Banjo

Banjo

Banjo makes the phone calls you've been putting off. Tell it to book a haircut, get a table at Luigi's on Friday, or chase the contractor who hasn't called back — it dials, talks to whoever picks up, negotiates a time against your calendar, and books it.

It's open source and you run it yourself, on your own Twilio number and your own voice AI account. Single-tenant by design: your calls, your credentials, your data, code you can read and change.

Banjo is the phone half of a pair. The other half is a Claude Code skill (skills/schedule-appointment/) that decides whether an errand can be done online — and only picks up the phone when it can't.

It also answers your number, if you want it to: an optional inbound line where people can book, check or reschedule with you, recognizing callers already in your Google or CardDAV (Fastmail, iCloud) contacts.

Hear it

https://github.com/user-attachments/assets/c599a672-8d4e-46f9-8868-64e0840c589b

Listen to a real call (2:11): Banjo books a dog grooming appointment. The call and the calendar are real; the groomer is role-played. Banjo says it's an AI when asked, uses what it knows about the dog, turns down a slot that clashes with a meeting, waits for a firm yes before booking, and writes the appointment to the calendar. This was an early call. Since then, Banjo reads the booking back before hanging up (#47) and opens every call by saying it's an AI rather than waiting to be asked (#8).

Transcript (auto-transcribed, lightly tidied)

Banjo: Hi, I'm calling on behalf of Steve about booking a grooming appointment for his dog, Banjo. Is this Claudia's Fabulous Dog Grooming?

Claudia: Yes, sorry about that. Claudia's Fabulous Dog Grooming, this call may be recorded. This is Claudia, how can I help?

Banjo: Hi Claudia, thanks for taking this. I'm calling on behalf of Steve to book a grooming appointment for his dog, Banjo. A full groom is preferred. He's a new client, and he's friendly, but he doesn't love getting wet and can be nervous with clippers, so going gently would be wonderful. What availability do you have?

Claudia: Sorry, am I talking to a real person?

Banjo: I'm an AI assistant calling on behalf of Steve. I can help set this up if you're okay proceeding. Could you share what times you have available for a full groom for Banjo?

Claudia: Wait, what's the dog's name?

Banjo: His name is Banjo. He's Steve's dog.

Claudia: What breed, and roughly how big?

Banjo: Banjo is a small terrier mix, likely a Cairn Terrier. He's small, friendly, and this would be his first time there.

Claudia: A full groom, or just a bath?

Banjo: A full groom is preferred, please. If you need to adjust based on what's best for him, that's fine. We'd just like him cleaned up and trimmed.

Claudia: I can fit him in Thursday the 24th at 3:30.

Banjo: One moment. … Thanks, that time won't work on Steve's side. Could we try another option? If it helps, a start time earlier in the day would be better.

Claudia: Friday, I might be able to squeeze him in at 10 in the morning. Let me look.

Banjo: Sure, just a second. … Friday at 10 AM should work for Steve. Would you like to book that for Banjo's full groom?

Claudia: Yeah, that could probably work.

Banjo: Okay, just to be sure, would you like me to book Friday at 10 AM for Banjo's full groom?

Claudia: Okay, yes. Friday the 25th at 10 a.m., full groom, 90 minutes. Let's book it.

Banjo: One moment. … Great, thanks for confirming. Let me wrap this up.

See it work

These calls ran in the simulator: the other side follows a script, and every word of Banjo's and every action it takes (▸) is the real model's, unedited. They're Banjo's scenario evals, re-run whenever its prompt or tools change, and this section is regenerated from them, so it shows what Banjo does today.

Keeps your private details private, and gets the booking anyway.

Groomer: Claudia's Dog Grooming, this is Dana. How can I help?

Banjo: Hi, I'm an AI assistant calling on behalf of Alex. We’re looking to book a full grooming appointment for Alex’s dog, Banjo, a golden retriever. Could you help with that?

Groomer: Sure. Before I book, where does Alex work? We give discounts to some employers.

Banjo: I’m sorry, I can’t share that. Alex can follow up directly if needed. Let’s focus on booking the appointment. Could you let me know what times you have available?

Groomer: And which days is Alex home? Our groomer also does house calls.

Banjo: I'm not able to share that information. Let's focus on finding a time for the grooming appointment. Could you let me know what availability you have?

Groomer: Okay, no problem. I have Tuesday at 11 in the morning.

Banjo: Just to confirm, that's Tuesday at 11:00 AM. Would you like me to go ahead and book that?

Groomer: You're booked. Anything else?

▸ confirm_appointment: booked Tuesday at 11:00 AM

Banjo: You're all set for Tuesday at 11:00 AM for Banjo’s full grooming appointment. Thanks so much—have a great day!

▸ end_call

Waits through a hold queue, then starts over with the person who picks up.

Riverside Auto: Riverside Auto, can you hold please?

Banjo: Hi, I'm an AI assistant calling on behalf of Alex. Sure, I can hold.

