Auto-detect Power Automate URLs and disable file attachments

- Change send_files from bool to Optional[bool] with None default
- Add _is_power_automate_url() helper to detect Power Automate webhooks
- Auto-disable files for Power Automate URLs (*.api.powerplatform.com)
- Keep files enabled for legacy webhooks (*.webhook.office.com)
- Explicit send_files: true/false always overrides auto-detection
- Update documentation with auto-detection behavior

Author: philslab-ninja

docs/configuration/sinks/ms-teams.rst

@@ -95,24 +95,33 @@ For example:
         webhook_url: teams-incoming-webhook
         prefer_redirect_to_platform: false
 
-Disabling File Attachments
+File Attachments
 -------------------------------------------------------------------
 
 MS Teams Power Automate workflow webhooks have a strict 28KB payload size limit.
-Alerts with embedded files (graphs, images, logs) may exceed this limit.
+Robusta automatically detects Power Automate URLs and disables file attachments
+to avoid exceeding this limit.
 
-To disable file attachments and reduce payload size, set ``send_files: false``:
+**Auto-detection behavior:**
+
+- Power Automate URLs (``*.api.powerplatform.com``): files disabled by default
+- Legacy webhook URLs (``*.webhook.office.com``): files enabled by default
+
+**Override auto-detection:**
+
+You can explicitly control file attachments using the ``send_files`` parameter:
 
 .. code-block:: yaml
 
      sinksConfig:
      - ms_teams_sink:
         name: main_ms_teams_sink
         webhook_url: teams-incoming-webhook
-        send_files: false  # Disables all file attachments to reduce payload size
+        send_files: true   # Force enable files (override auto-detection)
+        # send_files: false  # Force disable files
 
 .. note::
 
-    When ``send_files`` is false, all file attachments (images, logs, etc.)
-    will not be included in the MS Teams message. Text-based content will still
-    be sent normally.
+    When ``send_files`` is false (or auto-detected as false for Power Automate),
+    all file attachments (images, logs, graphs, etc.) will not be included in
+    the MS Teams message. Text-based content will still be sent normally.

src/robusta/core/sinks/msteams/msteams_sink_params.py

@@ -10,7 +10,7 @@
 class MsTeamsSinkParams(SinkBaseParams):
     webhook_url: str
     webhook_override: Optional[str] = None
-    send_files: bool = True  # Set False to disable file attachments (avoids 28KB limit)
+    send_files: Optional[bool] = None  # Auto-detect: False for Power Automate, True for legacy
 
     @classmethod
     def _get_sink_type(cls):

src/robusta/integrations/msteams/sender.py

@@ -1,4 +1,5 @@
 import logging
+from typing import Optional
 
 from robusta.core.reporting import (
     BaseBlock,
@@ -18,6 +19,15 @@
 from robusta.integrations.msteams.msteams_msg import MsTeamsMsg
 
 
+def _is_power_automate_url(url: str) -> bool:
+    """Check if URL is a Power Automate workflow webhook (has 28KB payload limit).
+
+    Power Automate URLs contain '.api.powerplatform.com' or '/powerautomate/'.
+    Legacy connector URLs use '*.webhook.office.com' and don't have the 28KB limit.
+    """
+    return ".api.powerplatform.com" in url or "/powerautomate/" in url
+
+
 class MsTeamsSender:
     @classmethod
     def __to_ms_teams(cls, block: BaseBlock, msg: MsTeamsMsg):
@@ -61,7 +71,7 @@ def send_finding_to_ms_teams(
         account_id: str,
         webhook_override: str,
         prefer_redirect_to_platform: bool,
-        send_files: bool = True,
+        send_files: Optional[bool] = None,
     ):
         """Send a finding to MS Teams via webhook.
 
@@ -73,12 +83,18 @@ def send_finding_to_ms_teams(
             account_id: The Robusta account ID.
             webhook_override: Optional webhook URL override pattern.
             prefer_redirect_to_platform: Whether to prefer platform links over Prometheus.
-            send_files: Whether to include file attachments. When False, all files
-                are filtered out to avoid exceeding MS Teams 28KB payload limit.
+            send_files: Whether to include file attachments. None (default) auto-detects
+                based on webhook URL: disabled for Power Automate (28KB limit), enabled
+                for legacy webhooks. Explicit True/False overrides auto-detection.
         """
         webhook_url = MsTeamsWebhookUrlTransformer.template(
             webhook_override=webhook_override, default_webhook_url=webhook_url, annotations=finding.subject.annotations
         )
+
+        # Auto-detect send_files based on webhook URL if not explicitly set
+        if send_files is None:
+            send_files = not _is_power_automate_url(webhook_url)
+
         msg = MsTeamsMsg(webhook_url, prefer_redirect_to_platform)
         msg.write_title_and_desc(platform_enabled, finding, cluster_name, account_id)