ECC

Best for: developers who have outgrown a default Claude Code or Codex setup and want a structured harness around it.

ECC is an agent harness optimisation system built by Affaan Mustafa. Rather than replacing your coding agent, it wraps one — adding skills, instincts, persistent memory, security guardrails and a research-first development workflow. It works across Claude Code, Codex, OpenCode and Cursor, distributed through the ecc-universal and ecc-agentshield npm packages.

What makes it useful: it treats the harness as the thing worth optimising. The model writes the code, but tooling, memory and control loops determine whether that work is actually usable — ECC concentrates on the second half.

Where it falls short: it is a substantial layer of configuration on top of an agent that already works, so the payoff depends on your workflow being complex enough to justify it. The maintainers also warn explicitly about malicious re-uploads: install only from the official GitHub repository, the two named npm packages, the GitHub App, the ecc@ecc plugin slug, or ecc.tools. Unofficial mirrors are unreviewed and may contain malware.

Details: JavaScript, MIT licensed. Cross-harness.