Available for projects

~/ai-engineer

I build AI agents that run in production, not demos.

WhatsApp agents that answer, qualify and book appointments for 40+ businesses.

See cases Get in touch

WhatsApp · AI agentagent execution

Hi! I’d like to book a cardiologist. Do you take my health plan?
rag.search → accepted plans
We do! Which day works best for you?
Thursday afternoon
calendar.slots → cardiology · 2 open
On Thursday I have 2:00 or 4:30 pm. Which one?
4:30
calendar.book ✓ · reminder → day before
Booked for Thursday at 4:30 pm! I’ll send you a reminder the day before ✓

23:47:02 wa-message-receiver ← +55 31 ••••-4821
23:47:03 agent.loop iter=1
23:47:04 → tool rag.search("health plans")
23:47:05 ✓ reply sent · 2.6s
23:47:21 agent.loop iter=2
23:47:22 → tool calendar.slots(thu, afternoon) · 2 open
23:47:23 ✓ reply sent · 1.8s
23:47:35 agent.loop iter=3
23:47:36 → tool calendar.book(16:30) ✓
23:47:36 → tool reminder.schedule(-24h)
23:47:37 ✓ booked · no human involved

Hi, I need to reschedule tomorrow’s appointment, something came up
patient.lookup → tomorrow 10:00 · dermatology
No problem! I found your appointment tomorrow at 10:00. Want to see times next week?
Yes, mornings
calendar.slots → 3 open
I have Monday 9:00, Tuesday 8:30 or Wednesday 11:00.
Tuesday
calendar.reschedule ✓ · old slot released
Done! Moved to Tuesday at 8:30 ✓

07:12:40 wa-message-receiver ← +55 31 ••••-1907
07:12:41 agent.loop iter=1
07:12:41 → tool patient.lookup(phone) · 1 appointment
07:12:43 ✓ reply sent · 2.4s
07:13:02 agent.loop iter=2
07:13:03 → tool calendar.slots(next week, morning) · 3 open
07:13:04 ✓ reply sent · 1.7s
07:13:15 agent.loop iter=3
07:13:16 → tool calendar.reschedule(tue 08:30) ✓
07:13:16 → slot mon 10:00 released
07:13:17 ✓ rescheduled · no human involved

How do I prepare for the blood test? Can I take my blood pressure pill before?
rag.search → exam preparation
It’s an 8-hour fast, water is fine. About the pill, let me check with our nursing team, ok?
handoff → nursing · high priority
I’ve passed your question to nursing. They’ll reply here shortly ✓
Thank you!

19:05:11 wa-message-receiver ← +55 31 ••••-3356
19:05:12 agent.loop iter=1
19:05:13 → tool rag.search("blood test preparation")
19:05:14 ✓ reply sent · 2.9s
19:05:14 guardrail: clinical question → human
19:05:15 → tool handoff(nursing, priority=high)
19:05:15 ai paused for this conversation
19:05:16 ✓ handoff complete
19:05:30 message → team (ai paused)

How much is a private dermatology appointment?
rag.search → price list
A private appointment is R$ 350. Want me to find a time for you?
Yes, but I can only do after 6 pm
calendar.slots → after 6 pm · 2 open
I have Tuesday 6:30 pm or Thursday 7:00 pm.
Thursday
calendar.book ✓ · funnel.move → booked
Booked for Thursday at 7:00 pm! I’ll send the address and a reminder the day before ✓

13:22:08 wa-message-receiver ← +55 31 ••••-6620
13:22:09 agent.loop iter=1
13:22:10 → tool rag.search("dermatology appointment price")
13:22:11 ✓ reply sent · 2.5s
13:22:40 agent.loop iter=2
13:22:41 → tool calendar.slots(after 18:00) · 2 open
13:22:42 ✓ reply sent · 1.9s
13:22:55 agent.loop iter=3
13:22:56 → tool calendar.book(thu 19:00) ✓
13:22:56 → tool funnel.move(lead, "booked")
13:22:57 ✓ new patient booked

reminder · appointment tomorrow 9:00
Hi! Just a reminder of your orthopedics appointment tomorrow at 9:00. Can you confirm?
I can’t make it, can we move it to Friday?
calendar.slots → Friday · 2 open
Sure! On Friday I have 10:00 or 3:00 pm.
3 pm
calendar.reschedule ✓ · tomorrow’s slot released
Done! See you Friday at 3:00 pm ✓

18:00:00 reminder.run → 14 appointments tomorrow
18:00:01 business hours ok
18:00:02 ✓ reminder sent
18:07:31 agent.loop iter=1
18:07:32 → tool calendar.slots(fri) · 2 open
18:07:33 ✓ reply sent · 1.8s
18:07:48 agent.loop iter=2
18:07:49 → tool calendar.reschedule(fri 15:00) ✓
18:07:49 → slot tomorrow 09:00 released
18:07:50 ✓ no-show avoided

