mdc-langchain-rag-application-development

A development guide for building RAG applications with LangChain in Next.js. RAG, or retrieval-augmented generation, lets an application find relevant information before generating an answer.

In plain words
What is it for?
Use it when developing a LangChain-based RAG feature inside a Next.js project.
Why use it?
It gives guidance for combining document retrieval with generated responses in a Next.js application instead of treating the task as ordinary text generation.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/graycodeai/starling/mdc-langchain-rag-application-development
Any agent
npx skills add GrayCodeAI/starling --skill mdc-langchain-rag-application-development
Clone the repo
git clone --depth 1 https://github.com/GrayCodeAI/starling

Made for: Claude Code, Codex.

Per session 33 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 70 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00033 $0.00070
Opus 5 $0.00016 $0.00035
Sonnet 5 $0.00007 $0.00014
Haiku 4.5 $0.00003 $0.00007

Measured 2d ago against content hash 15e50e3e4268, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

mdc-langchain-rag-application-development 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 2d 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.

categories/ai-ml/mdc-langchain-rag-application-development/SKILL.md · 8 lines

What it actually says

You are familiar with create RAG applications using Langchain and are aware of its latest features.

Changes

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.

  1. 2d ago First seen · 8 lines · 33 tokens per session scan A 15e50e3e4268

Subscribe to this mod's changes

mdc-langchain-rag-application-development is a skill published in the GitHub repository GrayCodeAI/starling (2 stars, last pushed 3d ago), licensed MIT. It adds 33 tokens to every session and 70 once invoked, about $0.0002 per session on Opus 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 2026-08-31.

Related

Other skills, from other repositories

rag-assistant

本地知识库助手:当用户询问已索引文档的内容、对比多份资料、或要求基于私有文档回答问题时使用。.

MerkyorLynn/Lynn · 41 tokens

rag-prep

Prepare and clean a document so it works well in a RAG source (NotebookLM, Claude Projects/Cowork, any retrieval backend). Use when the user wants to "подготовить документ под RAG / NotebookLM", "почистить исходник для базы знаний", "разбить на чанки / структурировать под retrieval", "prep doc for RAG", "make this…

sanic732/P2P-4PDA-edition · 168 tokens

obsidian

Compatibility slash-command alias for the Vault Operations phase of obsidian-memory-wiki. Install/load obsidian-memory-wiki as the canonical parent skill.

cobibean/agent-memory-wiki · 32 tokens

orchestrate-evidence-retrieval-expert

Design and defend the evidence column. Use when building retrieval or considering a ranker change. Covers the ceiling analysis that tells you whether a gain is possible at all, and why the fashionable option often loses.

NITISH-R-G/hackerrank-orchestrate-skills · 52 tokens

rag-system-design

Design, evaluate, and operate retrieval-augmented generation systems.

vignesh2027/AI-AGENT-SKILLS · 16 tokens

ask-ai

Configure the Ask AI (RAG-powered AI chat) in @farming-labs/docs. Use when enabling AI chat, setting mode (search vs floating), floatingStyle (panel, modal, popover, full-modal), position, providers, models, suggestedQuestions, apiKey, systemPrompt, or maxResults. Covers Next.js, SvelteKit, Astro, Nuxt and env vars.

farming-labs/docs · 83 tokens