The Vibes-Based Agent Era Deserves to End
Every agent demo you've seen this year works the same way: stuff the context window, let the model improvise, applaud the output. Ask the obvious follow-up questions and the whole edifice wobbles. Why did it read those files? It seemed relevant. Will it do the same thing tomorrow? Probably not. What happens when a document it reads contains instructions? Please don't ask that one.
We've been building agents where the model decides everything — what to load, what to trust, what to believe, what to spend — and then acting surprised that the result can't be audited, can't be reproduced, and can't be defended in front of anyone who signs things for a living.
Today kcp-agent 0.2.0 ships to npm, and it's not really a release. It's a counter-argument. It inverts the agent stack: determinism at the core, the model at the edge — on a leash. Its slogan is a falsifiable engineering claim, and CI falsifies it daily, and fails to:
The most deterministic agents in the world. Every decision defensible.
npx kcp-agent plan "how does the planner score units?" \
--manifest https://raw.githubusercontent.com/Cantara/kcp-agent/main/knowledge.yaml

![[ The Third Test Harness ] — Preventing specification drift in autonomous, AI-augmented development workflows. Terminal prompt: system_verify --target live --mode external_truth → STATUS: DRIFT DETECTED](/assets/images/blog/third-test-harness/th-hero.png)