Learn Cloudflare, Egghead and React-storybook

Hey Everyone 👋,

John Lindquist here with the second issue of AI Dev Essentials! It's been another busy week in the AI tooling world. The biggest splash was probably GPT-4.1 hitting the streets, but there's plenty more action around MCP, Vercel's v0, Google's developer tools, and interesting community discussions. I've spent some time with GPT-4.1 already (specifically in Cursor), and while it shows promise, it didn't quite convince me to switch from Gemini 2.5 Pro yet. It stumbled on a few basic requests where Gemini usually shines on the first attempt.

---

### New egghead.io Lesson This Week:

* **[Create a Custom MCP that Calls Cursor Tools](https://egghead.io/create-a-custom-mcp-that-calls-cursor-tools~r77sw):** Learn how to build custom MCP server tools that allow Cursor's AI Agent to access your local project context. This lesson shows how to use Zod schemas and the crucial `.describe()` method to explicitly request information (like Git status or version) from the Cursor environment *before* your tool runs, enabling powerful, context-aware automation.

---

Here are the highlights that caught my eye this past week.

## Model Mania: GPT-4.1 Arrives, Plus Grok & Llama Updates

* **GPT-4.1 Lands:** OpenAI announced GPT-4.1, and it quickly became available via the [API](https://openai.com/live/) and showed up in [Cursor](https://x.com/cursor_ai/status/1911835651810738406). Cursor is offering it free for now to let users get a feel for it, though they don't recommend it as a default just yet. Curious to hear initial impressions from folks testing it out for coding tasks.

* **Grok 3 in Cursor:** Following other model additions, [Cursor also enabled Grok 3 models](https://x.com/amanrsanger/status/1910434915419906141), with the mini version available for free users. Aman Sanger noted it seems to "think upfront more than other models."

* **Community Hack: Llama 4.0 via Groq in Cursor:** Levi Dan shared a [detailed (and slightly hacky) guide](https://x.com/lxvi_brg/status/1908865544721154455) on how to wire up Groq's fast Llama 4.0 API into Cursor by using the OpenAI API key slot and intercepting requests. A clever workaround for the adventurous!

## Tooling & Platform Pulse

Lots of movement across different platforms and tools this week:

* **Vercel Ecosystem:**

  * Guillermo Rauch teased [v0 coming to VS Code](https://x.com/rauchg/status/1911524154458984515), hinting at tighter integration for the UI generation tool.

  * v0 also [added AI integrations](https://x.com/v0/status/1911912183149256943) with models from xai (Grok), FAL, Groq, and DeepInfra, including automatic API key setup and pay-as-you-go billing via Vercel Marketplace. They're offering a $10 credit for the Grok free tier.

  * Vercel shared insights on the [grep.app migration from CRA to Next.js](http://grep.app/), showcasing performance improvements. ([Source](https://x.com/rauchg/status/1911920410020757881)) I'm personally excited about this one – I rely heavily on examples when working with AI, and for me, a good example is often worth ten prompts. Tools like `grep.app` that make code discovery easier are invaluable.

* **Google's Growing Stack:**

  * Project IDX has officially become [Firebase Studio](https://x.com/_davideast/status/1909990728593453455), positioning itself as a cloud-based, agentic dev environment for full-stack AI apps, deeply integrated with Firebase. I've tried spinning up a few sites with it, and the speed is impressive. However, for more complex tasks like designing from images or intricate interactions, I still find myself leaning towards v0 for now.

  * Google quietly released the [Agent Development Kit (ADK)](https://x.com/omarsar0/status/1910004370864742757), a Python library (`pip install google-adk`) for building multi-agent systems with features like state management, tool usage, and orchestration. I haven't had a chance to dive into this yet, but it's right at the top of my list. Building robust agent systems is a huge area of interest, so this is probably the announcement I'm most excited about exploring this week.

  * Ramón Medrano Llamas shared his experience [moving back to VS Code from Cursor](https://x.com/rmedranollamas/status/1909516749612999149), highlighting the effectiveness of GitHub Copilot combined with the Gemini Code Assist extension (using Gemini 2.5 Pro in Agent Mode). I gave the Gemini Code Assist extension a try myself, but as someone deeply embedded in the Cursor workflow with established keyboard shortcuts and patterns, I struggled to find a flow I liked and didn't stick with it for long. It's interesting to see different perspectives, though!

  * AI features are rolling out more broadly in [Chrome](https://x.com/iam_chonchol/status/1909942954686636224), including text grabbing from YouTube videos and Google Lens integration.

* **Cloudflare Corner:**

  * Big news for edge compute: [Cloudflare Containers are coming to Open Beta in June](https://x.com/CherryJimbo/status/1910682562499850405), enabling running containerized apps (Next.js, Go, PHP confirmed) directly on the edge. This is huge news, in my opinion. Think about all the WordPress sites and other applications that rely on containerization. Opening this up on the edge unlocks incredible possibilities, including for AI applications. I'm super hyped to see what people build with this come June.

