Let's build a Coding Agent Harness from Scratch (Step by Step, No frameworks)

In this video, we build a feature rich coding harness by taking the best parts of Claude Code, Codex, Opencode, Pi, etc. Ego Lite Browser: https://link.ego.app/avb-fj. Git repo: https://github.com/avbiswas/neural-code Github repo for this tutorial. Everything is built from scratch, one step at a time! Follow me on Twitter: https://x.com/neural_avb To join our Patreon, visit: https://www.patreon.com/NeuralBreakdownwithAVB Members get access to everything behind-the-scenes that goes into producing my videos - including code. Plus, it supports the channel in a big way and helps to pay my bills. Content: 0:00 - Intro 1:17 - Basic Chat 2:57 - Using Bash Tool 6:26 - Accessing Browser 10:59 - Reading files 12:29 - Agentic Loops 15:08 - Design around prefix caches 18:33 - Skills 24:15 - Solving Wordle in our harness 26:34 - Advanced: Late Prompt Injection 29:23 - Advanced: TODO & Plans 31:44 - Advanced: Sandboxes and Permissions 36:50 - Advanced: Compaction 39:20 - Advanced: More Capping and Context Tricks 41:56 - Advanced: Subagents 45:38 - A Boids Simulation with DeepSeek-V4 Flash