Use when starting a new session, when agent output quality degrades, when switching between tasks, or when you need to configure rules files and context for a project.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Context Engineering
## Overview
Feed agents the right information at the right time. Context is the single biggest lever for agent output quality — too little and the agent hallucinates, too much and it loses focus. Context engineering is the practice of deliberately curating what the agent sees, when it sees it, and how it's structured.
## When to Use
- Starting a new coding session
- Agent output quality is declining (wrong patterns, hallucinated APIs, ignoring conventions)
- Switching between different parts of a codebase
- Setting up a new project for AI-assisted development
- The agent is not following project conventions
## The Context Hierarchy
Structure context from most persistent to most transient:
```
┌─────────────────────────────────────┐
│ 1. Rules Files (CLAUDE.md, etc.) │ ← Always loaded, project-wide
├─────────────────────────────────────┤
│ 2. Spec / Architecture Docs │ ← Loaded per feature/session
├─────────────────────────────────────┤
│ 3. Relevant Source Files │ ← Loaded per task
├─────────────────────────────────────┤
│ 4. Error Output / Test Results │ ← Loaded per iteration
├─────────────────────────────────────┤
…
The line at the top of this page pins the label git:20260215.9b3aa3e, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
GET https://markdownregistry.com/api/v1/artifacts/art_y67rrk5reko4fqqm
GET https://markdownregistry.com/api/v1/resolve?ref=lll0k0lad/agent-skills/context-engineering
GET https://markdownregistry.com/api/v1/blob/cf49c210d9c639246bbc08c834b5bb9c99bd2ecdbfc15343b0a8348b383618a0
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
lll0k0lad/agent-skills · skills/api-and-interface-design/SKILL.md · Use when designing APIs, module boundaries, or any public interface. Use when creating REST or GraphQL endpoints…
lll0k0lad/agent-skills · skills/browser-testing-with-devtools/SKILL.md · Use when building or debugging anything that runs in a browser. Use when you need to inspect the DOM, capture console…
lll0k0lad/agent-skills · skills/ci-cd-and-automation/SKILL.md · Use when setting up or modifying build and deployment pipelines. Use when you need to automate quality gates, configure…
lll0k0lad/agent-skills · skills/code-review-and-quality/SKILL.md · Use before merging any change. Use when reviewing code written by yourself, another agent, or a human. Use when you…
lll0k0lad/agent-skills · skills/debugging-and-error-recovery/SKILL.md · Use when tests fail, builds break, behavior doesn't match expectations, or you encounter any unexpected error. Use when…
lll0k0lad/agent-skills · skills/documentation-and-adrs/SKILL.md · Use when making architectural decisions, changing public APIs, shipping features, or when you need to record context…
lll0k0lad/agent-skills · skills/frontend-ui-engineering/SKILL.md · Use when building or modifying user-facing interfaces. Use when creating components, implementing layouts, managing…
lll0k0lad/agent-skills · skills/git-workflow-and-versioning/SKILL.md · Use when making any code change. Use when committing, branching, resolving conflicts, or when you need to organize work…
lll0k0lad/agent-skills · skills/idea-refine/SKILL.md · Refine ideas through structured divergent and convergent thinking. Use "idea-refine" or "ideate" to trigger.
lll0k0lad/agent-skills · skills/incremental-implementation/SKILL.md · Use when implementing any feature or change that touches more than one file. Use when you're about to write a large…
addyosmani/agent-skills · skills/context-engineering/SKILL.md · Optimizes agent context setup. Use when starting a new session, when agent output quality degrades, when switching…
mvschwarz/openrig · packages/daemon/specs/agents/shared/skills/process/context-engineering/SKILL.md · Use when designing, reviewing, or debugging how an agent's context window gets filled, pruned, or shared — choosing…
mvschwarz/openrig · skills/_canonical/process/context-engineering/SKILL.md · Use when designing, reviewing, or debugging how an agent's context window gets filled, pruned, or shared — choosing…
a5c-ai/babysitter · library/methodologies/gsd/skills/context-engineering/SKILL.md · Context window monitoring and budget management. Keeps orchestrator at 15-30% context usage while subagents get full…
shashankswe2020-ux/whoop-mcp · .github/skills/context-engineering/SKILL.md · Optimizes agent context setup. Use when starting a new session, when agent output quality degrades, when switching…