  * A new tool, [MCPify.ai](http://mcpify.ai/), launched for building MCP servers conversationally, built entirely on Cloudflare Workers and Durable Objects. ([Source](https://x.com/pbteja1998/status/1911723180445610149))

  * Securing MCP servers is getting easier, with examples shared using [WorkOS AuthKit](https://x.com/WorkOS/status/1910722639036874943) and [Auth0](https://x.com/dschenkelman/status/1910693265566728319).

* **IDE Updates:**

  * JetBrains shared the public [WebStorm roadmap for March-April](https://youtrack.jetbrains.com/issue/WEB-72310). ([Source](https://x.com/WebStormIDE/status/1909291367504748937))

> **✨ Workshop Spotlight: Conquer the Complexity of Cursor (Europe Friendly Time!) ✨**
>
> Missed the last workshop or found the timing tricky? This one's for you! Master practical AI development workflows in Cursor in a session scheduled for **12:00 PM UTC** to better accommodate European attendees.
>
> This hands-on workshop covers Agents, Ask, Custom Modes, multi-file analysis, effective prompting, Cursor rules, and strategies for handling AI failures. Unlock Cursor's potential and streamline your development process.
>
> * **When:** \[Check website for upcoming dates - This session is Europe-friendly at 12:00 PM UTC\]
>
> * **Where:** Zoom (Live Q&A included)
>
> * **Investment:** $149
>
> ➡️ [**Read More about the Workshop**](https://egghead.io/workshop/cursor)
> ➡️ [**Register Now ($149)**](https://buy.stripe.com/7sI7tT81dfpC06s28c)
>
> *(Team training also available)*

## Community Buzz & Resources

* **MCP Explained:** Kent C. Dodds wrote a piece explaining [why he's excited about Model Context Protocol (MCP)](https://www.epicai.pro/the-game-changing-potential-of-model-context-protocol) and its potential. ([Source](https://x.com/kentcdodds/status/1911840456432034112))

* **Prompting Guide:** Ian Nuttall surfaced [v7 of Google's Prompt Engineering Guide](https://x.com/iannuttall/status/1911086164196606314), a deep dive into techniques and best practices. Definitely worth a look.

* **Discussion Starter:** Eric Zakariasson asked the community about their [favorite CLIs and MCP servers to use with the Cursor agent](https://x.com/ericzakariasson/status/1910808935961088346). What are you all using?

* **Gemini 2.5 Pro Praise:** The positive buzz around Gemini 2.5 Pro continues to grow in the community. It's getting rave reviews and even achieving 'S-tier' status on social platforms like Reddit for its coding capabilities. ([Source](https://x.com/suchenzang/status/1911251230317490416))

That’s a wrap for this week! There's always so much happening, it's hard to keep up, but hopefully, this helps surface some of the more interesting bits for developers working with AI.

If you have any feedback or questions, feel free to respond to this email. Always happy to talk shop about the latest AI tools.

John Lindquist

[egghead.io](https://egghead.io)

John Lindquist

AI Dev Essentials #2: GPT-4.1 Arrives, MCP Deep Dive & Google's Agent Dev Kit

AI Dev Essentials #2: GPT-4.1 & Gemini updates, MCP tools, Vercel v0, Google ADK, Cloudflare Containers news. Latest AI dev tooling highlights.

Hey Everyone 👋,

John Lindquist here. Since I've been diving deep into AI tooling and workflows over the past year, I'm starting this weekly newsletter to share updates on what interests me and could be helpful to the community. The goal is to help everyone stay up-to-date with the latest in essentials tools for AI devs.

I'll focus on relevant community news, model evaluations for coding, notable tools like Cursor and Windsurf, and practical workflows (including tools I build myself 😇). This week kicks off Cloudflare Developer Week with major announcements around agent/MCP services that many of us will likely use soon (I'll dig in and share my thoughts next issue). There are also lots of hints about new coding models possibly coming to Cursor (though my preference remains Gemini 2.5). Personally, I'm hoping for a Gemini Flash 2.5 variant. So let's hop into the latest! For my detailed, up-to-date workflows, check out the workshop info below.

Recent egghead.io lessons about AI tooling:

* **[Swarm Intelligence: Massively Parallelize Your AI Agents in Cursor](https://egghead.io/swarm-intelligence-massively-parallelize-your-ai-agents-in-cursor~g7u2g):** A workflow using `file-forge`, AI scripting, and a custom `git worktree` tool (`wt`) to launch parallel Cursor agents on different branches.
* **[Build a Better Edit Tool in Cursor with Custom Agent Modes](https://egghead.io/build-a-better-edit-tool-in-cursor-with-custom-agent-modes~21rr0):** Create a focused 'edit mode' in Cursor for precise AI refactors without conversational overhead, overcoming Command-K limitations.
* **[Visually Clone Websites with Gemini 2.5 Canvas for Cursor](https://egghead.io/visually-clone-websites-with-gemini-2-5-canvas-for-cursor~s5ugk):** Use Gemini 2.5 Pro's Canvas feature within Cursor to analyze and replicate website structures.

