Systems Thinking Lab: Free Engineering Tools

Free tools from Systems Thinking Lab, installable as Claude Code plugins or, for other coding agents, as Agent Skills (see Install below). Scaffold is the workflow; design-with-blocks and review-with-blocks apply the seven building blocks (see The tools and The framework below).

Install

Add the marketplace once:

/plugin marketplace add kayashaolu/systemthinkinglab

Then install any tool:

/plugin install design-with-blocks@systemthinkinglab
/plugin install review-with-blocks@systemthinkinglab
/plugin install scaffold@systemthinkinglab

Updates later are just /plugin marketplace update systemthinkinglab.

For agents other than Claude Code:

npx skills add kayashaolu/systemthinkinglab --skill design-with-blocks
npx skills add kayashaolu/systemthinkinglab --skill review-with-blocks
npx skills add kayashaolu/systemthinkinglab --skill scaffold

Each skill lands in your project's .agents/skills/<name>/ as an Agent Skill; they are built and tested in Claude Code.

The tools

Plugin	What it does
design-with-blocks	Design an app using the 7 Universal Building Blocks: describe it in plain English, decompose features into blocks, get per-block technology recommendations, and output a buildable design doc.
review-with-blocks	Review a finished system design against the 7 building blocks and the non-functional "-ilities": decompose it, flag wrong/missing/over-engineered blocks, rate each load-bearing -ility (holds / at-risk / gap) with its tradeoff, and surface the questions a senior would ask.
scaffold	A plan-first developer workflow, run by an AI mentor: it predicts before it builds, keeps a compounding wiki of your codebase, and holds an honest ledger of what you've demonstrated you know, in craft or direction mode.

All three are free, open source (Apache-2.0), and installable by anyone. Together they cover the arc design → build → review: design-with-blocks plans the architecture, scaffold runs the plan-first workflow while you build it, and review-with-blocks judges the result. All three use the seven building blocks, free to read at systemthinkinglab.ai/learn.

The framework

Every system, from Instagram to Stripe, is built from the same seven primitives: Service, Worker, Key-Value Store, File Store, Queue, Relational Database, Vector Database; plus three external entities: User, External Service, Time. That vocabulary is the intellectual work of Kay Ashaolu, founder of Systems Thinking Lab. If you want pattern literacy, the ability to design any future system without a tool, you can learn the 7 building blocks for free at systemthinkinglab.ai/learn.