My ear has been hurting for 3 days. Any ENT early tomorrow?
calendar.slots → tomorrow morning · 1 open
I have tomorrow at 8:00 with the ENT. Shall I book it? If the pain gets much worse, please go to an emergency room.
Yes, please book it
calendar.book ✓
Booked! Tomorrow at 8:00. Feel better ✓

02:14:07 wa-message-receiver ← +55 31 ••••-4418
02:14:08 agent.loop iter=1 · after hours
02:14:09 → tool calendar.slots(tomorrow, morning) · 1 open
02:14:10 ✓ reply sent · 2.7s
02:14:10 guardrail: urgent-care advice included
02:14:31 agent.loop iter=2
02:14:32 → tool calendar.book(08:00) ✓
02:14:33 ✓ booked at 2 am · no human involved

follow-up · 30-day return visit
Hi! It’s been 30 days since your endocrinology visit and the doctor asked for a follow-up. Want to book it?
Yes! Could it be Monday?
calendar.slots → Monday · 3 open
On Monday I have 8:30, 11:00 or 4:00 pm.
11:00
calendar.book ✓ · funnel.move → follow-up booked
Booked! Monday at 11:00 ✓

10:00:00 followup.claim → 6 eligible return visits
10:00:00 business hours ok
10:00:02 ✓ follow-up sent
10:14:19 agent.loop iter=1
10:14:20 → tool calendar.slots(mon) · 3 open
10:14:21 ✓ reply sent · 1.6s
10:14:33 agent.loop iter=2
10:14:34 → tool calendar.book(mon 11:00) ✓
10:14:34 → tool funnel.move(patient, "follow-up")
10:14:35 ✓ return visit recovered by follow-up

I need a receipt for yesterday’s appointment to claim it from my health plan
patient.lookup → yesterday · general practice
Found yesterday’s appointment. Receipts are issued by the front desk, so I’ll pass you to them, ok?
handoff → front desk · summary sent
Done! The front desk already knows what you need and will reply here ✓
Perfect, thanks

15:40:12 wa-message-receiver ← +55 31 ••••-8093
15:40:13 agent.loop iter=1
15:40:13 → tool patient.lookup(phone) · 1 appointment
15:40:15 ✓ reply sent · 2.2s
15:40:15 → tool handoff(front desk, summary)
15:40:15 ai paused for this conversation
15:40:16 ✓ handoff complete
15:40:29 message → team (ai paused)

Hi! How much is a flight to Lisbon in March?
Hi! Let me put a quote together. Which city are you flying from, and how many people?
Belo Horizonte, 2 adults
flights.search(CNF → LIS) → 3 options · card sent
Found round trips from R$ 4,380 per person. I sent you the options 👆
I’ll take the cheapest
funnel.move → qualified · handoff → agent
Perfect! I’ve passed you to our travel consultant to finish the booking ✓

21:30:05 wa-message-receiver ← +55 31 ••••-7710
21:30:06 agent.loop iter=1
21:30:08 ✓ reply sent · 2.3s
21:30:24 agent.loop iter=2
21:30:25 → tool flights.search(CNF→LIS, mar, 2) · 3 options
21:30:27 → tool send_media(card)
21:30:28 ✓ reply sent · 3.9s
21:30:41 agent.loop iter=3
21:30:42 → tool funnel.move(lead, "qualified")
21:30:42 → tool handoff(sales, summary)
21:30:43 ✓ lead qualified · summary sent to the team

Do you have Cancún packages in July? We’re a couple
We do! Do you prefer all-inclusive or just flight + hotel?
All-inclusive
rag.search → Cancún packages · 3 hotels sent
I have 7 all-inclusive nights from R$ 9,900 per person. I sent you the hotels 👆
We like the second one!
funnel.move → proposal · handoff → agent
Great choice! Our consultant will send you the proposal ✓

12:18:33 wa-message-receiver ← +55 31 ••••-2245
12:18:34 agent.loop iter=1
12:18:35 ✓ reply sent · 2.1s
12:18:49 agent.loop iter=2
12:18:50 → tool rag.search("cancún july all inclusive")
12:18:51 → tool send_media(3 hotels)
12:18:52 ✓ reply sent · 3.2s
12:19:10 agent.loop iter=3
12:19:11 → tool funnel.move(lead, "proposal")
12:19:11 → tool handoff(sales, summary)
12:19:12 ✓ proposal forwarded to the team

follow-up · no reply for 60 min
Hi! You asked for a Santiago quote a little while ago. Still interested? August fares are going up
Yes! But flying from São Paulo
flights.search(GRU → SCL) → 4 options
From São Paulo it’s R$ 1,890 round trip. Want me to hold that fare?
Yes please!
funnel.move → closing · handoff → agent
Done! Our consultant is already on your booking ✓

