Explore AI
Harnesses
The model is the engine. The harness is the car — and it matters more than the engine does.
Every figure checked against GitHub 2026-09-22 45 days ago · worth re-checking
The short version
Of the 12 coding agents and assistants checked, 9 are actively maintained, 1 has not been committed to in months, and 2 are archived.
One well-funded commercial product fell outside the table entirely: Sourcegraph Cody, whose repository now returns a 404. It is not counted above, because there is nothing left to measure.
The most-starred tool in the list is one you have probably never heard of.
| Tool | Stars | Licence | Last commit | Status |
|---|---|---|---|---|
| opencodeTerminal agent | 209,369 | MIT | 2026-09-22 | active |
| Claude CodeTerminal agent | 147,627 | proprietary | 2026-09-22 | active |
| Codex CLITerminal agent | 125,948 | Apache-2.0 | 2026-09-22 | active |
| Gemini CLITerminal agent | 107,129 | Apache-2.0 | 2026-09-22 | active |
| ZedEditor with agent | 90,722 | NOASSERTION | 2026-09-22 | active |
| OpenHandsAutonomous agent | 88,846 | MIT | 2026-09-22 | active |
| ClineEditor extension | 69,057 | Apache-2.0 | 2026-09-22 | active |
| GooseLocal agent | 54,557 | Apache-2.0 | 2026-09-22 | active |
| AiderTerminal agent | 49,117 | Apache-2.0 | 2026-05-22 | quiet |
| ContinueEditor extension | 35,993 | Apache-2.0 | 2026-09-22 | active |
| Roo CodeEditor extension | 24,299 | Apache-2.0 | 2026-05-15 | archived |
| GitHub CopilotEditor integration | 9,966 | MIT | 2026-05-20 | archived |
What a harness actually is
A model on its own produces text. A harness is the program that puts that text to work: it reads your files, runs commands, looks at what happened, and tries again. It is the difference between asking someone for advice and handing them the keyboard.
This matters more than the model choice, and it is the least discussed part of the whole field. The same model inside a good harness will outperform the same model in a chat box by a wide margin — because the harness supplies tools, memory of the task, and the ability to check its own work.
This category churns faster than any other
Every number on this page is a real measurement from the GitHub API, including the last-commit date — and that date is the column to read. At the time of checking:
- Roo Code is archived. A popular fork of Cline, ended.
- Sourcegraph Cody has gone — the repository returns a 404.
- Aider's last commit was months ago. Not dead, but no longer moving fast.
- The Stable Diffusion web UI is roughly six months stale, superseded by ComfyUI.
None of that makes those tools bad. It means a harness is a commitment to something that may not exist in two years, and that the abundance of choice is partly an illusion — most of these will not be here.
Prefer a harness that lets you bring your own model, and that keeps your work in files you control — your repository, your git history. If the tool disappears, you keep everything that mattered. That single criterion rules out very little here and protects you from all of it.
How this was checked
Every figure on this page was read from the GitHub API on 2026-09-22, not from memory or from a vendor's own claims. Specifically:
- Stars — the repository's stargazer count, at the moment of the check.
- Licence — the licence the repository declares. "none" means it declares none, which is not the same as being unlicensed by accident.
- Last commit — the date of the most recent push. This is the column that matters most, and the one no comparison table usually shows.
- Archived — GitHub's own flag, set by the maintainer. An archived repository is read-only.
Why the last-commit column is the point. Star counts are cumulative and never fall — a project that died in 2024 still shows every star it ever earned. Only the commit date tells you whether anyone is still home.
Reproduce it yourself: node fetch-harnesses.mjs && node build.mjs --site=ai.
The script and the raw output are in the repository.
If you only try one
Install opencode or Gemini CLI — both are permissively licensed, both are actively developed, and Gemini CLI has a free tier that makes experimenting cost nothing. Point it at a small task in a repository you do not care about, and watch what it does before you trust it with anything.