---

## Cloudflare Developer Week: Agent & Platform Updates

Cloudflare announced several updates relevant to AI application development:

* **Durable Objects Free Tier:** Lowers the barrier for experimenting with stateful serverless and the Agents SDK. ([Rita Kozlov](https://x.com/ritakozlov_/status/1909231625855983939))
* **MCP Enhancements:** BYO Auth (incl. [Auth0](https://x.com/auth0/status/1909307220816228354)) and Hibernation for MCP servers aim to improve agent security and efficiency. Exercise caution with MCP, but these are steps toward production viability.
* **Workflows GA & autoRAG:** Orchestration tool is now GA; a new autoRAG product indicates more integrated AI solutions.
* **Outerbase Acquisition:** Expect Durable Objects usability improvements following this acquisition. ([Rita Kozlov](https://x.com/ritakozlov_/status/1909232149246492887))
* **OpenNext Adapter Beta:** v1.0-beta for deploying Next.js apps on Cloudflare Pages adds caching, PPR, middleware support. ([CloudflareDev](https://x.com/CloudflareDev/status/1909598450871652398))

**Summary:** Cloudflare is actively enhancing its platform for AI/agent development, particularly reducing friction with Durable Objects and MCP.

## Llama 4 & Nemotron-Ultra Released

Meta's Llama 4 models began rolling out, with initial reports of variable quality across implementations. Meta attributes this to implementation stabilization, denying training on test sets ([Ahmad Al-Dahle](https://x.com/Ahmad_Al_Dahle/status/1909302532306092107)). Nvidia subsequently released **Llama-Nemotron-Ultra** (253B parameters), derived from Llama-405B via pruning and reasoning-focused post-training. Open weights and data are available ([Oleksii Kuchaiev](https://x.com/kuchaev/status/1909444566379573646)).

**Summary:** More powerful open models are available. Llama 4's initial rollout highlights the importance of stable implementations. Nemotron-Ultra adds a high-end specialized option.

---

## Quasar Alpha: Stealth Model on OpenRouter

OpenRouter provides early access to "Quasar Alpha," a model with limited public details but notable claims: 1M token context, benchmarks reportedly surpassing Claude 3.7 Sonnet, and >4x faster speeds. Reports suggest strong coding performance comparable to O3 Mini/DeepSeek R1 but significantly faster ([Matthew Berman's Thread](https://x.com/TheMattBerman/status/1908286423976886371)). The originating lab remains anonymous; speculation includes GPT-5, Claude 4, or Gemini 3.

**Summary:** The combination of large context, speed, and reported coding strength warrants attention for agentic workflows and large codebase analysis, despite benchmark caveats. Worth testing via OpenRouter if accessible.

---

**✨ Workshop Spotlight: Conquer the Complexity of Cursor ✨**

Master practical AI development workflows in Cursor. This hands-on workshop covers Agents, Ask, Custom Modes, multi-file analysis, effective prompting, Cursor rules, and strategies for handling AI failures.

* **When:** **This Thursday!** April 10, 2025, 9:00 AM - 2:00 PM (PDT)
* **Where:** Zoom (Live Q&A included)
* **Investment:** $149

Unlock Cursor's potential and streamline your development process.

➡️ [**Read More about the Workshop**](https://egghead.io/workshop/cursor)
➡️ [**Register Now ($149)**](https://buy.stripe.com/dR67tT4P17Xa8CYfZ1)

*(Team training also available)*

---

## Quick Links

* **Nightwhisper Buzz:** Highly-rated coding model "Nightwhisper" (rumored Gemini 2.5 variant?) left LMSys Arena; release may be imminent. ([ʟᴇɢɪᴛ Tweet](https://x.com/legit_api/status/1908264443827351913), [AiBattle Tweet](https://x.com/AiBattle_/status/1907519430961025476))
* **AI SDK Speech-to-Text:** Vercel AI SDK added a `transcribe` function. ([AI SDK Tweet](https://x.com/aisdk/status/1909603418639155460))
* **Gemini 2.5 Pro Updates:** Supports YouTube URLs as input in AI Studio (transcribe, summarize, analyze); reported improvements reducing stop issues/displaying thinking tokens. ([Jean Gatt Tweet](https://x.com/jean__gatt/status/1909256747518226829), [Eric Zakariasson Tweet](https://x.com/ericzakariasson/status/1908619515023548880))
* **Baby Cursor Project:** Cursor's Ryo Lu is building a rapid prototyping environment for IDE ideas. ([Ryo Lu Tweet](https://x.com/ryolu_/status/1908328050154233863))
* **(Rumor) Qwen3 Soon?:** Hints suggest Alibaba's Qwen3 model release is near. ([Elaina Tweet](https://x.com/Elaina43114880/status/1909572798944841859))

---

If you have any feedback or any questions, feel free to respond to this email. Always happy to talk shop about the latest AI tools.

