Inbox agents that reply like your best rep, in under 5 minutes.
Every reply in your Unified Inbox gets read, classified, and answered by an agent trained on your offer. It handles questions and objections, proposes real meeting times, follows up when a thread goes quiet, and sends from the same mailbox or profile the prospect replied to.
- 50 free replies
- Unlimited agents on every plan
- All languages and time zones
Inbox agent · Acme Outbound
Jordan Meyer 
via Email Bison We looked at something similar last year and it was too expensive. What makes you different?
Not an autoresponder. A rep that never sleeps.
An inbox agent is built from your knowledge, your reply logic, and your rules. Then it works every reply, around the clock.
Trained on your business, not the internet
Each agent gets a knowledge base: your offer, value propositions, pricing guidance, FAQs, and case studies. Paste your website and Underfive drafts the company description for you. Replies cite what you sell, not generic filler.
Two agents on every reply
An Understanding Agent reads the whole thread, classifies the intent, scores the sentiment, and detects the language. A Drafting Agent then writes the response in your voice. Classification is half a credit, drafting is one.
Same sender, every tool
Replies go out through the tool the reply came from, whether that is Email Bison, Smartlead, Instantly, PlusVibe, HeyReach, or Gmail, from the same mailbox or LinkedIn profile. The prospect sees one continuous thread from one person.
You set the guardrails
Decide which reply categories send automatically and which wait for approval. Add CC and BCC rules per category. Scope an agent to a whole workspace, to trigger keywords, or to specific LinkedIn senders.
Inside one reply
Four stages, under five minutes, no human in the loop unless you want one.
Read
The agent gets the full thread from your sending tool, including your original email and every reply, plus the lead fields you already have.
Classify
The Understanding Agent assigns a category such as Interested, Pricing question, Objection, or Not right now, scores the sentiment, and notes the language and time zone.
Draft
The Drafting Agent writes a reply from your knowledge base and reply logic, in your tone, in the prospect's language. Interested leads get real times from your calendar.
Send or route
Auto-send categories go out in under five minutes from the same sender. Approval categories wait in your queue, in the app or in Slack. CC and BCC rules apply per category.
Inbox agent vs the alternatives
Autoresponders are fast and dumb. Copy-pasting into a chatbot is smart and slow. An inbox agent is both fast and informed.
| Capability | Auto-responder | Chatbot copy-paste | Inbox agent |
|---|---|---|---|
| Reads the full thread and your original pitch | — | ||
| Knows your offer, pricing guidance, and case studies | — | — | |
| Replies in under 5 minutes, 24/7, without a human | — | ||
| Classifies intent and sentiment before replying | — | — | |
| Handles objections and answers questions | — | ||
| Proposes real calendar times and sends the invite | — | — | |
| Follows up when the thread goes quiet | — | — | |
| Sends from the original mailbox or LinkedIn profile | — | ||
| Per-category approval, CC and BCC rules | — | — |
One agent per client, per offer, or per sender.
Agents are unlimited, so you can shape them around how you sell. Agencies run one per client workspace. Teams with several offers route by keyword. LinkedIn teams train one per sender.
See how agent modes workWorkspace level
One agent handles every reply in a workspace. Turn on the Workspace Agent and it replies to every positive reply without trigger keywords. Best for one workspace per client.
Trigger keywords
Several offers in one workspace? Route replies to the right agent by a brand name, product name, or domain in the thread.
Sender level
On LinkedIn tools such as HeyReach, Aimfox, Expandi, and GetSales, pick which sender accounts each agent replies for and train it per sender.
Inbox agents FAQ
What is an inbox agent?
An inbox agent is the AI worker inside the Underfive Unified Inbox that reads a reply, classifies it, writes a human-like response from your knowledge base, and sends it from the same sender in under 5 minutes. You can run one agent per workspace, per offer, or per LinkedIn sender.
How does the agent know what to say?
From the knowledge base and reply logic you set up: company details, value propositions, pricing guidance, FAQs, case studies, and instructions for how to handle each reply category. You can auto-generate the company description from your website and edit everything afterwards.
Will it sound like a bot?
The Drafting Agent writes in the tone you set and references the actual thread and your actual offer. It does not send templates. Replies are short, specific, and answer what the prospect asked. You can review drafts before launch and keep any category on approval.
Which languages and time zones does it handle?
All of them. The agent replies in the language the prospect wrote in and proposes meeting times in their time zone.
What happens with a reply it cannot classify?
It goes to the approval queue as Uncategorized. Nothing is sent until a human approves it. You can clear the queue from the app, from Slack, or through the MCP connector.
Does it replace my sending tool?
No. Your sequencer keeps sending, warming up, and rotating. The agent only acts after a reply lands, and sends back through the same tool so threading and deliverability are unchanged.
How many agents can I create?
Unlimited. Every plan includes unlimited inbox agents and team members. You pay per reply handled, not per agent or seat.
What does a reply cost?
Understanding a reply costs half a credit and drafting a reply costs one credit. Auto-invites for booked meetings cost nothing. Start with 50 free replies and no credit card.
Your first agent takes five minutes to build.
Paste your website, connect your sending tool, and watch the first reply get handled. 50 replies free, no credit card.