04/06 remediate some issues

app/routes/chatbot.py

@@ -42,22 +42,46 @@ def _call_groq(api_key, history, user_msg):
     The system prompt is prepended as a system message. Prior history and the
     new user message are appended in order.
 
+    History is capped at the most recent _MAX_HISTORY_TURNS turns and each
+    message content is truncated to _MAX_MSG_CHARS characters before being
+    forwarded. This prevents a malicious or runaway client from exhausting
+    the model's context window or inflating token costs.
+
     Raises requests.HTTPError or requests.exceptions.RequestException on failure.
     """
+    # ── History sanitisation ──────────────────────────────────────────────────
+    # 1. Strip create_ticket action blocks — re-sending them causes the model
+    #    to re-trigger ticket creation on every subsequent turn.
+    # 2. Cap to the most recent N turns so the client cannot inflate context.
+    # 3. Truncate each message's content to avoid per-message token blowout.
+    _MAX_HISTORY_TURNS = 20
+    _MAX_MSG_CHARS     = 2000
+
     model = current_app.config.get('GROQ_MODEL', _GROQ_MODEL)
 
-    # Strip any assistant messages containing a create_ticket action block.
-    # These should never reach the model — if they do, the model re-triggers
-    # ticket creation on every subsequent turn.
     clean_history = [
         msg for msg in history
         if not (msg.get('role') == 'assistant' and '"action": "create_ticket"' in msg.get('content', ''))
     ]
 
+    # Keep only the most recent turns after filtering
+    if len(clean_history) > _MAX_HISTORY_TURNS:
+        logger.warning(
+            f'[CHATBOT] history truncated from {len(clean_history)} to '
+            f'{_MAX_HISTORY_TURNS} turns for user_id={current_user.id}'
+        )
+        clean_history = clean_history[-_MAX_HISTORY_TURNS:]
+
+    # Truncate individual message content lengths
+    clean_history = [
+        {**msg, 'content': msg.get('content', '')[:_MAX_MSG_CHARS]}
+        for msg in clean_history
+    ]
+
     messages = (
         [{'role': 'system', 'content': _SYSTEM_PROMPT}]
         + clean_history
-        + [{'role': 'user', 'content': user_msg}]
+        + [{'role': 'user', 'content': user_msg[:_MAX_MSG_CHARS]}]
     )
     resp = requests.post(
         _GROQ_API_URL,