John Lindquist

[egghead.io](https://egghead.io)

AI Dev Essentials #1: Cloudflare agent updates, Llama 4/Nemotron/Quasar models, Cursor workshop

Mock Service Worker is an API mocking library that allows you to write client-agnostic mocks and reuse them across any frameworks, tools, and environments.



Mocking WebSocket APIs with Mock Service Worker

**Note:** This course is being actively developed and more lessons will be added in the future.

Cursor is an AI-enhnaced code editor that allows you to call upon the robots to refactor or stub out functions for you with natural language. 

In this course, John will show you workflows that will save you time and effort by utilizing the features such as its mult-line editing and context.

In particular, by giving Cursor's AI the proper context, whether that's lines of code or multiple files, you'll get better output when trying to extend or refactor logic that's present.


Bite-size video tutorials for badass web developers.

egghead

Productive Developer Workflows with AI Enhanced Cursor IDE

Cloudflare secures and ensures the reliability of your external-facing resources such as websites, APIs, and applications. It protects your internal resources such as behind-the-firewall applications, teams, and devices. And it is your platform for developing globally-scalable applications.

cloudflare

Supabase Function Hooks allow us to subscribe to change events in the database - such as `insert`, `update` and `delete` - and make a HTTP request with the changed data.

In this lesson, we refactor our `revalidate` route to handle inserts, updates and deletes.

Additionally, we create a Function Hook to subscribe to all change events on the `articles` table, and automatically send a POST request to the `revalidate` route of our Cloudflare Worker.

This automatically refreshes the KV store anytime a value is changed in the database, and decouples the revalidation of our cache, from our user requesting data. This means, theoretically, users should never have to wait for a request to the Supabase origin server, as the cache is automatically populated, updated and cleared to remain in sync with the database.

## Code Snippets

**Update Revalidate route to handle insert, update and delete**

```javascript
router.post(
  "/revalidate",
  withContent,
  async (request, { SUPABASE_URL, SUPABASE_ANON_KEY, ARTICLES }) => {
    const { type, record, old_record } = request.content;
    const supabase = createClient(SUPABASE_URL, SUPABASE_ANON_KEY);

    if (type === "INSERT" || type === "UPDATE") {
      await writeTo(ARTICLES, `/articles/${record.id}`, record);
    }

    if (type === "DELETE") {
      await ARTICLES.delete(`/articles/${old_record.id}`);
    }

    const { data: articles } = await supabase.from("articles").select("*");
    await writeTo(ARTICLES, "/articles", articles);

    return json({ received: true });
  }
);
```

**Run wrangler development server**

```bash
npx wrangler dev
```

**Publish Cloudflare Worker with Wrangler CLI**

```bash
npx wrangler publish
```

## Resources

- [Supabase Functions blog](https://supabase.com/blog/2021/07/30/supabase-functions-updates#function-hooks-alpha)
- [Supabase.js docs](https://github.com/supabase/supabase-js)
- [Wrangler CLI docs](https://developers.cloudflare.com/workers/wrangler/commands/)
- [KV Storage docs](https://developers.cloudflare.com/workers/runtime-apis/kv/)

Automatically revalidate KV Store cache on change with Database Webhooks in Supabase

Cache Busting or Invalidation, is the process of clearing stale data from a cache. After the first request, the response data from Supabase is cached in our KV store, and never fetched again. This means if data in the database changes, our KV store will never be updated.

In this lesson, we create a `revalidate` route, which fetches fresh data from Supabase and updates the cache.

## Code Snippets

**Revalidate cache for articles route**

```javascript
router.get(
  "/revalidate",
  async (request, { SUPABASE_URL, SUPABASE_ANON_KEY, ARTICLES }) => {
    const supabase = createClient(SUPABASE_URL, SUPABASE_ANON_KEY);
    const { data: articles } = await supabase.from("articles").select("*");
    await writeTo(ARTICLES, "/articles", articles);
    return json({ received: true });
  }
);
```

**Run wrangler development server**

```bash
npx wrangler dev
```

## Resources

- [Supabase.js docs](https://github.com/supabase/supabase-js)
- [Wrangler CLI docs](https://developers.cloudflare.com/workers/wrangler/commands/)
- [KV Storage docs](https://developers.cloudflare.com/workers/runtime-apis/kv/)

Cache-busting with Cloudflare KV stores and Supabase

KV Storage is a read-optimized, eventually consistent cache that can be accessed from Cloudflare Workers. The interface for reading and writing is similar to `localStorage` in the browser.

In this lesson, we create a `read-kv` route for reading from the KV store. This automatically gets passed any KV stores that have been bound to the Cloudflare Worker. Initially, the store is empty, so returns the value `null`.

Additionally, we create a `write-kv` route to populate the store with test data.

