The Two-Loop Problem AI Coding Created
Software development runs on two loops. The inner loop is where you write and test code locally. The outer loop is where CI validates it after the push.
AI coding tools supercharge the inner loop — agents can generate and iterate on code at a pace no human developer can match. But that speed creates a new problem: CI gets flooded with commits nobody has reviewed, and basic issues that a human would have caught locally now hit the pipeline at scale.
The safety net isn't broken. It's just in the wrong place.
What Chunk Sidecars Do
CircleCI's Chunk Sidecars are lightweight microVM environments that run alongside your local development workflow. They mirror your project's stack, test commands, and build system automatically — no manual config required.
Here's how it works in practice:
The key constraint: sidecars are designed to return feedback within 60 seconds, keeping validation within the built-in feedback windows that most agents operate within.
Agent-Agnostic by Design
Chunk Sidecars don't care which agent generated the code. They only care that it works before it hits your shared repository. Whether you're using Claude Code, GitHub Copilot, Cursor, or something you built in-house, the sidecar workflow stays the same.
This matters for teams running multi-agent setups or evaluating different AI tools — the validation layer stays consistent regardless of the upstream agent.
Why the Inner Loop Is Where Validation Belongs
Lightweight checks belong in the inner loop because that's where the agent is actively working. Feedback arrives while the change is still in motion, not after it's been committed and pushed.
This keeps agents iterating on clean code locally, and keeps CI focused on what it should actually be doing:
- Integration validation across the full codebase
- Security and compliance checks
- Release and deployment gates
When the validated changes coming out of the inner loop are already clean, CI becomes a confirmation layer rather than a debugging layer.
What's Next
Chunk Sidecars are available now for CircleCI customers. This is the first step toward rebalancing the inner and outer development loops — but the bigger play is what comes next: smarter merge handling, earlier conflict detection, and a complete validation path from first prompt to production.
If you're running AI-assisted development in a team context, the question isn't whether to add local validation — it's how fast you can get it running.
Key Takeaways
- Chunk Sidecars run lightweight microVMs locally, mirroring your CI stack
- Validation happens in under 60 seconds, within agent feedback windows
- Agent-agnostic: works with Claude Code, Codex, Cursor, or custom agents
- Frees CI from basic checks so it can focus on integration and release validation
- Available now for CircleCI customers