One Substrate, Two Renderers

I built a tool that generates demo videos from a running system, then decided not to productise it. Separately, I keep a backlog of blog posts seeded from postmortems. It took me an embarrassingly long time to notice these are the same pipeline with different output formats. The shape Both do this: source of truth → verify the claim → scrub what identifies the client → structure → publish For a video, that reads: query the production database and run the deployed models → confirm every number can be re-derived by a command → replace client identities with stable pseudonyms and prove nothing leaked → lay out scenes and narration → render an MP4. ...

August 22, 2026 · 4 min · Leandro Garcia

There Is No Sandbox for WhatsApp Coexistence

WhatsApp Coexistence is the feature that lets a business keep using the WhatsApp Business App on a phone while the same number is also connected to the Cloud API through a Business Solution Provider (BSP). Messages mirror in both directions, and the API side receives a webhook event — smb_message_echoes — every time a human replies from the app. That echo event is gold if you’re building a bot that shares a number with real staff: the bot can detect that a human has stepped into the conversation and shut up. I was building exactly that — an order-taking bot for a client whose employees answer the same WhatsApp number all day — and the handoff logic hinged entirely on those echoes. ...

July 17, 2026 · 8 min · Leandro Garcia

Hello, world

I spend my time building three kinds of things: computer-vision systems that run on cameras bolted above truck lanes, automation pipelines for small businesses that live entirely inside WhatsApp and spreadsheets, and open-source tools for AI agents. All three produce the same byproduct: hard-won lessons that only exist in private design docs and postmortems. A validation split that quietly flattered every metric. A “camera focus problem” that turned out to be a missing wire in a config. A power issue fixed by a shorter USB cable. ...

July 17, 2026 · 1 min · Leandro Garcia