To reduce the overhead of stringifying and parsing JSON objects, we create two helper functions to easily read and write values to any KV store.

Lastly, we publish a production version of our Cloudflare Worker, to confirm that writing these value locally - to our preview store - does not affect our production store.

## Code Snippets

**readFrom helper function**

```javascript
export const readFrom = async (cache, path) => {
  const data = await cache.get(path);
  return JSON.parse(data);
};
```

**writeTo helper function**

```javascript
export const writeTo = async (cache, path, data) => {
  await cache.put(path, JSON.stringify(data));
};
```

**Read KV route**

```javascript
router.get("/read-kv", async (request, { ARTICLES }) => {
  const articles = await readFrom(ARTICLES, "/articles");
  return json(articles);
});
```

**Write KV route**

```javascript
router.get("/write-kv", async (request, { ARTICLES }) => {
  const articles = [{ title: "test3" }, { title: "test4" }];
  await writeTo(ARTICLES, "/articles", articles);

  return json(articles);
});
```

**Publish Cloudflare Worker**

```bash
npx wrangler publish
```

**Run wrangler development server**

```bash
npx wrangler dev
```

## Resources

- [Wrangler CLI docs](https://developers.cloudflare.com/workers/wrangler/commands/)
- [KV Storage docs](https://developers.cloudflare.com/workers/runtime-apis/kv/)

Read and write KV Storage cache from Cloudflare Worker

Supabase is an open source Firebase alternative. A service to:

- Listen to database changes.
- Query your tables, including filtering, pagination, and deeply nested relationships (like GraphQL).
- Create, update, and delete rows.
- Manage your users and their permissions.
- Interact with your database using a simple UI.

Supabase is not a 1-to-1 mapping of Firebase. Most notably, Supabase uses Postgres rather than a NoSQL store. 

supabase

Itty Router is a tiny router package that has a similar API to Express. In this video, we install Itty Router and the Extras packages.

Additionally, we refactor our existing worker to use the router, and declare a dynamic route to fetch a single article.

To handle paths and articles that don't exist, we add a catch all route that returns a 404 status.

Lastly, we use the `json` helper to automatically stringify JSON objects and set the `Content-Type` header for `application/json`.

## Code Snippets

**Install Itty Router and extras**

```bash
npm i itty-router itty-router-extras
```

**Run wrangler development server**

```bash
npx wrangler dev
```

**GET route for all articles**

```javascript
router.get(
  "/articles",
  async (request, { SUPABASE_URL, SUPABASE_ANON_KEY }) => {
    const supabase = createClient(SUPABASE_URL, SUPABASE_ANON_KEY);

    const { data } = await supabase.from("articles").select("*");
    return json(data);
  }
);
```

**GET route for one article**

```javascript
router.get(
  "/articles/:id",
  async (request, { SUPABASE_URL, SUPABASE_ANON_KEY }) => {
    const supabase = createClient(SUPABASE_URL, SUPABASE_ANON_KEY);
    const { id } = request.params;

    const { data } = await supabase
      .from("articles")
      .select("*")
      .match({ id })
      .single();

    if (!data) {
      return status(404, "Not found");
    }

    return json(data);
  }
);
```

**Catch all route for 404**

```javascript
router.all("*", () => status(404, "Not found"));
```

## Resources

- [Itty Router repo](https://github.com/kwhitley/itty-router)
- [Itty Router Extras repo](https://github.com/kwhitley/itty-router-extras)

Proxy Supabase requests with Cloudflare Workers and Itty Router

Supabase JS is an NPM package which provides a simple interface from JavaScript to our Supabase project. It allows us to query and mutate data using its Object Relational Mapping (ORM) syntax, and subscribe to realtime events.

In this video, we install the Supabase JS package and create a new client using our project's URL and Anon Key. These can be found in the Supabase dashboard for our project, under `Settings > API`.

We store these values as secrets in our Cloudflare account, and use them to instantiate a new Supabase client.

Additionally, we write a query to select all of our articles from our Supabase instance, and send them back as the response from our Cloudflare Worker.

In order to send a JSON response, we first stringify the object we get back from Supabase, and then set a `Content-Type` header to notify the browser that this will be a type of `application/json`.

## Code Snippets

**Install Supabase JS**

```bash
npm i @supabase/supabase-js
```

**Create a Cloudflare secret**

```bash
npx wrangler secret put NAME
```

**Add a secret for SUPABASE_URL**

```bash
npx wrangler secret put SUPABASE_URL
```

**Run wrangler development server**

```bash
npx wrangler dev
```

**Add a secret for SUPABASE_ANON_KEY**

```bash
npx wrangler secret put SUPABASE_ANON_KEY
```

**Query data from Supabase**

```javascript
const { data } = await supabase.from("articles").select("*");
```

**Send JSON response**

```javascript
return new Response(JSON.stringify(data), {
  headers: {
    "Content-Type": "application/json",
  },
});
```

## Resources

- [Selecting data with Supabase JS](https://supabase.com/docs/reference/javascript/select)
- [Introducing Secrets and Environment Variables to Cloudflare Workers](https://blog.cloudflare.com/workers-secrets-environment/)
- [Cloudflare docs for sending JSON responses](https://developers.cloudflare.com/workers/examples/return-json/)

Query Supabase from Cloudflare Worker

Cloudflare Workers are serverless functions that run at the Edge! 🔪

The Wrangler CLI is a tool for interfacing with your Cloudflare account, and creating or publishing your Workers.

