feat: add Telegram file attachment support (inbound + outbound)

Inbound:
- tg-ingest detects document/photo/audio/video/voice attachments
- Downloads files via Telegram Bot API (getFile + download)
- Inlines small text files (<50KB) directly in the prompt
- Stores binary/large files to S3 (attachments/{chat_id}/{update_id}/{filename})
- agent-runner appends file context to the AgentCore prompt

Outbound:
- New send_file tool for the agent to send documents back to users
- TelegramAdapter.send_document uses multipart/form-data POST
- CDK grants tg-ingest S3 write access and passes bucket name env var

agentclaw/app/agent_claw_main/channels/telegram.py

@@ -63,6 +63,43 @@ class TelegramAdapter:
             import traceback
             print(f'[telegram] send_typing failed: {e}\n{traceback.format_exc()}')
 
+    def send_document(self, file_bytes: bytes, filename: str, caption: str = '') -> str:
+        """Send a file as a Telegram document using multipart/form-data. Returns message_id."""
+        import io
+        token = self._get_token()
+        url = f'https://api.telegram.org/bot{token}/sendDocument'
+
+        boundary = '----AgentClawBoundary'
+        body = io.BytesIO()
+
+        def add_field(name: str, value: str):
+            body.write(f'--{boundary}\r\n'.encode())
+            body.write(f'Content-Disposition: form-data; name="{name}"\r\n\r\n'.encode())
+            body.write(f'{value}\r\n'.encode())
+
+        def add_file(name: str, fname: str, data: bytes):
+            body.write(f'--{boundary}\r\n'.encode())
+            body.write(f'Content-Disposition: form-data; name="{name}"; filename="{fname}"\r\n'.encode())
+            body.write(b'Content-Type: application/octet-stream\r\n\r\n')
+            body.write(data)
+            body.write(b'\r\n')
+
+        add_field('chat_id', self.chat_id)
+        if self.thread_id is not None:
+            add_field('message_thread_id', str(self.thread_id))
+        if caption:
+            add_field('caption', caption)
+        add_file('document', filename, file_bytes)
+        body.write(f'--{boundary}--\r\n'.encode())
+
+        req = urllib.request.Request(
+            url, data=body.getvalue(),
+            headers={'Content-Type': f'multipart/form-data; boundary={boundary}'},
+        )
+        with urllib.request.urlopen(req, timeout=60) as resp:
+            result = json.loads(resp.read())
+        return str(result.get('result', {}).get('message_id', ''))
+
     def edit(self, message_id: str, text: str) -> None:
         """Edit an existing message in-place."""
         try:

agentclaw/app/agent_claw_main/main.py

@@ -17,6 +17,7 @@ from tools.scheduler import schedule_reminder, list_reminders, cancel_reminder
 import tools.scheduler as _scheduler_module
 from tools.home_assistant import home_assistant, set_ha_config
 from tools.google_workspace import list_calendars, get_calendar_events, list_gmail_messages, get_gmail_message
+from tools.send_file import send_file as _send_file_impl
 import tools.google_workspace as _gws
 import httpx
 import botocore.auth
@@ -74,6 +75,19 @@ def web_search(query: str) -> str:
     return web_tools.brave_search(query)
 
 
+@tool
+def send_file(file_content: str, filename: str, caption: str = '') -> str:
+    """Send a file to the user as a Telegram document attachment.
+    Use this when you need to send code, data, or any text content as a downloadable file.
+
+    Args:
+        file_content: The text content of the file to send.
+        filename: The filename with extension (e.g. 'report.txt', 'data.csv', 'script.py').
+        caption: Optional caption to display with the file.
+    """
+    return _send_file_impl(file_content, filename, caption)
+
+
 @tool
 def web_fetch(url: str) -> str:
     """Fetch and extract readable text content from a URL."""
@@ -360,7 +374,7 @@ async def main(payload: dict, context):
                   home_assistant, connect_google_account, list_google_accounts, remove_google_account,
                   manage_service, schedule_reminder, list_reminders, cancel_reminder,
                   list_calendars, get_calendar_events, list_gmail_messages, get_gmail_message,
-                  run_code]
+                  run_code, send_file]
 
     agent = Agent(
         model=model,

agentclaw/app/agent_claw_main/tools/send_file.py

@@ -0,0 +1,20 @@
+"""Send file tool — sends documents to the user via Telegram."""
+from tools import messaging
+
+
+def send_file(file_content: str, filename: str, caption: str = '') -> str:
+    """Send a file to the user as a Telegram document attachment.
+
+    Args:
+        file_content: The text content of the file to send.
+        filename: The filename (e.g. 'report.txt', 'data.csv').
+        caption: Optional caption to display with the file.
+    """
+    adapter = messaging._adapter
+    if adapter is None:
+        return 'No channel adapter configured.'
+    if not hasattr(adapter, 'send_document'):
+        return 'Channel adapter does not support file sending.'
+    file_bytes = file_content.encode('utf-8')
+    msg_id = adapter.send_document(file_bytes, filename, caption)
+    return f'File "{filename}" sent (id={msg_id})' if msg_id else f'File "{filename}" sent'