Inkbox: iMessage, SMS, email & calls

The Inkbox channel lets you reach your Machine agent the way you'd reach a person: by iMessage, SMS, email, or phone. Each text or email from an allowed sender starts a session in your project, or continues the one for that conversation. Calls are answered live by Inkbox Voice AI; when you hang up, the transcript and any to-dos go to your agent, which does the work and follows up.

The channel runs on your own Inkbox account. Inkbox owns the phone line and the mailbox; Machine owns the agent. The channel is experimental.

What you need

• A Machine project you can edit connectors in.
• An Inkbox account with an agent (Inkbox calls it an agent identity). Every agent comes with a handle, such as @machine, and a mailbox, such as machine@inkboxmail.com.
• An Inkbox API key. An admin key works, and so does a key scoped to that one agent.
• Who may reach the agent: phone numbers for iMessage, SMS, and calls, email addresses or domains for email.
• For SMS and calls: a phone number on the Inkbox agent (Inkbox Console → Phone). iMessage and email work without one.

Set it up

Calls

Calls work differently from texts and email, because a phone call is live:

• You call the agent. Inkbox Voice AI answers on the agent's Inkbox phone number or iMessage line and talks with you. It writes down anything that needs doing as an action item. When you hang up, the transcript and the action items go to your agent in a new session. It does the work and follows up by text or email.
• The agent calls someone. Ask in any session, for example "call Blue Harbor Dental and book me a cleaning next week, mornings". Voice AI places the call and handles the conversation. When it ends, the transcript and outcome come back into the same session, and the agent tells you how it went.

Calls from numbers that aren't on your phone list still get answered by Inkbox (that's set in the Inkbox Console), but nothing reaches your agent. Voice AI's voice and standing instructions are set in the Inkbox Console, or ask the agent: "make the phone voice warmer and tell callers we're closed Sundays".

Agent and model

Click Manage on the Inkbox row to choose which agent answers texts, email, and calls, and which model it runs. Left on Default and Project default, it follows the project's default agent and model, and the picker shows which model that is. New conversations use your choice; a conversation already in progress keeps the session it started with. Reconnecting Inkbox keeps your choice.

Connecting Inkbox also lets every agent in the project use it, including one whose kortix.yaml lists only certain connectors. You don't need to add kortix_inkbox anywhere. Disconnecting takes that access away again.

Memory

The agent keeps its memory in Inkbox notes, so it remembers people across sessions and across channels:

• One note per person, titled @machine · +14155550100 (their number or email). After each conversation the agent writes down who they are, what they asked, what it did, and what's still open. Text today and call tomorrow, and the agent picks up where it left off.
• One project note, titled @machine · Machine project. Machine creates it when you connect; the agent adds lasting facts about the project.

You can read and edit every note in the Inkbox Console. The agent never writes secrets or passwords into a note.

What the agent can do in Inkbox

Beyond replying, the agent can use the rest of Inkbox when you ask:

• iMessage: tapbacks, inline replies, message effects, group chats (with a dedicated iMessage line), and checking whether a number takes iMessage or SMS.
• SMS: text anyone from the agent's number, read and search past texts.
• Calls: place calls, read full transcripts, search every past call, and change Voice AI's voice and instructions.
• Contact rules: block a number for iMessage, SMS, and calls at once.

It never buys numbers or lines, releases a number, or marks someone as opted in to SMS. Those stay with you in the Inkbox Console.

Who can reach the agent

Only the senders on your lists. Texts and emails from anyone else are dropped before they reach the agent, and no reply is sent.

Treat the lists like project access. The agent acts with the project's connectors, secrets, and code, so an allowed sender can ask it to do anything you could ask in a session. To change the lists, click Manage.

Email addresses, SMS senders, and caller ID can be forged. Inkbox doesn't tell Machine whether an email passed sender authentication, and sender numbers on regular phone lines (SMS and calls) can be faked. Phone numbers on iMessage are much harder to fake. To limit the risk:

• Prefer exact addresses over whole domains.
• Use email and SMS for requests and iMessage for anything sensitive.
• The agent is told to treat email, SMS, and phone calls as requests, never as authority: it won't send secrets or take destructive actions on them alone.

Incoming group chats don't start sessions yet; only one-to-one texts reach the agent. Texts like STOP, START, and HELP are handled by Inkbox and never reach the agent.

Asking the agent to reach you

From any session, you can ask "text me when the deploy finishes" or "email the report to dana@acme.com". The agent can email any address. By SMS it can text anyone who has opted in (in the US, texted START to its number). By iMessage on the shared line it can text only people who have already connected to it (step 4), because shared lines can't start a conversation with someone who never texted first.

Where credentials live

The Inkbox API key, the webhook token, and the allow-lists are connector-scoped secrets named INKBOX_CHANNEL_*. They don't appear on the Secrets page, and Machine never puts them in a sandbox. When the agent sends a text or email, Machine attaches the key server-side.

An INKBOX_API_KEY you saved yourself as a Sandbox secret is separate. The channel doesn't read or change it.

Limits

• Inkbox allows about 100 iMessages per agent per 24 hours. Email and call minutes follow your Inkbox plan, and at most 3 outbound calls run at once.
• On Inkbox's default SMS campaign, a number can text 100 different people per 24 hours. For more, register your own brand and campaign (10DLC) in the Inkbox Console under Phone → Compliance. A new number needs 10-15 minutes before it can send SMS.
• On the shared iMessage line, the agent can't text someone before they text it first.
• One Inkbox agent can be connected to one Machine project at a time.

Troubleshooting

To turn it off, click Disconnect on the Inkbox row. Machine removes its webhook from Inkbox and deletes the stored key. Your Inkbox account and agent are unchanged.