In this video, we use the Wrangler CLI to log in to our Cloudflare account and authorize the `wrangler` command to make changes on our behalf.

Additionally, we create a worker and host it locally with the `npx wrangler dev` command. We then demonstrate making a GET request to our Cloudflare Worker from the browser, and confirm it is sending the correct response.

By modifying the response locally, we can see that changes are reflected any time we refresh the browser.

## Code Snippets

**Login to Cloudflare with Wrangler CLI**

```bash
npx wrangler login
```

**Create Cloudflare Worker**

```bash
npx wrangler init supabase-at-the-edge
```

**Run wrangler development server**

```bash
npx wrangler dev
```

## Resources

- [Cloudflare Wrangler docs](https://developers.cloudflare.com/workers/wrangler/get-started/)

Create a Cloudflare Worker with the Wrangler CLI

We've seen how to return easy and a little complex data from our KV, but how about in a real-world application? We are going to remove the code we have created and set up a simple HTML application that will return our data based on an API which we will create. 

Update Cloudflare Workers KVs Data from an API Route

Behind the scenes, I've updated the HTML UI and added in some helper JS functions to allow us to render new to-do's. We are going to start off by adding in the UI for a user to be able to input their own to-dos. Then we are going to work on creating a backend to store that data and retrieve it using our KV key of `"data"`. 

Filter Data with Cloudflare Workers KV Keys

Fast, easy and reliable testing for anything that runs in a browser.

cypress

[Storybook](https://storybook.js.org/) is already powerful for being able to develop components in isolation as well as using those stories as living documentation for others. [Nx](https://nx.dev) goes a step further. It leverages the fact that Storybook exposes an `iframe.html` that allows to access the rendering of the story without the actual Storybook frame. On top of that, Nx generates a Cypress configuration to run tests against the Storybook stories.

Prefer to read along as well? Here's the [accompanying article](https://blog.nrwl.io/use-cypress-with-next-js-and-nx-to-battle-test-your-react-components-da273f664f81).


Write Cypress Tests for our React Storybook Components with Nx

React is one of the web’s most popular frameworks for building JavaScript applications. 

If you know what you’re doing, React can drastically simplify how you build, use, and maintain code.

Whether you’re a React newbie or you’re ready for advanced techniques, you can level-up with egghead. Explore our in-depth courses, lessons, and community resources to build more powerful applications and crack open your career.

react

In this lesson, we develop a new React component in an [Nx](https://nx.dev) library with Storybook. We explore how to leverage [Storybook](https://storybook.js.org/) to develop the component in isolation, how to expose the component props s.t. we can then dynamically change them in the Storybook rendering and much more.

Prefer to read along as well? Here's the [accompanying article](https://blog.nrwl.io/use-storybook-with-tailwind-in-an-nx-workspace-5ceb08edad71).

Develop React Components in Isolation with Storybook and Nx

Next.js is a minimalistic framework for server-rendered React applications.

Developing UI components is sometimes a highly visual effort. We continuously want to have feedback on how a particular change affects our component rendering and adjust accordingly. Most often, as a developer, we include these components in their target applications, just to get that visual feedback. This is far from ideal though.

[Storybook](https://storybook.js.org/) solves exactly this! It allows you to develop components in isolation and experiment with the inputs and outputs of a component. Furthermore, once the Storybook story is fully developed, it can serve as documentation for other developers to explore.

Prefer to read along as well? Here's the [accompanying article](https://blog.nrwl.io/use-storybook-with-tailwind-in-an-nx-workspace-5ceb08edad71).

Configure Storybook for your React Based Nx Workspace Library

Building a component library is a great way to gain efficiencies in creating accessible React apps and Storybook is a great tool for doing that. Using the accessibility add-on to Storybook you can test your components in isolation for accessibility issues before composing them into an application.

If you can write and test each of these components initially with accessibility in mind then you now have:

* A library of reusable components with accessibility baked in.
* You won’t need to solve the same problems over and over again.

## Resources
* https://storybook.js.org/
* https://www.npmjs.com/package/@storybook/addon-a11y

Audit Component Accessibility Using Storybook

Our application works but there is one major flaw. Everyone sees the same to-do's. To make to-do's user-specific, we are going to link users' data to their IP addresses so people only see to-dos based on their IP address. 

