by keli-wen
Agent skill for harness engineering — memory, permissions, context engineering, multi-agent coordination. Distilled from Claude Code, with Codex CLI and Gemini CLI on the roadmap. EN/ZH. Install via npx skills add.
# Add to your Claude Code skills
git clone https://github.com/keli-wen/agentic-harness-patterns-skillGuides for using ai agents skills like agentic-harness-patterns-skill.
Last scanned: 5/30/2026
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}agentic-harness-patterns-skill is an open-source ai agents skill for AI coding assistants such as Claude Code, Codex CLI, and ChatGPT, built by keli-wen. Agent skill for harness engineering — memory, permissions, context engineering, multi-agent coordination. Distilled from Claude Code, with Codex CLI and Gemini CLI on the roadmap. EN/ZH. Install via npx skills add. It has 289 GitHub stars.
Yes. agentic-harness-patterns-skill passed SkillsLLM's automated security scan — a dependency vulnerability audit plus prompt-injection heuristics — with no high-severity issues. You can read the full report in the Security Report section on this page.
Clone the repository with "git clone https://github.com/keli-wen/agentic-harness-patterns-skill" and add it to your Claude Code skills directory (see the Installation section above).
Yes. SkillsLLM lists many other AI Agents skills you can browse and compare side by side. Open the AI Agents category from the badge at the top of this page, or use the Related Skills and comparison links further down to weigh agentic-harness-patterns-skill against similar tools.
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[!TIP] How this was built: Read the Distilling Claude Code Source — A Harness Engineering Practice Log for the full story of how Codex and Claude Code collaborated, the PCA-inspired taste injection, and what worked (and didn't).
The model loop is easy. User -> LLM -> tool_use -> execute -> loop fits on a napkin. What makes a production agent actually work — reliably, safely, at scale — is everything around the loop: memory that persists across sessions, permissions that fail closed, context budgets that don't explode, multi-agent coordination that doesn't collapse into chaos, and extensibility that doesn't become a security hole.
Anthropic calls this the harness. This repo teaches you how to build one.
[!NOTE] This skill is compatible with the open agent skills ecosystem. Install with
npx skills add— works with Claude Code, Codex, and 40+ other agents.
6 design-pattern chapters and 11 deep-dive references, extracted from systematic source-level analysis of the Claude Code runtime — the production AI coding agent behind Claude's 512,000-line TypeScript codebase.
[!IMPORTANT] This is not a code dump or a source mirror. Every pattern is expressed as a portable, runtime-agnostic design principle. Claude Code is used as grounding evidence, not as the only possible implementation. If you're building an agent on a different stack, these patterns still apply.
Also not: A Claude Code user guide / prompt engineering tutorial / "agents 101" / model selection guide.
Engineers building or extending:
| # | Pattern | The Problem It Solves | Key Insight |
|---|---|---|---|
| 1 | Memory | "My agent forgets everything between sessions" | Separate instruction memory (human-curated) from auto-memory (agent-written) from session extraction (background-derived). Each has different trust, persistence, and review needs. |
| 2 | Skills | "I re-explain workflows every conversation" | Skills are lazy-loaded instruction sets. Discovery must be cheap (~1% of context window); full body loads only on activation. Front-load trigger language — tails get truncated. |
| 3 | Tools & Safety | "I want tools powerful but not dangerous" | Default to fail-closed. Concurrency is per-call, not per-tool. The permission pipeline has side effects — it tracks denials, transforms modes, and updates state. |
| 4 | Context Engineering | "My agent sees too much, too little, or the wrong thing" | Four operations: select (just-in-time loading), write (the learning loop), compress (reactive compaction), isolate (delegation boundaries). |
| 5 | Multi-agent | "I need parallelism without chaos" | Three patterns: Coordinator (zero-inheritance), Fork (full-inheritance, single-level), Swarm (flat peer roster). The coordinator must synthesize, not delegate understanding. |
| 6 | Lifecycle | "I need hooks, background tasks, startup sequence" | Hook trust is all-or-nothing. Task eviction is two-phase. Bootstrap is dependency-ordered with trust as the critical inflection point. |
[!TIP] Each pattern includes: Problem -> Golden Rules -> Start Here (actionable first step) -> Tradeoffs -> Gotchas -> Claude Code Evidence. Start with the "Choose Your Problem" table in SKILL.md.
11 reference documents, each following the same structure: Problem (universal) -> Golden Rules (portable) -> Implementation Patterns (no code) -> Gotchas -> Claude Code Evidence (natural language).
| Reference | Covers |
|---|---|
| memory-persistence-pattern | Four-level instruction hierarchy, four-type auto-memory, background extraction with mutual exclusion |
| skill-runtime-pattern | Four-source discovery, YAML frontmatter contract, budget-constrained listing, graceful degradation |
| tool-registry-pattern | Fail-closed builder, per-call concurrency, partition-sort-concatenate for cache stability |
| permission-gate-pattern | Single gate, three behaviors, strict layered evaluation, atomic claim for race-safe resolution |
| agent-orchestration-pattern | Mutual exclusion of modes, fork cache optimization, flat swarm topology, tool filtering layers |
| context-engineering | Index: select / compress / isolate sub-pattern routing |
| select-pattern | Promise memoization, three-tier progressive disclosure, manual cache invalidation |
| compress-pattern | Truncation with recovery pointers, reactive compaction, snapshot labeling |
| isolate-pattern | Zero-inheritance default, single-level fork boundary, worktree-based filesystem isolation |
| hook-lifecycle-pattern | Single dispatch, all-or-nothing trust, six hook types, exit-code discipline |
| task-decomposition-pattern | Typed prefixed IDs, strict state machine, disk-backed output, two-phase eviction |
| bootstrap-sequence-pattern | Dependency-ordered init, trust-split env vars, memoized concurrent callers, fast-path dispatch |
[!NOTE] Not by reading docs or guessing from external behavior.
For the full story — how Codex and Claude Code collaborated, the handoff protocol, what worked and what didn't — see Distillation Process.
[!TIP] Two skills available:
agentic-harness-patterns(English) andagentic-harness-patterns-zh(Chinese). Install via the Vercel Skills CLI — works with Claude Code, Codex, and 40+ other agents.
npx skills add github:keli-wen/agentic-harness-patterns-skill
Just reading: Open SKILL.md (EN) or SKILL.md (ZH).
agentic-harness-patterns/
├── README.md # This file (EN)
├── README_ZH.md # 中文版
├── LICENSE
└── skills/
├── agentic-harness-patterns/ # English skill
│ ├── SKILL.md
│ ├── metadata.json
│ └── references/ # 11 deep-dive documents
│ ├── memory-persistence-pattern.md
│ ├── skill-runtime-pattern.md
│ ├── permission-gate-pattern.md
│ ├── agent-orchestration-pattern.md
│ ├── tool-registry-pattern.md
│ ├── hook-lifecycle-pattern.md
│ ├── task-decomposition-pattern.md
│ ├── bootstrap-sequence-pattern.md
│ ├── context-engineering-pattern.md # Index → 3 sub-files
│ └── context-engineering/
│ ├── select-pattern.md
│ ├── compress-pattern.md
│ └── isolate-pattern.md
└── agentic-harness-patterns-zh/ # 中文 skill
├── S