Three fixes from beta tester session feedback:
1. MCP error handling (backend/app/services/assistant_chat_service.py)
- The MCP Microsoft Learn integration was catching only BadRequestError.
Any other error type (APIStatusError, APIConnectionError, timeout) from
the external MCP server propagated as a 502, causing the generic error.
- Now catches all Exception types when MCP is active and retries without
MCP using the stable client.messages.create endpoint.
2. Frontend error UX (frontend/src/pages/AssistantChatPage.tsx)
- catch {} was silently swallowing all errors and inserting a generic
assistant message. Now: differentiates 429 (rate limit) vs 502/503
(AI unavailable), removes the optimistic user message on failure,
restores the failed message to the input so users can retry without
retyping, and logs errors to console for debugging.
3. Image attachments visible in chat (frontend/src/components/assistant/ChatMessage.tsx)
- Uploaded images were sent to the AI correctly but never shown in the
chat thread. Now captures preview URLs before clearing pendingUploads
and renders thumbnails above the user bubble, clickable to full size.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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