Identify Users in a Cloudflare Worker by IP to Serve User-specific Data

Now that we have our Workers project up and running, we need to create a KV namespace. A KV namespace is a key-value database that is replicated to Cloudflare's edge. Using the terminal, we will create our namespace and add it to our wrangler.toml file. 

Create a Cloudflare Workers KV Namespace

Creating a new workers project using Wrangler is pretty easy. We first will install and double-check that we have Wrangler installed. Then we will connect Wrangler to our cloudflare project. Lastly, using the terminal, we can easily create our new Wrangler project. 

Create a New Cloudflare Workers Project with Wrangler

We can store and retrieve our data from our KV but not the status of whether or not it's checked off. To do that, we create a function called `completeTodo` that will target the checkbox, find the todo based on its id, flips the boolean from false to true and saves that data, and then updates our to-dos. 

Edit Stored Data using the Cloudflare KV Key

We've learned how to write and receive data from our database, but we've only done it with fairly simple values. Now we are going to see how to do the same thing but with complex key values. There are two ways of doing this. One is the default route where we just return the value back from our KV. The second is where one route takes in a name parameter and sets it as the value for a key. The second path is the one we are going to look at in this lesson. 

Set Complex Key Values in a Cloudflare Workers KV Namespace

[Scraped MCP Examples](https://gist.github.com/johnlindquist/b19673bbf6a396406dff869beecace1d)
[ghx tool](https://www.npmjs.com/package/@johnlindquist/ghx)

Building complex components like Model Context Protocol (MCP) servers from scratch can be challenging, especially without good reference implementations. This lesson demonstrates a powerful workflow combining the `ghx` CLI tool with AI assistants (like Google's AI Studio and Cursor's agent) to overcome this hurdle.

You'll learn how to:

1.  **Use `ghx`:** Leverage the `ghx` command-line tool (which wraps the GitHub CLI) to search GitHub for real-world code examples based on specific import paths (e.g., `modelcontextprotocol/sdk/server/mcp.js`).
2.  **Refine Search Results:** Use `ghx` options (`--help`, `--limit`, `--max-filename`, `NOT demo`) within Cursor's chat to filter results, exclude simple demos, and gather a rich set of relevant MCP server implementations.
3.  **Provide AI Context:** Copy the aggregated code examples found by `ghx` into an AI environment like Google AI Studio (or ChatGPT).
4.  **Handle Context Limits:** See techniques for trimming large context files (like using Cursor's `Cmd+K` inline edit with `head -n` commands) to fit within model limits while retaining valuable examples.
5.  **Generate Code:** Prompt the AI (Gemini 2.5 Pro in AI Studio or ChatGPT O3) to generate a *new* MCP server (e.g., with five distinct tools) based *solely* on the provided real-world examples.
6.  **Integrate and Debug:** Set up the generated TypeScript code (`mcp_server.ts`) locally in Cursor, install dependencies (`pnpm install`), and use Cursor's agent (`Cmd+I`) or inline fixes (`Cmd+K`) to resolve TypeScript errors and path issues.
7.  **Configure in Cursor:** Add the newly created MCP server (running via `bun mcp_server.ts`) to Cursor's MCP settings, using the absolute path and the `bun` command.
8.  **Test the MCP Server:** Interact with Cursor's chat agent to call the custom tools (e.g., `add_note`, `list_notes`, `write_managed_file`) defined in the AI-generated MCP server, verifying its functionality.

This lesson showcases how combining targeted code searching (`ghx`) with the generative power of AI, fueled by relevant examples, can dramatically accelerate the process of building and bootstrapping complex tools and applications.

Generate and Debug MCP Servers from Scratch

In this quick walkthrough, you’ll learn how to drop Nx into an existing npm or pnpm workspace and immediately benefit from project graph visualization, caching, and smart task orchestration, all without rewriting your setup.

You’ll start with a standard React monorepo containing a Vite app, a UI package, and utility functions. Then, using a single command (`nx init`), you’ll initialize Nx and see how it auto-detects your existing scripts, builds a dependency graph, and enables advanced features like affected commands and local caching.

We're also going to explore optional enhancements using Nx plugins for Vite and React. You’ll see how they help Nx infer tasks directly from your Vite config files, improve DX with the Nx Console VS Code extension, and leverage Nx plugin generators to scaffold code with a consistent structure.

What you’ll learn
- How to initialize Nx in an existing npm or pnpm monorepo
- How Nx understands your workspace structure and scripts
- How local caching and affected builds speed up development
- How optional Nx plugins improve DX without adding bloat
- How to scaffold new packages

Using Nx on an existing React and NPM workspace based monorepo

Applying Nx to an existing React monorepo to enable caching, task orchestration, and project graph analysis without changing your current setup.

Typing repetitive or complex instructions for Cursor's AI agent can slow down your workflow. This lesson teaches you how to create custom slash commands (e.g., `/s term`, `/l`, `/c`) using Cursor's "Rules" feature. Learn how to map these simple shortcuts to specific AI actions, instructing the agent to use precise tools like `codebase_search`, `edit_file`, or `run_terminal_cmd` based on your command and the current conversation context.

