Reply detection and intent classification
Learn how Tantra polls your mailboxes to detect replies, links them to the right campaign, and classifies each one with AI and a keyword fallback.
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Overview
When a prospect replies to one of your campaigns, Tantra detects the reply, links it to the right conversation, and works out what the prospect meant. This article explains the timing and the classification so the labels in your inbox make sense. It also explains why a reply is not instant.
How it works
Detection has two parts: finding the reply, then classifying it.
Finding the reply
Tantra checks your sending mailboxes on a repeating cycle. The check runs roughly every 30 seconds and picks up any mailbox that is due. How often a given mailbox is checked depends on how recently it last sent:
| When the mailbox last sent | How often it is checked |
|---|---|
| Within the last 3 days | About every 30 seconds |
| 3 to 14 days ago | About every 2 minutes |
| 14 to 30 days ago | About every 10 minutes |
| 30 to 90 days ago | About every 30 minutes |
| 90 or more days ago | About every hour |
| Never sent | Not checked |
So a reply to a campaign you are actively running usually appears within a minute or so. A reply to an older campaign can take longer.
When Tantra reads a new incoming message, it tries to match it to one of your outreach threads. It matches first by the conversation the message belongs to, and if that fails, it follows the reply's header trail back to a message you sent. If it cannot link the message to any of your outreach, the message is treated as not relevant and left out of the campaign inbox.
Classifying the reply
Once a message is linked, Tantra decides what kind of message it is, in this order:
- Bounce. If the message looks like a delivery failure notice, Tantra marks it a bounce and records it against the campaign.
- Auto responder. If it looks like an out-of-office or an automatic acknowledgement, Tantra marks it an auto response. Auto responses do not stop the sequence.
- Real reply. Anything else from the prospect is a real reply. Tantra marks the prospect as replied and stops sending them further steps.
For a real reply, Tantra runs a quick keyword pass to guess the tone as positive, negative, or neutral. Right after that, it runs an AI classifier for a more precise intent. The AI result only overrides the keyword guess when the AI is confident. The AI classifier never fails the pipeline: if it cannot produce an answer, Tantra keeps the keyword guess. For the full list of intents, see Reply intents explained.
The AI classifier uses your connected LLM provider. If you have not connected one, the AI step is skipped and the keyword guess stands. See Connect your own LLM provider.
The classifier reads replies in several languages, including English, Spanish, French, German, Portuguese, Italian, and Dutch, and picks matching keyword sets automatically.
What happens next
- A detected real reply moves the prospect's enrollment to a replied state and stops their remaining steps. See Enrollment lifecycle and statuses.
- The reply appears in your inbox with a classification badge and, for real replies, an intent badge.
- A bounce is recorded against the campaign so your reporting stays accurate.
- An auto response is labeled but the sequence continues, since the prospect has not actually answered.
- If a reply clearly asks to opt out, Tantra can unsubscribe the prospect automatically. See Automatic unsubscribes.
Automatic unsubscribes
Tantra can act on opt-out replies for you, controlled by two separate settings:
- Stop-word replies. When a reply contains an unambiguous opt-out phrase, such as "unsubscribe", "remove me", or "stop", Tantra unsubscribes the prospect. This is on by default.
- AI intent replies. When the AI classifier is confident a reply is an unsubscribe request, Tantra can also unsubscribe the prospect. This is off by default, because AI verdicts are a judgment call.
A merely negative reply, such as "not interested", is not treated as an opt-out on its own. See Suppression lists and unsubscribes.
Best practices
- Connect an LLM provider so replies get precise intents, not only a tone guess.
- Keep campaigns active if you want the fastest reply detection. Older mailboxes are checked less often.
- Reply to prospects on the same thread so Tantra keeps linking messages to the campaign.
Common mistakes
- Expecting instant detection. The check is periodic, so allow a short delay.
- Assuming an out-of-office stops the sequence. It does not. Only a real reply does.
- Assuming "not interested" unsubscribes the prospect. It marks the reply negative but does not opt them out by itself.
Troubleshooting
| Symptom | Cause | Fix |
|---|---|---|
| A reply is slow to appear | The mailbox is checked less often because it sent a while ago | Wait for the next cycle. Active mailboxes are checked about every 30 seconds |
| A reply is missing from the campaign inbox | Tantra could not link it to your outreach | Make sure prospects reply on the original thread, not a new email |
| Replies show only a tone, not a precise intent | No LLM provider is connected, or the AI step was skipped | Connect a provider. See Connect your own LLM provider |
| A prospect was unsubscribed after a reply | Their reply matched an opt-out phrase and auto-unsubscribe is on | This is expected. Review the setting if you want to change it |
FAQ
Why is a reply not instant?
Tantra checks mailboxes on a repeating cycle rather than the moment a reply is sent. Active mailboxes are checked about every 30 seconds.
How does Tantra know a reply belongs to my campaign?
It matches the message to your outreach thread, and if needed follows the reply's header trail back to a message you sent.
Does an out-of-office count as a reply?
No. It is labeled an auto response and the sequence keeps going.
What happens to the prospect's remaining steps after a real reply?
They stop. A real reply moves the enrollment to a replied state. See Enrollment lifecycle and statuses.
What if the AI classifier fails?
Nothing breaks. Tantra keeps the keyword tone guess and the reply still appears in your inbox.
Which languages can Tantra classify?
English, Spanish, French, German, Portuguese, Italian, and Dutch, with an English fallback for anything else.
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- Reply intents explainedUnderstand the reply intents Tantra assigns, from interested to unsubscribe request, and how they map to the tone badges in your inbox.
- Enrollment lifecycle and statusesUnderstand how a contact moves through a Tantra cold email sequence, what each enrollment status means, and how to manage enrollments.