How I AI

Vibe-coding a kid-friendly AI fortune teller for your Halloween festivities | Marco Casalaina

In this impromptu Halloween special, Marco Casalaina (VP of Products for Core AI at Microsoft) demonstrates how he uses GitHub Spark to quickly build a mobile app that generates kid-friendly fortunes for trick-or-treaters. *Where to find Marco Casalaina:* LinkedIn: https://www.linkedin.com/in/marcocasalaina/ X: https://x.com/amrcn_werewolf?lang=en *Where to find Claire Vo:* ChatPRD: https://www.chatprd.ai/ Website: https://clairevo.com/ LinkedIn: https://www.linkedin.com/in/clairevo/ X: https://x.com/clairevo *In this episode, we cover:* (00:00) Intro (00:40) Marco’s Halloween fortune teller tradition (02:54) Using GitHub Spark to create a fortune teller app (04:32) Using Spec Kit for scoping out complex feature specs (06:53) Making fortunes more concrete and kid-friendly (10:20) Closing thoughts *Tools referenced:* • GitHub Spark: https://github.com/features/spark • SpecKit: https://github.com/github/spec-kit • GitHub Copilot: https://github.com/features/copilot • Cursor: https://cursor.com/ • Claude Code: https://www.claude.com/product/claude-code _Production and marketing by https://penname.co/._ _For inquiries about sponsoring the podcast, email jordan@penname.co._

CVClaire VohostMCMarco Casalainaguest

Oct 31, 2025·11m·Watch on YouTube ↗

📖 CHAPTERS

1. 1

   Haunted recording leads to a surprise Halloween vibe-code episode

   Claire opens with an impromptu “spooky” Halloween edition after their planned recording gets derailed. The goal becomes a quick, parent-friendly AI project viewers can copy for Halloween fun.

2. 2

   Marco’s Halloween tradition: the neighborhood block-party fortune teller

   Marco describes his annual role as a fortune teller at a big neighborhood Halloween block party in Piedmont, California. He sets the scene with his table setup and how kids interact with the experience.

3. 3

   How he used to do it: pre-generated fortunes on a phone

   Before building an app, Marco generated a list of fortunes ahead of time using GPT (earlier GPT-3, then GPT-4). During the event, he’d pick one at random from a notes app and perform the reading.

4. 4

   Choosing a vibe-coding tool: building it live with GitHub Spark

   Instead of just describing the idea, Marco decides to build a simple mobile app on the fly. He considers multiple tools but chooses GitHub Spark based on prior success.

5. 5

   Prompting the app and watching Spark generate PRD + UI code

   Marco issues a straightforward prompt and Spark rapidly produces a PRD and then scaffolds the UI (HTML/CSS). They frame this as modern front-end “vibe coding,” where iteration happens through prompts.

6. 6

   Why Spark: a quick detour into a previous chemistry flashcards app

   Marco explains he previously used Spark to build a flashcards app for his daughter’s honors chemistry studies (polyatomic ions). That experience builds confidence that Spark can handle a simple fortune “card” style app too.

7. 7

   From playful demo to serious builds: Marco’s SpecKit workflow

   While the fortune app finishes, Marco contrasts quick demos with “serious projects,” where he uses SpecKit to write better specifications. He describes how SpecKit asks clarifying questions and supports multiple coding assistants.

8. 8

   First run fortune: pretty, ambiguous, and not kid-optimized

   They try the generated app and read its first fortune aloud—mystical and nicely written but vague. Claire jokes that its ambiguity makes it a classic “fortune teller” line, while acknowledging they want something more kid-appropriate.

9. 9

   Iterating via prompts: one sentence, kid-friendly, more concrete and funny

   Marco refines the prompt: fortunes should be one sentence, kid-friendly, less abstract, more humorous, and avoid big words. They discuss how very young kids need ultra-simple, concrete fortunes.

10. 10

    Testing outputs: pizza-rock fortune, repetition issues, and a squirrel twist

    They generate a new fortune that’s specific and funny (pizza-shaped shiny rock), then notice repeated “rock” patterns in subsequent outputs. Marco points out the need to test and adjust prompts, ending with a silly squirrel scenario.

11. 11

    Claire’s next step: add voice for a spooky, kid-friendly fortune booth

    Claire plans to reuse the idea for her own upcoming block party, including hooking it up to voice for a spooky fortune-teller effect. They position it as a fun, repeatable Halloween tradition for the show.

12. 12

    Wrap-up and call to action

    Claire closes with standard show outro: engagement requests and where to find the podcast. They tease Marco returning for the originally planned topic in a future episode.