self.group.id}
@@ -741,18 +794,28 @@ def build(self, notification_uuid: str | None = None) -> SlackBlock:
         if tags:
             blocks.append(self.get_tags_block(tags, block_id))
 
-        # add event count, user count, substate, first seen
-        context = get_context(self.group, self.rules)
-        if context:
-            blocks.append(self.get_context_block(context))
-
-        # build actions
-        actions = []
         try:
             assignee = self.group.get_assignee()
         except Actor.InvalidActor:
             assignee = None
 
+        suggested_assignees = []
+        if event_for_tags:
+            suggested_assignees = get_suggested_assignees(
+                self.group.project, event_for_tags, assignee
+            )
+
+        if group_context_block := self.build_group_context_block(
+            suggested_assignees=suggested_assignees
+        ):
+            blocks.append(group_context_block)
+
+        # If an action has been taken, add the text for it (e.g. "Issue resolved by <@U0234567890>")
+        if self.actions:
+            blocks.append(self.get_markdown_block(action_text))
+
+        # build actions
+        actions = []
         for action in payload_actions:
             if action.label in (
                 "Archive",
@@ -787,19 +850,8 @@ def build(self, notification_uuid: str | None = None) -> SlackBlock:
             action_block = {"type": "actions", "elements": [action for action in actions]}
             blocks.append(action_block)
 
-        # suggested assignees
-        suggested_assignees = []
-        if event_for_tags:
-            suggested_assignees = get_suggested_assignees(
-                self.group.project, event_for_tags, assignee
-            )
-        if len(suggested_assignees) > 0:
-            blocks.append(self.get_suggested_assignees_block(suggested_assignees))
-
-        # add suspect commit info
-        suspect_commit_text = get_suspect_commit_text(self.group)
-        if suspect_commit_text:
-            blocks.append(self.get_context_block(suspect_commit_text))
+        if pre_footer_context_block := self.build_pre_footer_context_blocks(suggested_assignees):
+            blocks.extend(pre_footer_context_block)
 
         # add notes
         if self.notes:
@@ -808,7 +860,8 @@ def build(self, notification_uuid: str | None = None) -> SlackBlock:
 
         # build footer block
         blocks.append(self.get_footer())
-        blocks.append(self.get_divider())
+        if not self._is_compact:
+            blocks.append(self.get_divider())
 
         chart_block = ImageBlockBuilder(group=self.group).build_image_block()
         if chart_block:

tests/sentry/integrations/slack/test_message_builder.py

@@ -1139,6 +1139,160 @@ def test_build_group_block_with_ai_summary_without_org_acknowledgement(
         blocks = SlackIssuesMessageBuilder(group).build()
         assert "IntegrationError" in blocks["blocks"][0]["text"]["text"]
 
