Harness Index Data on AI coding harnesses: benchmarks, pricing, and specs. No takes, just numbers.

About Harness Index

Harness Index is a data site about AI coding harnesses — the CLI tools (OpenCode, Claude Code, Aider, Codex CLI, Pi, 3code and a hundred others) that sit between you and the model.

We publish three things:

  1. The index — a maintained comparison table of the field: stars, language, license, BYOK support, pricing model. Updated monthly.
  2. Benchmarks — token spend and task scores on a fixed suite, with methodology and raw data published so you can check our math.
  3. Cost analysis — what a month of real agent work actually costs per harness, on the same models. The number nobody publishes.

Editorial stance

Verdicts allowed, adjectives rationed. Every claim carries a number, a date, and a source. Corrections are public.

Disclosure

This site is run by a pseudonymous maintainer who also maintains 3code, one of the harnesses covered. Content is AI-assisted; benchmarks and data are human-verified. All raw benchmark data is published — don't trust us, check us.