Harness Score

Harness Score

Your AI coding agent is only as reliable as the harness around it. Measure that harness in seconds. Know exactly what to fix. Watch the number go up.

An AI coding agent is a model plus a harness — the context files, rules, skills, hooks, sensors, and guardrails wrapped around it. The model you rent; the harness you own. Two repositories can use the exact same model and get wildly different results, because one has a harness that catches mistakes before they ship and the other has none.

Harness Score measures that harness — across any tool. Point it at any repository using Cursor, Claude Code, Devin, Windsurf, Cline, Continue, or any other AI coding tool, and get a maturity level (L0–L4), a 108-point breakdown across six dimensions, and the precise, ranked list of what to fix next — with zero LLM calls, zero network access, and the same result every time you run it.

npx harness-score

  harness-score v1.0.0  ~/my-app

  Maturity: L2 · Guided   Score: 70/108 (65%)
  Detected: Cursor, Claude Code

  Context & Guides     ████████████████░░░░  80%  16/20 pts
  Skills & Commands    █████████████░░░░░░░  65%  11/17 pts
  Hooks & Guardrails   ░░░░░░░░░░░░░░░░░░░░   0%   0/14 pts
  Sensors & Feedback   ████████████████░░░░  80%  16/20 pts
  CI Feedback          ██████████████░░░░░░  71%  10/14 pts
  Hygiene & Safety     ███████████████░░░░░  74%  17/23 pts

  To reach L3: sensors ≥ 60%; ci ≥ 50%

Not just a score — a diagnosis. Every failed check names the file, explains what's missing, and links to the exact recipe to fix it. Every check is a filesystem fact — a file exists, parses, matches a pattern — never a judgment call and never a network request. Same repository, same commit, same score, on your laptop or in CI, forever. That's what lets you gate a pipeline on it.

Why this exists

Vibe-coding without a harness works, right up until it doesn't: an agent that rediscovers your conventions every session, rm -rfs something it shouldn't, or ships code nobody reviewed because nothing was there to catch it. The fix isn't "prompt better" — it's building the same kind of control system around an AI agent that you'd build around any other autonomous system: guides to steer it, sensors to check its work, and guardrails to stop it before damage happens.

Most repositories have none of this and don't know it. Harness Score tells you exactly where you stand, in a language a CI pipeline (and a competitive teammate) understands: a number, a level, a badge.

The maturity ladder

Levels don't just add up points — they gate on the shape of your harness. 80 points of beautifully written docs with zero tests is not maturity; it's L1. Climbing the ladder means covering a new dimension at each step.