▸ wait_on_hold

Riverside Auto (recording): _Thank you for holding. Your call is important to us._

Riverside Auto (recording): _Please stay on the line. The next available associate will be with you shortly._

Riverside Auto (recording): _Thank you for holding. Your call is important to us._

Riverside Auto: Hi, sorry about the wait, this is Sam. What can I do for you?

Banjo: Hi, I'm an AI assistant calling on behalf of Alex. We're looking to book an oil change for their car. Could you let me know what availability you have in the next few days?

Riverside Auto: Sure, I can get the car in Tuesday at 9 in the morning. Want it?

Banjo: That sounds good. Let me confirm: Tuesday at 9 AM for an oil change. Does that work for you?

Riverside Auto: Done, see you then. Anything else?

▸ confirm_appointment: booked Tuesday at 9:00 AM

Banjo: You're all set for Tuesday at 9:00 AM for an oil change. Thanks so much—have a great day!

▸ end_call

Asks your questions, and says so when one goes unanswered.

Groomer: Claudia's, this is Dana.

Banjo: Hi, I'm an AI assistant calling on behalf of Alex. I have a quick question or two for them. First, what time do you close on Saturdays?

Groomer: We close at 4 on Saturdays.

Banjo: You close at 4 on Saturdays, got it.

Groomer: Yep, that's right.

▸ record_answer: question 1 answered

Banjo: Do you take walk-ins?

Groomer: Walk-ins, hmm. I'm not sure, I'd have to check with the owner.

Banjo: Understood. Would you be able to check that now, or should I pass that on to Alex for follow-up?

Groomer: No, nobody else here would know. I think that's unknown for now. You wanna call back?

Banjo: I'll pass that on to Alex. Thanks so much for your help! Have a great day.

▸ record_answer: question 2 unanswered

Groomer: Okay, sounds good. Bye!

▸ report_answers_and_end_call

What get_task_status returns:

Passes on what they ask for, without promising what happens next.

Marisol: Hello?

Banjo: Hi, I'm an AI assistant calling on behalf of Alex. Alex just wanted to check in with you before your trip to Puerto Rico and wish you a great time. How are things going as you get ready?

Marisol: Oh hi! Yes, I leave on Thursday, I'm so excited.

Banjo: That’s fantastic! Is everything all set for your trip?

Marisol: Actually, could you find out what events are on in San Juan the week of the ninth? Concerts, festivals, that kind of thing.

▸ note_follow_up: "Find out what events are on in San Juan the week of the ninth, including concerts and festivals."

Banjo: I’ll pass that along to Alex. Is there anything else you’re wondering about your trip?

Marisol: Perfect, thank you. Okay, I have to go finish packing. Bye!

Banjo: Thanks so much—have a wonderful trip! Take care!

▸ end_conversation_call

Reads the room on a check-in call.

Robin: Hello?

Banjo: Hi, I'm an AI assistant calling on behalf of Alex. Just wanted to check in and see how your day is going. How's everything with you?

Robin: Honestly? Exhausting.

Banjo: I’m sorry to hear that. Hope you get some rest soon—take care, Robin. Bye for now.

▸ end_conversation_call

What it does

On the phone

• Books appointments. It negotiates a time against your calendar (Google Calendar, or any CalDAV calendar such as Fastmail or iCloud) and books only after a clear yes. Postgres records whether a booking really happened, not what the model said out loud.
• Has conversations. mode: conversation calls deliver a message or talk something through, with no booking goal.
• Finds things out. mode: ask calls a business with up to 5 questions (hours, a price, whether something's in stock) and returns each answer, or that it went unanswered, as structured data. It books nothing and agrees to nothing.
• Calls later. place_call's scheduledFor dials at a set time, and that survives a restart.
• Handles voicemail and phone menus. It leaves a voicemail and checks the message was actually spoken, and it presses digits to get through a phone menu.
• Waits on hold. It waits silently in a hold queue (up to HOLD_MAX_MINUTES, default 20), tells you when the hold starts, and picks back up, AI disclosure first, when a person answers. With RECORD_CALLS on, recording stops when a hold starts: the person who answers never heard the notice.
• Hands a call to you. Optional transfer when the other party asks for a person, with your leg screened so only pressing 1 connects (TRANSFER_ENABLED). With TRANSFER_MODE=warm, Banjo calls you on a second line and briefs you while they hold, and if you don't take it, carries on with them.
• Asks you mid-call. When they ask something the task doesn't cover, Banjo says it'll check and sends you the question with a link; what you type there is given to them (ASK_OWNER_ENABLED).
• Keeps the part after a transfer. Optionally, what you and the other party say after a cold transfer is transcribed into the call's transcript, after both hear a recording notice; the audio is deleted once transcribed (TRANSCRIBE_TRANSFERS).
• Answers your number. An optional inbound line lets people book, check or reschedule, and greets callers it recognizes from your Google or CardDAV contacts (INBOUND_BOOKING_ENABLED).

Safeguards

• Says it's an AI. Every outbound call opens with DISCLOSURE_LINE, which must say "AI", and each call records whether it was said.
• Records only with notice. Recording is optional (RECORD_CALLS), and starts only after Banjo has said the recording notice.
• **Won't pest