𝗖𝗼𝗺𝗺𝗼𝗻 𝗣𝗶𝘁𝗳𝗮𝗹𝗹𝘀 𝗕𝘂𝗶𝗹𝗱𝗶𝗻𝗴 𝗘𝗺𝗮𝗶𝗹 𝗔𝗴𝗲𝗻𝘁𝘀
Your email agent works in testing. Then you ship it. Overnight, the agent replies to its own messages. Customers receive the same answer three times. Conversation threads break into pieces.
These failures happen at the infrastructure level, not because of your LLM prompt.
Check these nine items before you launch:
The Infinite Loop The webhook fires when your agent sends a reply. This triggers another webhook. You create a loop. Fix: Filter the agent email address at the top of your code. Stop the process if the sender is the agent.
Duplicate Messages Networks hiccup. Your endpoint does not respond fast enough. The system sends the same notification again. Fix: Use an atomic check on the message ID. Use Redis or Postgres to ensure you process each ID only once.
Race Conditions Two workers process the same event at the same millisecond. Deduplication alone fails here. Fix: Use a per-thread lock with a 30-second limit. Check if the agent already replied inside that lock.
Truncated Data Webhooks often carry only summaries, not full bodies. Large emails might arrive as truncated events. Fix: Always fetch the full message from the API using the ID. Do not rely on the webhook payload for content.
Broken Threads Sending a reply as a new message breaks conversation grouping in Gmail or Outlook. Fix: Pass the reply_to_message_id on every response. Match replies by thread_id, never by subject line.
The Human Correction A human sends a follow-up correction seconds after their first email. Your agent replies to both. Fix: Use a 30 to 60 second cooldown. Batch consecutive messages into one reply.
The Reply Storm A logic bug causes the agent to send hundreds of emails instantly. Fix: Set a per-thread send budget. If the agent sends 3 messages in 5 minutes, stop and alert a human.
Garbage Input Spam and out-of-office replies trigger your LLM. You pay for useless inference. Fix: Use inbox rules to block bad senders or route automated mail to a different folder.
The 403 Error Trap Outbound rules can block a send. This returns a 403 error. Standard retry logic will hammer this error forever. Fix: Treat 403 as a terminal error. Do not retry it. If you get a 503, you can retry.
Boring fixes like filters, locks, and caps are what keep an agent safe.
Source: https://dev.to/qasim157/common-pitfalls-building-email-agents-and-fixes-29kg
Optional learning community: https://t.me/GyaanSetuAi