16:02:00 followup.claim → 1 eligible lead
16:02:00 24h window ok · business hours ok
16:02:02 ✓ follow-up 3/3 sent
16:04:47 agent.loop iter=1
16:04:48 → tool flights.search(GRU→SCL, aug) · 4 options
16:04:50 ✓ reply sent · 3.1s
16:05:02 agent.loop iter=2
16:05:03 → tool funnel.move(lead, "closing")
16:05:03 → tool handoff(sales, summary)
16:05:04 ✓ lead recovered by follow-up

¡Hola! ¿Cuánto cuesta un paquete a Río para 4 personas en enero?
¡Hola! Con gusto te ayudo. ¿Desde qué ciudad salen?
Buenos Aires
packages.search(EZE → GIG) → 3 options
Tengo 5 noches en Copacabana desde US$ 890 por persona. Te envié las opciones 👆
Perfecto, ¿cómo reservamos?
funnel.move → qualified · handoff → agent
¡Genial! Nuestra consultora te escribe ahora para cerrar la reserva ✓

11:03:41 wa-message-receiver ← +54 11 ••••-5530
11:03:42 agent.loop iter=1 · lang=es
11:03:43 ✓ reply sent (es) · 2.0s
11:03:58 agent.loop iter=2
11:03:59 → tool packages.search(EZE→GIG, jan, 4) · 3 options
11:04:01 → tool send_media(card)
11:04:02 ✓ reply sent (es) · 3.6s
11:04:20 agent.loop iter=3
11:04:21 → tool funnel.move(lead, "qualified")
11:04:21 → tool handoff(sales, summary, lang=es)
11:04:22 ✓ Spanish-speaking lead qualified

🎤 Voice note · 0:14
whisper → "I’d like to go to Rome in May with my mom"
What a great trip! Which city are you flying from?
Rio
flights.search(GIG → FCO) → 4 options · card sent
Found round trips from R$ 5,120 per person. I sent you the options 👆
Great, go ahead
handoff → agent · summary sent
Wonderful! Our consultant will issue your tickets now ✓

09:41:17 wa-message-receiver ← +55 21 ••••-3184 · audio/ogg
09:41:18 → tool whisper.transcribe(14s) ✓
09:41:19 agent.loop iter=1
09:41:20 ✓ reply sent · 2.9s
09:41:36 agent.loop iter=2
09:41:37 → tool flights.search(GIG→FCO, may, 2) · 4 options
09:41:39 → tool send_media(card)
09:41:40 ✓ reply sent · 3.8s
09:42:02 agent.loop iter=3
09:42:03 → tool handoff(sales, summary)
09:42:04 ✓ lead qualified from a voice note

📷 Image
vision → ad "Maldives · 7 nights"
I see you’re interested in the Maldives! When would you like to go?
Honeymoon, in November
rag.search → honeymoon packages · 2 options
Congratulations! I have 7 nights from R$ 18,500 per person. I sent you the packages 👆
We love the first one
funnel.move → proposal · handoff → agent
Great choice! Our consultant will reach out to sort out the details ✓

20:15:50 wa-message-receiver ← +55 31 ••••-9951 · image/jpeg
20:15:51 → tool vision.describe(image) ✓
20:15:52 agent.loop iter=1
20:15:53 ✓ reply sent · 3.0s
20:16:12 agent.loop iter=2
20:16:13 → tool rag.search("maldives honeymoon november")
20:16:14 → tool send_media(2 packages)
20:16:15 ✓ reply sent · 3.1s
20:16:40 agent.loop iter=3
20:16:41 → tool funnel.move(lead, "proposal")
20:16:41 → tool handoff(sales, summary)
20:16:42 ✓ lead qualified from an image

follow-up · no reply for 30 min
Hi! Did you get a chance to look at the Buenos Aires quote?
I did, but it’s too expensive
flights.search(flexible dates) → June is cheaper
I get it! In June the same trip is R$ 1,320, about 30% less. Want to see it?
Now we’re talking
funnel.move → qualified · handoff → agent
Deal! Our consultant is sending you the June options ✓

14:31:00 followup.claim → 1 eligible lead
14:31:00 24h window ok · business hours ok
14:31:01 ✓ follow-up 2/3 sent
14:33:26 agent.loop iter=1
14:33:27 → tool flights.search(GRU→EZE, flex) · 5 dates
14:33:29 ✓ reply sent · 3.3s
14:33:51 agent.loop iter=2
14:33:52 → tool funnel.move(lead, "qualified")
14:33:52 → tool handoff(sales, summary)
14:33:53 ✓ price objection handled

