Learn Harness Engineering is a project-based course about building the instructions, tools, environment, state, and feedback systems that help AI coding agents work reliably. It is for people learning how to design and understand the surrounding systems that guide coding agents.
Borrowing it
Nothing to install: this file belongs to walkinglabs/learn-harness-engineering. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/walkinglabs/learn-harness-engineering/main/CLAUDE.mdgit clone --depth 1 https://github.com/walkinglabs/learn-harness-engineeringWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/instructions/walkinglabs/learn-harness-engineering/claude-md)<a href="https://agentmods.dev/instructions/walkinglabs/learn-harness-engineering/claude-md"><img src="https://agentmods.dev/badge/instructions/walkinglabs/learn-harness-engineering/claude-md/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/instructions/walkinglabs/learn-harness-engineering/claude-md"><img src="https://agentmods.dev/badge/instructions/walkinglabs/learn-harness-engineering/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00776 | $0.00776 |
| Opus 5.5 | $0.00310 | $0.00310 |
| Sonnet 5.5 | $0.00155 | $0.00155 |
| Haiku 4.5 | $0.00078 | $0.00078 |
Grade A, and why
learn-harness-engineering CLAUDE.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 64 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLAUDE.md
This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
Project Overview
Learn Harness Engineering is a project-based course on building reliable coding environments for AI agents. The repo contains a VitePress documentation site plus hands-on project code.
Commands
# Documentation site
npm install
npm run docs:dev # Dev server with hot reload (VitePress)
npm run docs:build # Production build
npm run docs:preview # Preview built site
# Run lecture code examples
npx tsx docs/en/lectures/<lecture-dir>/code/<file>.ts
# Project Electron apps (from each project directory)
cd projects/project-NN/starter # or solution/
npm install
npm run dev # Build + launch Electron (via scripts/dev.js)
npm run check # Type-check both tsconfig.json and tsconfig.node.json
npm run test # Vitest run (single run)
npm run test:watch # Vitest watch mode
Repository Structure
docs/— VitePress documentation site (lectures, projects, resources)docs/.vitepress/config.mts— Nav/sidebar config for all 15 locales (en, zh, zh-TW, ja, ko, es, fr, ru, de, ar, vi, uz, tr, uk, pt-BR)docs/<lang>/lectures/— 14 lectures, each withindex.md+code/examplesdocs/<lang>/projects/— 8 project descriptionsdocs/<lang>/resources/— localized templates, references, OpenAI advanced packdocs-readme/— localized README translations (one directory per locale)projects/shared/— Shared Electron + TypeScript + React foundationprojects/project-NN/— Per-projectstarter/andsolution/directories (project-01 through project-06; project-07 and project-08 are docs-only so far)
Architecture
The course revolves around an Electron knowledge-base desktop app that evolves across the projects:
- Main process (
src/main/): Window management, IPC handlers, service initialization - Preload (
src/preload/): contextBridge exposing typed API to renderer - Renderer (
src/renderer/): React UI with document list, Q&A panel, status bar - Services (
src/services/): DocumentService, IndexingService, QaService, PersistenceService - Shared types (
src/shared/types.ts): Cross-boundary interfaces and IPC channel constants
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2mo ago First seen · 64 lines · 776 tokens per session scan A b5a3ee4fdd55
learn-harness-engineering CLAUDE.md is an instructions file published in the GitHub repository walkinglabs/learn-harness-engineering (23,320 stars, last pushed 15d ago), licensed MIT. It adds 776 tokens to every session, about $0.0031 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
learn-harness-engineering CLAUDE.md compared with instructions from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| learn-harness-engineering CLAUDE.mdwalkinglabs/learn-harness-engineering | Instructions file | 23k | 15d ago | MIT | A | 776 | Claude Code |
| vscode buildNext.instructions.mdmicrosoft/vscode | Instructions file | 195k | today | MIT | A | 9,719 | GitHub Copilot |
| next.js AGENTS.mdvercel/next.js | Instructions file | 143k | today | MIT | A | 7,461 | Codex, OpenCode |
| vscode oss-third-party-notices.instructions.mdmicrosoft/vscode | Instructions file | 195k | today | MIT | A | 5,516 | GitHub Copilot |
| langchain AGENTS.mdlangchain-ai/langchain | Instructions file | 149k | today | MIT | A | 4,680 | Codex, OpenCode |
| vscode copilot-instructions.mdmicrosoft/vscode | Instructions file | 195k | today | MIT | A | 3,093 | GitHub Copilot |
| deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness | Instructions file | 274k | 2d ago | MIT | A | 4,313 | Codex, OpenCode |