harness-core

claude-harness

🇯🇵 日本語版 README はこちら

Operational harness for Claude Code, distilled from 6+ months of self-hosted production use.

Why a "harness"? LLM agents fail in patterned ways — credential leaks, recovery loops, premature script generation. Behavioral rules in CLAUDE.md catch some of these, but the same incidents repeat. This marketplace ships structural fixes (hooks, guards, reflexive context injection) that don't rely on the agent remembering.

Plugins

Plugin	What it does	Trigger
harness-core	3 hooks: credential value scrub (PostToolUse) + dangerous bash guard (PreToolUse) + admission-keyword workflow reminder (UserPromptSubmit)	Every Bash call + every user prompt

More plugins are planned (formation skill for long-running tmux pane workers, CLAUDE.md persona templates) — see docs/ROADMAP.md once published.

Install

# in Claude Code
/plugin marketplace add github:hrmtz/claude-harness
/plugin install harness-core@claude-harness

After install, Claude Code auto-wires the hooks via ${CLAUDE_PLUGIN_ROOT}/hooks/hooks.json. No manual ~/.claude/settings.json edit needed.

Verify install

# trigger credential scrub: paste a fake key into a Bash command output
echo 'sk-ant-api03-FAKE_KEY_FOR_TEST_xxxxxxxxxxxxxxxxxxxx'
# expected: hook detects pattern, sanitizes active session jsonl, emits warning

# trigger bash guard: try a forbidden pattern
sops -d secrets.enc.yaml
# expected: PreToolUse blocks with explanation

Manual install (without plugin marketplace)

If you'd rather copy the files directly:

git clone https://github.com/hrmtz/claude-harness
cp -r claude-harness/plugins/harness-core/hooks/* ~/.claude/hooks/
# then add to ~/.claude/settings.json — see plugins/harness-core/README.md

Philosophy

This marketplace is one half of a larger system. The other half is the philosophy + memory + persona doc:

• docs/CLAUDE_HARNESS_DISTILLED.md — full design rationale (3-tier memory, 真田/松岡/仗助 persona stack, SOPS 2-command rule, 8 incident timeline → structural fix)

Read that first if you want to understand why these hooks exist before installing them.

Status

• ✅ harness-core (this commit) — production-tested locally
• ⏳ harness-formation — pending public release of njslyr7 (tmux pane peer-worker daemon)
• ⏳ harness-claude-md-template — paste-able CLAUDE.md skeleton

License

MIT — see LICENSE.