**Workflow demonstrated in this lesson:**

*   List available AI tools (built-in and MCP) to get their exact names.
*   Navigate to Cursor Settings -> Rules.
*   Define custom rules under a heading (e.g., `## Slash Commands`).
*   Create rules mapping a slash command pattern (like `/s <term>`) to a detailed instruction specifying which tool to use and how (e.g., "Use the codebase_search tool to search for <term/>").
*   Define rules that leverage conversation context (e.g., for summarizing notes or creating commit messages).
*   Save the rules (potentially in `.cursor/rules/project.mdc` for team sharing).
*   Invoke the custom slash commands (e.g., `/s handle`, `/l`, `/c`) in the chat/agent window.
*   Observe the AI understanding the shortcut and executing the intended tool call.

**Key benefits:**

*   Creates efficient, reusable shortcuts for common AI interactions.
*   Reduces the need for typing lengthy, detailed prompts repeatedly.
*   Allows mapping simple commands to specific Cursor tool invocations.
*   Enables commands that leverage the ongoing conversation context.
*   Improves workflow speed and consistency when working with the AI agent.

Speed Up Your Agents with Cursor Slash Commands

Cursor's AI Agent has the abilitly to invoke MCP tools, but they lack direct access to your project. This lesson shows how to build custom MCP (Model Context Protocol) server tools that bridge this gap. Learn to define tool parameters using Zod schemas and the crucial `.describe()` method to explicitly request necessary context from the Cursor environment *before* your tool runs. See how the AI gathers this information (like Git status or version via terminal commands, or web search results) and passes it to your tool, enabling powerful, context-aware automation.

**Workflow demonstrated in this lesson:**

*   Scaffold a basic MCP server using a Cloudflare template (`pnpm create cloudflare`).
*   Run the MCP server locally and configure it in Cursor settings.
*   Define MCP tools (e.g., `status`) within the server code (`index.ts`).
*   Specify required context for tools using Zod schema parameters and `.describe()` (e.g., requesting "The status of the git repository").
*   Interact with the Cursor Agent using natural language (e.g., "Please check the status").
*   Observe the Agent's thought process: identifying the need for specific context based on the `.describe()` text.
*   See the Agent automatically using its *own* tools (like `run_terminal_cmd` or `web_search`) to gather the requested context *before* calling your MCP tool.
*   Watch the Agent call your MCP tool, passing the gathered local context (Git status, version, etc.) as arguments.
*   Receive the final response from the Agent, incorporating the information provided by your local MCP tool.

**Key benefits:**

*   Allows Cursor's AI to access and reason about information from your local machine (Git status, versions, file contents, etc.).
*   Enables the creation of AI tools that directly interact with or report on your local development environment.
*   Demonstrates the power of using `.describe()` in Zod schemas to guide the AI in gathering necessary context automatically.
*   Unlocks advanced automation possibilities by combining AI reasoning with local machine access.

Create a Custom MCP that Calls Cursor Tools

Vimium's Vomnibar is a "command palette"-like search tool for your open tabs, browser history, and bookmarks. We can search through and jump to any tab open across browser windows. We can also do a generalized search with results that also include browser history and bookmarks which can either be opened in the current tab or a new tab. If you're anything like me, you open tons of tabs and visit hundreds of webpages over the course of a week. The vomnibar puts all of that at your fingertips.

Josh Branchaud

Open Tabs, Browser History, and Bookmarks with the Vomnibar

Vimium's Vomnibar is a "command palette"-like search tool for your open tabs, browser history, and bookmarks.

Another aspect of Vimium's configurability is customizable key mappings. We can add new mappings and override existing ones. If there is a certain Vimium feature you want to make easier to trigger, adjust the key mapping to suit your needs.

Configure Custom Vimium Key Mappings

Another aspect of Vimium's configurability is customizable key mappings. We can add new mappings and override existing ones.

Many aspects of Vimium can be configured in order to bend the tool to your specific needs and use cases. We look at how to configure what sites turn off Vimium, the default search engine, link hint characters, and other basic settings. We also see how both insert mode and searching a visual selection work. Custom keymappings and custom search engines are covered in subsequent lessons.

Configure Basic Aspects of Vimium

Many aspects of Vimium can be configured in order to bend the tool to your specific needs and use cases.

Vimium's "marks" feature lets you mark positions in the current tab and across tabs. These are positional markers that you can jump back to. For instance, as you browse a huge page of documentation or a massive forum discussion, you can leave a series of "dog ears" to sections or conversations that you'll later want to revisit. Each tab supports its own set of lower-case letter marks. Upper-case letter marks are shared across tabs allowing you to seamlessly move between a specific set of tabs regardless of how they are arranged.

Set Marks on a Vimium Webpage You Want to Jump Back To

Vimium's "marks" feature lets you mark positions in the current tab and across tabs. These are positional markers that you can jump back to.