Advanced context engineering techniques and patterns for Claude Code, OpenCode, Cursor, Antigravity and more.

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Context Engineering Kit

A hand-crafted collection of advanced context engineering techniques and patterns with minimal token footprint, focused on improving agent result quality and predictability.

The marketplace is based on prompts our company's developers have used daily for a long time, supplemented by plugins from benchmarked papers and high-quality projects.

Key Features

• Simple to Use - Easy to install and use without any dependencies. Contains automatically used skills and self-explanatory commands.
• Token-Efficient - Carefully crafted prompts and architecture, preferring command-oriented skills with sub-agents over general information skills when possible, to minimize populating context with unnecessary information.
• Quality-Focused - Each plugin is focused on meaningfully improving agent results in a specific area.
• Granular - Install only the plugins you need. Each plugin loads only its specific agents, commands, and skills, without overlap or redundant skills.
• Scientifically proven - Plugins are based on proven techniques and patterns validated by reputable benchmarks and studies.
• Open-Standards - Skills are based on agentskills.io specification. The SDD plugin is based on the Arc42 specification standard for software development documentation.

News

Updates from key releases:

• v3.1.0: Improved Spec-Driven Development plugin generated code quality by embedding DDD/SOLID rules in the developer agent and adding a dedicated code-reviewer agent that applies functional and OOP best-practices rules together with Muda waste analysis to reduce code complexity and duplication.
• v3.0.0: Added support for AMP and Hermes agents. Tech Stack plugin now automatically injects typescript best practices when agent reads or writes TypeScript files.
• v2.2.0: Subagent-Driven Development plugin now works as a distilled version of SDD plugin using meta-judge and judge sub-agents for specification generation on the fly and in parallel to implementation. DDD plugin now includes Clean Architecture, DDD, SOLID, Functional Programming, and other pattern examples as rules that are automatically added to the context during code writing.
• v2.1.0: Spec-Driven Development plugin agents include high-level code quality guidelines from DDD plugin.
• v2.0.0: Spec-Driven Development plugin was rewritten from scratch. It is now able to produce working code in 99% of cases on real-life production projects!

Quick Start

Step 1: Install Marketplace and Plugins

Claude Code

Open Claude Code and add the Context Engineering Kit marketplace

/plugin marketplace add NeoLabHQ/context-engineering-kit

This makes all plugins available for installation, but does not load any agents or skills into your context.

Install any plugin — for example, reflexion:

/plugin install reflexion@NeoLabHQ/context-engineering-kit

Each installed plugin loads only its specific agents, commands, and skills into Claude's context.

Cursor, Antigravity, Codex, OpenCode and others

Run the vercel-labs/skills command in your terminal:

npx skills add NeoLabHQ/context-engineering-kit

You can pick which skills and agents to install.

Alternative installation methods

You can use OpenSkills to install skills by running the following commands:

npx openskills install NeoLabHQ/context-engineering-kit
npx openskills sync

Step 2: Use Plugin

> claude "implement user authentication"
# Claude implements user authentication, then you can ask it to reflect on implementation

> /reflect
# It analyses results and suggests improvements
# If issues are obvious, it will fix them immediately
# If they are minor, it will suggest improvements that you can respond to
> fix the issues

# If you would like to prevent issues found during reflection from appearing again,
# ask Claude to extract resolution strategies and save the insights to project memory
> /memorize

Alternatively, you can use the reflect word in the initial prompt:

> claude "implement user authentication, then reflect"
# Claude implements user authentication,
# then hook automatically runs /reflect

In order to use this hook, you need to have bun installed. However, it is not required for the overall command.

Documentation

You can find the complete Context Engineering Kit documentation here.

However, the main plugins we recommend starting with are Subagent-Driven Development and Spec-Driven Development.

