Built on CLI Agents
Twill doesn’t reinvent the wheel—it orchestrates existing CLI coding agents like Claude Code and Open Code. This is intentional:- Tools developers already use: CLI agents are the same tools you use daily in your terminal. There’s no new interface to learn, and the code they produce follows the same patterns you’d write yourself.
- Optimized by AI labs: Model providers like Anthropic, OpenAI, and Google specifically train their models to excel at these CLI tools through reinforcement learning. By leveraging these agents, Twill benefits from billions of dollars of RL training rather than competing with it.
Sub-Agent Architecture
Twill uses a multi-agent system where specialized agents handle different parts of the workflow:1
Planning Agent
Analyzes your request, explores the codebase, and creates a detailed
implementation plan with a confidence score. You review and approve before
any code changes.
2
Code Agent
Implements the approved plan step-by-step. Follows existing patterns in your
codebase and adapts when reality doesn’t match the plan.
3
Verifyer Agent
Runs mechanical checks—tests, linting, type checking, and builds. Inspects
infrastructure logs to confirm services are healthy.
4
Critique Agent
Reviews logical correctness and alignment with the original goal. Analyzes
whether the changes actually solve the stated problem. If issues are found
by either verification agent, the code agent addresses them and re-runs
verification until everything passes.
Self-Verification in Sandboxes
What makes this verification loop actually work is that Twill runs your entire project inside an isolated sandbox environment. The agent doesn’t just write code it:- Starts your dev server using your entrypoint script
- Runs your test suite to catch regressions
- Manually tests UI changes using browser automation
- Calls API endpoints to verify backend changes
- Inspects logs to confirm services are healthy