{"slug": "the-last-mile-problem-in-agentic-development", "title": "The Last Mile Problem in Agentic Development", "summary": "A developer at KandiForge describes hitting the \"last mile\" bottleneck in agentic software development, where hundreds of AI agents can generate millions of lines of code across 20 repositories but the final 10-20% of hardening, integration and verification still falls to a small human team. The developer says adding more agent and human reviewers and testers did not fix the problem because tests were written after code integration, placing change gates too late. The account is framed as the first in a series leading up to a talk at BuildStuff15 in Vilnius this December.", "body_md": "Agents have made the first 80% of building software fast. Point enough of them at a well-defined problem, and you get working code, passing tests, and a system that looks almost done, sometimes in hours.\n\nThen you hit the last 10 to 20%.\n\nThat's where I think the biggest problem facing agentic developers lives today: getting from 80 or 90% done to 100%. Not generating code, but hardening an idea all the way to completion. Edge cases, integration seams, failure modes, the gap between \"it works in the demo\" and \"it works.\"\n\nHere's the trouble. When hundreds of agents are building your system, they produce work at a scale no human can match. That's the point. But the last mile has traditionally been human work: review, verification, judgment about what \"done\" actually means.\n\nSo you end up with hundreds of agents producing output and one person, or a small team, trying to do the finishing work for all of them. You don't have the time to do the work of the hundreds. The bottleneck isn't building anymore. It's completing.\n\nI hit this wall at KandiForge. Our agents had produced millions of lines of code across 20 repos, and I needed to ship. But how?\n\nIt wasn't a knowledge problem. I understood the requirements. I understood the architecture. What I couldn't do was work through every final detail across a codebase that size. There were simply too many of them, and each one needed the kind of attention that doesn't scale with the number of agents producing the code.\n\nThe agents had made building fast. They hadn't made finishing any faster.\n\nMy first move was the obvious one. I added more reviewers and more testers, both agents and people.\n\nThe testers used agents to write tests, but generally after the code was already integrated. So the change gates weren't in the right place. By the time a test caught something, the change was already in.\n\nI don't think anyone has fully solved this yet, myself included. We're all still working on it. That's part of why I'm writing this series: to share what we're trying at KandiForge, and to hear what's working for others.\n\nOver the next few posts, I'll share behind-the-scenes notes from how we're tackling this at KandiForge, where we build with an agent factory that follows an evidence-based SDLC across multiple repos. Some of it has worked. Some of it hasn't. I'll share both.\n\nThis series leads up to my talk at #BuildStuff15 in Vilnius this December ([@buildstuffconf](https://x.com/BuildStuffConf), [buildstuff.events](https://buildstuff.events)).\n\n**If you're building with agents: where does your last mile break down?** I'd like to hear how others are handling it.", "url": "https://wpnews.pro/news/the-last-mile-problem-in-agentic-development", "canonical_source": "https://dev.to/kentkandiforge/the-last-mile-problem-in-agentic-development-5768", "published_at": "2026-09-27 08:21:01+00:00", "updated_at": "2026-09-27 08:30:48.419274+00:00", "lang": "en", "topics": ["ai-agents", "ai-tools", "developer-tools", "mlops"], "entities": ["KandiForge", "BuildStuff15", "Vilnius"], "also_reported_by": [], "alternates": {"html": "https://wpnews.pro/news/the-last-mile-problem-in-agentic-development", "markdown": "https://wpnews.pro/news/the-last-mile-problem-in-agentic-development.md", "text": "https://wpnews.pro/news/the-last-mile-problem-in-agentic-development.txt", "jsonld": "https://wpnews.pro/news/the-last-mile-problem-in-agentic-development.jsonld"}}