Agent Reliability Engineering

The three plugins in this marketplace are designed to improve how accurately and consistently the agent follows provided instructions and to reduce hallucinations and bias toward incorrect solutions. They are not competitors but rather complementary to each other, because they allow you to balance reliability vs. token cost. Here is a high-level comparison of different agent usage approaches and the probability of receiving results that are fully accurate and include zero hallucinations, based on task complexity:

Approach	Probability of receiving fully accurate results for the following number of changed files (p)	Tokens Overhead	What does this mean in practice
1-3	4-10	10-20	20+
One-shot prompt	60%-80%	30%-50%	5%-30%	1%-20%	0	Accuracy depends on model, but with context growth LLM quality degrades exponentially
/reflect	68%-91%	49%-71%	13%-41%	1%-30%	1k-3k	Agent finds and fixes missed requirements on its own
/reflect + /memorize	79%-87%	60%-79%	34%-42%	5%-30%	2k-5k	Agent extracts repeatable mistakes and avoids them during new tasks
/do-and-judge	90%	83%	60%	30%	1.5x-3x	Mitigates context rot, bias, hallucinations and missed requirements using Judge sub-agent
/do-in-steps	92%	90%	71%	50%	3x-5x	Resolves all issues similar to /do-and-judge, but separately per file group
/plan-task + /implement-task	94%	93%	85%	70%	5x-20x	Performs the /do-in-steps flow, but the specification mitigates issues caused by inconsistent architecture and codebase size
/brainstorm + /plan-task + /implement-task	95%	95%	90%	80%	5x-20x	Brainstorming decreases the number of incorrect decisions and missed requirements
/plan-task + human review + /implement-task	99%	99%	99%	95%	5x-35x	Human review mitigates misunderstanding of requirements by LLM

Reliability metrics are based on more than year of real development usage on production projects.

Plugins List

To view all available plugins:

/plugin

• Reflexion - Introduces feedback and refinement loops to improve output quality.
• Spec-Driven Development - Introduces commands for specification-driven development, based on Continuous Learning + LLM-as-Judge + Agent Swarm. Achieves development as compilation through reliable code generation.
• Review - Introduces code and PR review commands and skills using multiple specialized agents with impact/confidence filtering.
• Git - Introduces commands for commit and PR creation.
• Test-Driven Development - Introduces commands for test-driven development and common anti-patterns, plus skills for testing using subagents.
• Subagent-Driven Development - Introduces skills for subagent-driven development, which dispatches a fresh subagent for each task with code review between tasks, enabling fast iteration with quality gates.
• Domain-Driven Development - Introduces commands to update CLAUDE.md with best practices for domain-driven development, focused on code quality, and includes Clean Architecture, SOLID principles, and other design patterns.
• FPF - First Principles Framework - Introduces structured reasoning using ADI cycle (Abduction-Deduction-Induction) with knowledge layer progression. Uses workflow command pattern with fpf-agent for hypothesis generation, verification, and auditable decision-making.
• Kaizen - Inspired by Japanese continuous improvement philosophy, Agile and Lean development practices. Introduces commands for analysis of root causes of issues and problems, including 5 Whys, Cause and Effect Analysis, and other techniques.
• Customaize Agent - Commands and skills for writing and refining commands, hooks, and skills for Claude Code. Includes Anthropic Best Practices and Agent Persuasion Principles that can be useful for sub-agent workflows.
• Docs - Commands for analyzing projects, writing and refining documentation.
• Tech Stack - Rules for language-specific best practices, automatically applied when working on matching file types.
• MCP - Commands for setting up well-known MCP server integrations when needed and updating the CLAUDE.md file with requirements to use MCP servers in the current project.

Stay ahead

Star Context Engineering Kit on GitHub to support its development and get notified about new features and updates.

Reflexion

Collection of commands that force the LLM to reflect on the previous response and output. Includes automatic reflection hooks that trigger when you include "reflect" in your prompt.

How to install

/plugin install reflexion@NeoLabHQ/context-engineering-kit

Commands

• /reflect - Reflect on the previous response and output based on the self-refinement framework for iterative improvement with complexity triage and verification
• /memorize - Curate insights from reflections and critiques into CLAUDE.md using Agentic Context Engineering
• /critique - Comprehensive multi-perspective review using specialized judges with debate and consensus building

Hooks

• Automatic Reflection Hook - Triggers /reflect automatically when "reflect" appears in your prompt

Theoretical Foundation

The plugin is based on papers like Self-Refine and Reflexion. These techniques improve the output of large language models by introducing feed