Tonkotsu

GStack is an open-source Claude Code workflow system created by Y Combinator CEO Garry Tan, designed to encode specialized AI roles for planning, code review, QA, and shipping. Built with Bun and Playwright, it uses route-aware QA and structured release workflows to connect code changes with actual application behavior. Enables developers to achieve 10,000+ lines of quality code per week.

Cursor Composer 2 is an advanced agentic coding model built into the Cursor IDE, released March 19, 2026. With a 200,000-token context window, it autonomously plans and executes complex, multi-file coding tasks across an entire codebase — handling file edits, terminal operations, and tool use at frontier-level performance. It is used by over 50,000 businesses including Stripe.

Kilo Code is an open-source AI coding agent for VS Code, JetBrains, and CLI that generates code from natural language, automates complex tasks, and runs terminal commands. It supports 500+ AI models at provider rates and features an Orchestrator mode that breaks complex tasks into coordinated subtasks across planner, coder, and reviewer agents. With 1.5M+ users and 25T+ tokens processed, it's the #1 coding agent on OpenRouter.

Jules is Google's autonomous AI coding agent that asynchronously handles software development tasks so developers can focus on what they love. It reads your codebase, writes tests, fixes bugs, builds features, and integrates with GitHub, providing audio changelogs of its work.

Cognition AIs autonomous AI software engineer released February 24, 2026. The major update features multi-agent operation capability where AI agents dispatch tasks to other agents, plus self-assessed confidence evaluation that asks for clarification when unsure.

Goose is an open-source AI coding agent developed by Block (formerly Square) that performs multi-step software tasks autonomously in your terminal. It supports any LLM provider — including Claude, Codex, and Gemini via ACP (Agent Client Protocol) — and offers macOS sandboxing, MCP extension support, and a rich CLI for automated development workflows.