Essential Tools for Building Custom AI Agents

I've been dabbling in building custom agents over the last week.

While Cloudflare keeps being in the news for their part in recent internet outages (and providing solid recaps of what went down), I've been experimenting with their Agents SDK to spin up custom agents on thier platform.

You may ask: why even build a custom agent when OpenAI and others are rolling out agentic features directly on their platforms?

Custom agents give you more control, letting you target niche workflows, improve efficiency, and work with your personal data. Plus its just fun to experiment with new tech.

Let’s dive into the newest tech stack for building custom agents.

📰 Article
What even are Cloudflare Durable Objects?
Boris Tane
I had absolutely zero knowledge of Durable Objects before reading this article. Boris Tane does a great job explaining what they are, what they can do, and lays out a framework for implementing them effectively. Think of them as mini databases that can be spun up as needed to hold data for your serverless functionality.

🎥 Video
Cloudflare Agents 101 - Deploy your first AI agent
Dive right into building a custom agent on Cloudflare's platform. This quick 30-minute introduction explains the code behind Cloudflare's Agent Starter repo and covers key concepts to consider when building custom agents.

💻 Framework
AI SDK
If you're building a custom agent, chances are you'll want to integrate with a large language model (LLM). You can deal with individual model providers' technical documentation, or you can offload that work to the developers at Vercel who have put together a standard SDK for integrating models from selected partners, including the big hitters like OpenAI, Anthropic, Google, and more. It's a Vercel-backed project, but it isn't locked into Next.js or React—it can be used with Vue, Svelte, Node.js, and more.

📰 Article
Introducing AgentKit
OpenAI
If you want to build custom agentic workflows with less code and more of a node-based UI workflow, then OpenAI, n8n, Zapier, and Langflow have you covered. They provide a UI for creating workflows that can interact with various models to help you create your own custom agents.

💡 Pro-tip
Opus 4.5 Sees the Whole System
This video was a good breakdown of one developer's experience with Opus 4.5 (and Gemini 2.0 Flash Thinking) solving bugs that previous top-tier models spun out on. What really grabbed my interest, though, were the interactive bug reports and explainers he used Opus 4.5 to generate. Ask the agent to generate a report about the issue and steps taken to debug, then feed that to another agent to generate an interactive infographic explainer for the bug and resolution. I could also see this being a really useful tool for learning or exploring codebases.

Thans for reading,

Jason