Build your own Developer Tools with Claude Code

I break this down into a 3 step process:

1. Build the app

2. Wrap it in a CLI

3. Give your agent a Skill

This is a reusable framework that will allow you to build custom developer tools that integrate natively with your coding agents.

This isn’t just a demo for YouTube—I’ve been using this workflow myself in my work as an AI Engineer and I LOVE it.

Watch the video on YouTube

In this video I'll show you a full walkthrough of building a developer tool from scratch with Opus 4.7.

This video is sponsored by Anthropic.

Get started with Claude Code on the Max plan:
https://clau.de/ZazenCodes

Topics from this week’s video

• Build custom developer tooling with Claude Code

  • Demo a Kanban board build

  • Walk from app creation to reusable agent tooling

• Create the Kanban workflow

  • Build a web UI, add an API-backed CLI, then wrap it as a Claude skill

  • Use context files to document and operationalize the workflow

• Build the web app

  • Scope requirements with brainstorming and voice mode

  • Build and iterate on a React/Express app with dark mode and multi-project support

• Add the CLI

  • Create terminal commands for projects and cards

  • Link the CLI globally so Claude can update the board directly

• Create a reusable Claude skill

  • Teach Claude how to use the CLI

  • Move the skill to user scope so it works across repositories

• Improve reliability through context

  • Add CLAUDE md and repo instructions to reduce mistakes

  • Let Claude create relevant tasks for active projects

• Keep everything synchronized

  • Add guidance so app, API, CLI, and skill evolve together

  • Use hooks to update skills and local tooling automatically

• Takeaway

  • Treat custom tooling as a practical layer of personal developer workflow

  • Use Claude Code to plan, build, test, and maintain it

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Write programs that do one thing and do it well.

Ken Thompson