AutoHarness 🤖 Agent Open source

What it does

Autoharness is a Claude Code plugin that writes and maintains skills for you, based on the work you actually do. It watches your sessions through hooks and counts tool calls. Once a session has done enough real work, a background reflection looks at what happened and decides whether a new skill is worth keeping. It can also merge the lesson into an existing skill, patch a skill, or drop it. Over time it archives skills that never get used, so the folder does not fill up with near-duplicates. It only touches skills it created itself; skills you wrote or installed are left alone.

What is inside

• Capture hooks that record each turn, redact it, and trigger reflection after a set number of tool calls
• A reflector that proposes adds, merges and patches but has no write access of its own
• A promoter that checks each proposal and is the only part allowed to write into .claude/skills/
• A session-start index listing the skills it has written, grouped by category
• A per-skill ledger of why each skill was created or changed, with the evidence behind it
• A /learn command to turn the current session into a skill straight away

All timing and size limits are set with AUTOHARNESS_* environment variables.

Works with

Claude Code only. It needs python3 on your PATH and runs on Linux and macOS.

How to install

Run these inside Claude Code, then reload plugins or restart:

/plugin marketplace add tigerless-labs/autoharness
/plugin install autoharness@autoharness

Maintenance and safety

The project is MIT-licensed, actively developed, and uses only the Python standard library. Reflection runs in extra child sessions, so it uses more tokens. The more often it reflects, the more it costs. Captured windows are redacted before they are stored, but the evidence files still hold slices of real transcripts under .claude/, so check what you commit. Uninstalling the plugin leaves its skills and state on disk until you delete them yourself.

Who should use it

It suits Claude Code users who keep solving the same kinds of problems and want those lessons kept as skills without writing each one by hand. If you prefer to curate every skill yourself, or you work on Windows, it is not a good fit.