I need to change the name on a ticket I bought from you
rag.search → change policy
Name changes depend on the airline. I’ll pass this to our team to check, ok?
handoff → agent · ai paused
Done! Our consultant has your booking and will reply here ✓
Great, I’ll wait

17:48:03 wa-message-receiver ← +55 31 ••••-2767
17:48:04 agent.loop iter=1
17:48:05 → tool rag.search("ticket name change")
17:48:06 ✓ reply sent · 2.6s
17:48:06 → tool handoff(sales, summary)
17:48:06 label ai-inactive · 5 min pause
17:48:07 ✓ a human took over
17:48:20 message → team (ai paused)

● status · systems in production

Not portfolio projects. Systems clients rely on every day.

agent-platformAI agent platform (Kestra)
90 days
operational3 months, zero downtime
wa-message-receiverWhatsApp message receiver
7 days
operational29,062 runs · 100%
sanii-ticketingAI ticketing hub (Sanii)
90 days
operational~99 groups monitored

15k messages a day · 40+ businesses served · ~5k appointments booked

Real production numbers · updated Sep 2026

cases · 04

What I’ve shipped to production

01 · featured

Multi-tenant AI agent platform on WhatsApp

Agents that answer, qualify and book for 40+ businesses. Migrated from n8n to a code-first Kestra architecture with a custom agentic loop and GitOps deploys.

40+ businesses
90% without humans
3 months, zero downtime

kestra · python · supabase · whatsapp · openrouter

Read the case →

services

How I can help your operation

AI agents on WhatsApp

They answer, qualify, book and follow up around the clock, and hand off to your team at the right moment.

sdr · scheduling · follow-up · human handoff

what changes when the agent comes in

~30 min60 sfirst response time
100% human90%of conversations solved by the agent
no-shows−50%with automated reminders

CRM setup
Chatwoot set up with pipeline, labels, kanban and an installable app. The AI and your team on the same timeline.
chatwoot · pipeline · kanban
Migration to the official API
Your operation moves from UAZAPI or Evolution to Meta’s Cloud API without pausing support.
cloud api · coexistence · templates
Automations and integrations
Calendar, CRM, ERP and spreadsheets talking to each other, with versioned and monitored flows.
n8n · kestra · supabase · apis
AI monitoring
AI reading groups and channels and turning loose messages into tickets, alerts and reports.
classification · tickets · alerts

how it works

Four steps. Then the agent works and I keep watch.

01Call30 minutes to understand your operation and where support is losing sales.
02DiagnosisI map flows and integrations and lock scope, timeline and price.
03BuildWeekly deliveries, tested with real conversations before going live.
04OperationMonitoring, tuning and reports. I don’t ship and disappear.

Marco Fabian smiling, in a white shirt, holding a coffee mug

about

Hi, I’m Marco.

I’ve been writing software professionally since 2022. I started with Node.js APIs, moved through ERP systems and integrations, and since 2025 I’ve been building AI agents for real businesses. I’m studying Computer Science at UFMG and graduated in Full Stack Development from Trybe.

The first agents were built in n8n. As volume grew, I moved everything to a code-first architecture: Kestra, Python, Git, CI. Today I lead the AI implementation team at Clavia, where our agents serve 40+ businesses on WhatsApp. I joined as an engineer and was promoted to lead after being named Employee of the Month.

Belo Horizonte · Clavia · High.AI · Somedi.AI · NetZero · UFMG · Trybe

Download CV ↓LinkedIn ↗GitHub ↗

stack

ai & agents: agentic loops · tool calling · rag · versioned prompts · observability
llms: openrouter · claude · gemini · gpt
orchestration: kestra · n8n
languages: python · typescript · javascript · sql
data: supabase · postgres (rls) · redis · mysql · mongodb
integrations: whatsapp cloud api · waha · uazapi · chatwoot · google apis · feegow · gestãods · amigo
infra & testing: docker · github actions · hetzner · jest · pytest

Available for projects

Ready to put an agent into production?

Tell me about your operation. I reply within one business day.

Message on WhatsApp ↗Send an email

contato@marcofabian.dev

I build AI agents that run in production, not demos.

Not portfolio projects. Systems clients rely on every day.

What I’ve shipped to production

Multi-tenant AI agent platform on WhatsApp

How I can help your operation

AI agents on WhatsApp

CRM setup

Migration to the official API

Automations and integrations

AI monitoring

Four steps. Then the agent works and I keep watch.

Hi, I’m Marco.

Ready to put an agent into production?