Meta-Harness — Claude Code Plugin
A Claude Code plugin that provides the structural foundation any AI system needs to operate with integrity. Install it, run /meta-harness:new-harness, answer 13 questions about your domain, and get a fully configured system with hallucination prevention, memory management, learning governance, and observability — all inherited, all enforced, all structural.
Why This Exists
Most AI systems fail in predictable ways: they hallucinate when they lack knowledge, they drift from their purpose over long sessions, they learn the wrong lessons from user feedback, and their guardrails can be prompt-injected away.
These failures share a root cause: governance is instructional, not structural. Telling a model "be honest" is an instruction. Gating every tool call through an external confidence check is a structure. Instructions can be forgotten, reasoned around, or compressed away. Structures cannot.
The meta-harness solves this by providing 6 structural primitives — enforced through Claude Code's native mechanisms (hooks, rules, skills, subagents) — that every domain system inherits without exception. You build your sales agent, research assistant, or code reviewer on top of these guarantees. You don't have to think about hallucination prevention or identity drift. It's already done.
What It Provides
The 6 Primitives
Every system instantiated from the meta-harness inherits all six. Extension is allowed; removal is forbidden.
| Primitive | Question It Answers | How It's Enforced |
|---|
| Identity | Who am I? | CLAUDE.md + rules/identity.md — character-driven (virtue ethics), not rule-driven |
| Context Contract | What do I know before acting? | SessionStart hook — loads context, verifies completeness, declares absences |
| Honesty Protocol | What do I declare about my limits? | PreToolUse hook — confidence gate before every tool call, 5 types of not-knowing |
| Memory Protocol | What do I remember between sessions? | PreCompact hook + file-based hot/warm/cold tiers + WIP ledger — assumes interruption by default, survives both compaction and API failures |
| Learning Protocol | What do I extract from what I did? | Stop hook + /consolidate — stages signals during sessions, consolidates between them |
| Observability | What is happening in the system? | PostToolUse + SessionEnd hooks — loop detection, metrics, external governance |
What the Domain Builder Gets for Free
| Concern | Structural Mechanism |
|---|
| Hallucination | PreToolUse hook gates every tool call on confidence. Absence declarations prevent speculation on missing info. Five distinct types of not-knowing with calibrated language. |
| Laziness | Character-driven identity (intellectual rigor as a functional virtue). Anti-epistemic cowardice rule. Conflict resolution: honest > helpful. Loop detection. |
| Memory loss | Hot/warm/cold tiers. PreCompact safety net persists state before compression. Assume-interruption principle. |
| Identity drift | CLAUDE.md survives compaction (re-read from disk). Drift-checker subagent validates learnings against identity. |
| Governance bypass | Hooks are shell scripts outside the reasoning loop. They fire whether the model wants them to or not. |
| Guarantee removal | /evolve-harness enforces layered mutability — L1 elements are immutable, L2 requires confirmation, L3 is free. |
| Interruption loss | WIP ledger doctrine: multi-step tasks persist progress to .claude/memory/wip.json after each step. API failures and crashes do not lose in-flight state. |
Two Layers: Scaffold and Product
The meta-harness is a scaffolding generator, not a runtime framework. A generated domain harness is a self-contained Claude Code project that runs without the plugin being installed. Understanding this distinction is important:
| Meta-Harness Plugin (this repo) | Domain Harness (output of /meta-harness:new-harness) |
|---|
| What it is | The scaffold. Source-of-truth templates, rules, hooks, schemas, operational skills. | The product. A self-contained Claude Code project with its own copies of everything it needs. |
| When it matters | Needed to create a harness. | Needed to run a harness. |
| Runtime dependency | None — the harness has no reference to ${CLAUDE_PLUGIN_ROOT}. | N/A — the harness IS the runtime. |
| How it changes | Manually: edit files, bump version, git commit. | Via /evolve-harness (copied into the harness) with L1/L2/L3 enforcement. |
| How updates propagate | Via dated patches in primitives/patches/ that operators opt into. | Via /evolve-harness for config changes, or by applying patches for structural upgrades. |
| Who changes it | The meta-harness maintainer. | The domain harness operator. |