+    @with_feature("organizations:slack-compact-alerts")
+    def test_compact_alerts_basic_layout(self) -> None:
+        """
+        Test that with the slack-compact-alerts flag enabled, the message uses a compact layout:
+        - No divider at the end
+        - Context block includes stats
+        """
+        event = self.store_event(
+            data={
+                "event_id": "a" * 32,
+                "message": "IntegrationError",
+                "fingerprint": ["group-1"],
+                "exception": {
+                    "values": [
+                        {
+                            "type": "IntegrationError",
+                            "value": "Identity not found.",
+                        }
+                    ]
+                },
+                "level": "error",
+            },
+            project_id=self.project.id,
+        )
+        assert event.group
+        group = event.group
+        group.type = ErrorGroupType.type_id
+        group.save()
+
+        self.project.flags.has_releases = True
+        self.project.save(update_fields=["flags"])
+
+        blocks = SlackIssuesMessageBuilder(group).build()
+
+        assert "IntegrationError" in blocks["blocks"][0]["text"]["text"]
+        assert blocks["blocks"][-1]["type"] != "divider"
+
+    @with_feature("organizations:slack-compact-alerts")
+    @override_options({"alerts.issue_summary_timeout": 5})
+    @with_feature({"organizations:gen-ai-features"})
+    @patch(
+        "sentry.integrations.utils.issue_summary_for_alerts.get_seer_org_acknowledgement",
+        return_value=True,
+    )
+    def test_compact_alerts_with_ai_summary(self, mock_get_seer_org_acknowledgement) -> None:
+        """
+        Test that with the slack-compact-alerts flag enabled and AI summary available:
+        - Title uses build_attachment_title() (not AI headline)
+        - Issue summary appears after action buttons as context with "Initial Guess:" prefix
+        """
+        event = self.store_event(
+            data={
+                "event_id": "a" * 32,
+                "message": "IntegrationError",
+                "fingerprint": ["group-1"],
+                "exception": {
+                    "values": [
+                        {
+                            "type": "IntegrationError",
+                            "value": "Identity not found.",
+                        }
+                    ]
+                },
+                "level": "error",
+            },
+            project_id=self.project.id,
+        )
+        assert event.group
+        group = event.group
+        group.type = ErrorGroupType.type_id
+        group.save()
+
+        self.project.flags.has_releases = True
+        self.project.save(update_fields=["flags"])
+        self.project.update_option("sentry:seer_scanner_automation", True)
+        self.organization.update_option("sentry:enable_seer_enhanced_alerts", True)
+
+        mock_summary = {
+            "headline": "Custom AI Title",
+            "whatsWrong": "This is what's wrong with the issue",
+            "trace": "This is trace information",
+            "possibleCause": "This is a possible cause",
+        }
+        patch_path = "sentry.integrations.utils.issue_summary_for_alerts.get_issue_summary"
+        serializer_path = "sentry.api.serializers.models.event.EventSerializer.serialize"
+        serializer_mock = Mock(return_value={})
+
+        with (
+            patch(patch_path) as mock_get_summary,
+            patch(serializer_path, serializer_mock),
+        ):
+            mock_get_summary.return_value = (mock_summary, 200)
+
+            blocks = SlackIssuesMessageBuilder(group).build()
+
+            title_block = blocks["blocks"][0]["text"]["text"]
+            assert "IntegrationError" in title_block
+            assert "Custom AI Title" not in title_block
+
+            found_initial_guess = False
+            for block in blocks["blocks"]:
+                if block.get("type") == "context":
+                    elements = block.get("elements", [])
+                    for element in elements:
+                        if "Initial Guess" in element.get("text", ""):
+                            found_initial_guess = True
+                            assert "This is a possible cause" in element["text"]
+                            break
+
+            assert found_initial_guess, "Initial Guess context block not found"
+            assert blocks["blocks"][-1]["type"] != "divider"
+
+    @with_feature("organizations:slack-compact-alerts")
+    def test_compact_alerts_context_includes_suggested_assignees(self) -> None:
+        """
+        Test that with compact alerts, suggested assignees are included in the context block
+        rather than in a separate block.
+        """
+        event = self.store_event(
+            data={
+                "event_id": "a" * 32,
+                "message": "Hello world",
+                "fingerprint": ["group-1"],
+                "level": "error",
+                "stacktrace": {"frames": [{"filename": "foo.py"}]},
+            },
+            project_id=self.project.id,
+        )
+        assert event.group
+        group = event.group
+
+        # Set up ownership to create suggested assignees
+        rule = Rule(Matcher("path", "*"), [Owner("team", self.team.slug)])
+        ProjectOwnership.objects.create(project_id=self.project.id, schema=dump_schema([rule]))
+
+        blocks = SlackIssuesMessageBuilder(group, event).build()
+
+        found_suggested_in_context = False
+        found_old_suggested_assignees = False
+        for block in blocks["blocks"]:
+            if block.get("type") == "context":
+                elements = block.get("elements", [])
+                for element in elements:
+                    text = element.get("text", "")
+                    if "Suggested:" in text:
+                        found_suggested_in_context = True
+                    if "Suggested Assignees:" in text:
+                        found_old_suggested_assignees = True
+
+        assert found_suggested_in_context, "Suggested assignees should be in context block"
+        assert (
+            not found_old_suggested_assignees
+        ), "Old 'Suggested Assignees:' format should not appear"
+
 
 class BuildGroupAttachmentReplaysTest(TestCase):
     @patch("sentry.models.group.Group.has_replays")