Vigyata.AI
Is this your channel?

Coding Agent Reliability EXPLODES When They Argue (New Adversarial Dev Technique)

9.2K views· 333 likes· 17:36· Mar 30, 2026

🛍️ Products Mentioned (6)

Your AI coding agents fail on complex tasks not because the model is insufficient, but because you aren't separating the planning, building, and evaluation into distinct roles. The building and evaluation agents essentially have to fight each other to get the best results. Anthropic just published a deep engineering article breaking down exactly how they solved this for multi-hour coding sessions with a GAN-inspired three-agent architecture, and the pattern is something you're going to want to try on your own codebases! But I didn't just want to explain the article. I built my own version of this three-agent harness using the Claude Agent SDK and the Codex SDK, and I'm giving it away. ~~~~~~~~~~~~~~~~~~~~~~~~~~ - Want to learn AI engineering? Scrimba's AI Engineer Path is hands-on, project-based, and very effective: https://scrimba.com/learn/aiengineer?via=colemedin - All Scrimba coding courses (many free): https://scrimba.com/courses?via=colemedin ~~~~~~~~~~~~~~~~~~~~~~~~~~ - If you're interested in building your own AI second brain to save yourself hours every week, check out the Dynamous community and upcoming 4 hour second brain workshop: https://dynamous.ai/second-brain-bootcamp ~~~~~~~~~~~~~~~~~~~~~~~~~~ - Adversarial Dev Harness (my implementation - Claude Agent SDK + Codex SDK): https://github.com/coleam00/adversarial-dev - Anthropic: Harness Design for Long-Running Application Development: https://www.anthropic.com/engineering/harness-design-long-running-apps - Anthropic: Effective Harnesses for Long-Running Agents (companion piece): https://www.anthropic.com/engineering/effective-agent-harnesses ~~~~~~~~~~~~~~~~~~~~~~~~~~ 0:00 AI's Sycophancy Problem 1:02 Adversarial Dev Solution 2:31 GAN-Inspired AI Harnesses 4:23 Harnesses Build Amazing Apps 6:49 Scrimba 8:07 Harness System Architecture 10:39 Sprint Negotiation & Evaluation 12:48 Get Started With Harness 16:01 Token Cost vs. Value ~~~~~~~~~~~~~~~~~~~~~~~~~~ Join me as I push the limits of what is possible with AI. I'll be uploading videos weekly - at least every Wednesday at 7:00 PM CDT!

About This Video

The biggest problem I’m seeing in AI right now is sycophancy: models agree with you (and with themselves) way too easily. And it hits hardest in AI coding, because the worst thing you can do is have a coding agent evaluate its own work after it’s been swimming in your opinions for an hour. It’s like a student grading their own homework—maybe it flags a couple cosmetic issues, but the real bugs and bad decisions get stuffed under the rug until your codebase is on fire. In this video I show the fix: give your builder a sparring partner. I break down Anthropic’s new GAN-inspired harness for long-running coding sessions—planner + generator + evaluator—where the evaluator’s sole job is to be nitpicky and rip apart the implementation. Then I get practical and walk through my own “adversarial dev” harness that I built from scratch (Claude Agent SDK + Codex SDK, and you can even mix them). The key is sprint negotiation before any code gets written: the generator and evaluator agree on phases, scoring criteria, and thresholds, then iterate (up to retries) until each sprint passes. Yes, it costs tokens, but the reliability boost is worth it—and it’s how you can use smaller/faster models and still ship surprisingly polished apps.

Frequently Asked Questions

🎬 More from Cole Medin