ECC

ECC is an open-source agent harness operating system, with around 289,000 stars on GitHub under the MIT license. It gives your coding agent a coordinated engineering system and toolbox: it plans before it builds, verifies with tests, reviews from a fresh context, remembers what matters, and turns wins into reusable skills.

Overview

ECC replaces the habit of rebuilding process inside every prompt. Install it once and it becomes part of how your agent works, following one loop: plan, test, implement, review, verify, remember, improve. It works best with Claude Code today, has native Codex and Qoder plugin paths, and provides adapters for Cursor, OpenCode, Gemini, Zed, GitHub Copilot, and other harnesses, with a support matrix that states feature parity honestly.

Key Features

• Seventy-one agents, 311 skills, 97 commands: Specialized agents for planning, review, build repair, security, architecture, and domain work, with skills spanning test-driven development, research, security, docs, frontend, data, machine learning, and operations.
• Hooks and memory: Runtime enforcement, session summaries, continuous learning, instincts, and context controls. The guiding rule is to optimize the context window and persist everything else.
• AgentShield security scanning: Built-in scanning for prompts, hooks, MCP configuration, permissions, secrets, and agent files, so a compromised skill or config gets caught before it runs.
• Guided setup: A universal installer walks through setup with one command, inventories existing installs first, and configures Claude Code, Codex, or Kimi Code in one reviewed flow.
• Test-driven by default: The loop writes tests before implementation and verifies after it, with a fresh-context review that catches what the building agent missed.
• Cross-harness context sharing: Skills, rules, and memory move between harnesses, so switching agents does not mean starting over.
• Self-hosted model support: Self-hosted models and custom endpoints are supported, including a compute bridge for running models outside the big providers.

💳 Pricing

ECC is free and open source under the MIT license, and the project states the repository stays free forever. ECC Pro is a hosted GitHub App for private repositories, priced from $19 per seat per month, which funds the open-source work.

Who Is It For

ECC is for developers who use Claude Code, Codex, or similar coding agents every day and want their agent to follow a disciplined engineering process instead of improvising one per prompt. It suits solo builders who want consistent quality, teams standardizing how agents work, and anyone who has watched an agent lose context mid-task.