Interactive prototypeHealthcare data
ProspectRX
NPI Lookup Tool
A healthcare data utility that appends National Provider Identifier records to uploaded CSV or Excel files using the public NPPES API.
- React
- TypeScript
- Express
- NPPES API
Marketing × AI Systems
Joel Castillo.
I write about what I build.
88% of B2B companies use AI. 6% see real ROI. The gap isn't the tools — it's the workflow.
I've spent 15 years in marketing and 2 years building multi-agent systems that close that gap for real clients with real budgets. This is where I document what actually works — the frameworks, the failures, the exact systems — in public.
Agentic SystemsContent MultiplicationWorkflow DesignHuman-AI CollaborationMarketing ArchitectureAI ROI
Wired Conscious.
One email a week. I break down one AI workflow I've actually built — exact steps, real numbers, no fluff. Then I send it to your inbox and go back to building.
If you want tool reviews and trend roundups, there are a thousand newsletters for that. This one is for the people who are done shopping and ready to redesign.
~1,200 words · Weekly · Free forever
No hype. Unsubscribe anytime. I won't be offended.
Selected work
Products I've built.
Working software built around real workflows—not concept screens or AI-generated pitch decks.
Interactive prototypeMarketing operations
UTM Campaign Builder
Campaign URL Generator
A campaign operations prototype that combines rule-based UTM validation with AI-assisted draft generation, bulk workflows, and optional campaign history.
- UTM governance
- Bulk campaigns
- History
- Promotional URLs
Interactive prototypeData operations
Data Parser
Data Preparation Workflow
A self-service prototype that transforms inconsistent provider, customer, and CRM files into normalized CSV exports mapped to a defined schema.
- CSV / TSV
- Heuristic detection
- Chunked processing
- Export profiles
What I write aboutFour pillars.
Four pillars.
One through line: the workflow.
Everything I write connects back to the same argument — workflow redesign is the difference between the 6% and everyone else. These are the lenses I use to explore that.
Agentic Marketing Architecture
Most teams try to bolt AI onto the workflow they already have. That’s why it doesn’t move the needle. I write about how to redesign the workflow first — then build the agents around it.
Where the 88%/6% gap actually closes.Content Multiplication
One long-form anchor becomes 17+ channel-native assets through a 3-agent pipeline. Not in theory — I run this for real clients. Here’s what the system looks like, what breaks, and what compounds.
1 anchor → 17 outputs, 4 from scratch.Marketing Automation & Orchestration
No single platform solves cross-channel coordination — not HubSpot, not Salesforce, not any vendor claiming otherwise. I write about the orchestration layer that connects them, and why building it yourself is the actual moat.
The stack isn’t the moat. The layer between them is.Human-AI Collaboration
Where humans stay in the loop, where they don’t, and how to design the checkpoints that keep AI-generated work from becoming AI slop with a brand logo on it. Speed is not the goal. Precision is.
Fast and wrong is still wrong.Latest writing
View all essays →Essays & frameworks.
Why 88% of Companies Use AI But Only 6% See Real ROI
I audited a SaaS team burning $14K/month on content. Three writers. Three AI tools. 83% scratch rate. McKinsey's data told me why before I walked in the door — and it wasn't the tools. Here's what the 6% do differently, and the exact workflow change that closes the gap.
Mar 2026·8 min read·Read the essay →
Content Multiplication
1 Video → 17 Pieces: The Exact Workflow I Use With Clients
Stop creating from scratch. The anchor-out system, the 3 agents, the human checkpoints — all of it.
10 min · Mar 2026
Agentic ArchitectureHow to Design Your First Multi-Agent Marketing System
Agent roles, handoff logic, what to automate first, and where human judgment still wins.
12 min · Mar 2026
Human-AI CollaborationSpeed Without Soul Is Just AI Slop
I’ve seen teams publish 30 pieces a month and lose authority doing it. Here’s the exact difference between moving fast and moving right — and the one checkpoint that separates them.
7 min · Feb 2026
Sharp takes
The stuff I say out loud.
Observations from building AI workflows day-to-day. The kind of thing I'd say to a smart CMO over coffee — not dressed up, not hedged.
Follow on LinkedIn →01
Your content strategy isn’t broken. Your workflow is.
Most teams have good instincts about what to create. They fail at sequencing — what to create first, how to extract derivatives, when to stop starting from scratch.
Workflow02
The average marketing team owns 12 AI tools and has redesigned 0 workflows.
That’s not an AI strategy. That’s a subscription habit. The tools are there. The workflows aren’t. That’s the whole problem in one sentence.
AI Adoption03
Most teams respond to a content problem by hiring. I spent two years building the engine that makes that unnecessary.
Not because people don’t matter — because starting from scratch 19 times out of 23 is the actual waste. A 3-person team running an anchor-out workflow will consistently outpublish a 7-person team that doesn’t. I’ve measured it.
Content Engine04
Somewhere right now, a CMO is approving a $200K MarTech purchase because a vendor demo used the word “agentic.”
The word is real. The hype is not. Agentic systems work — but only when they’re built around redesigned workflows. Bolted onto broken ones, they’re just expensive automation.
Agentic AI05
Speed without soul is just AI slop.
The teams that win with AI aren’t publishing faster. They’re publishing with more precision — more of the right things, for the right ICP, with a human POV that AI can’t fabricate.
Human-AIWant someone to build it for you?
If you'd rather have someone build it than read about it.
XP Gurus is where I take everything I write about here and build it for clients — content engines, agentic systems, and workflow redesigns from the ground up. SaaS and B2B companies only. Engagements start with a 90-day audit.
XP GurusContent services · Agentic systems
Visit XP Gurus ↗