JAEN

Independent studio — Tokyo

Build small, prove it, make it stick.

From untangling the problem to designing, building and running the tool — AI and cloud, delivered end to end by one engineer.

Start a conversation →

What I do

  1. 01

    Framing & design

    We put the problem into words together, and decide what to build — and what not to.

  2. 02

    Prototype to production

    A working prototype in days, refined into production through real use.

  3. 03

    Run & maintain

    Improvements, dependency updates and incident response after launch.

Selected works

Products

  1. 01resume99A free résumé builder made specifically for IT engineersCloudflare Workers · Google Login
  2. 02Slack Schedule PollA Slack app for scheduling events and checking who can attend, without leaving SlackSlack API · Cloudflare Workers · D1

In development

  1. 03Corporate BrainAn AI agent shared across a company that gives every employee their own secretary (Claude API)Cloudflare Workers · Claude API · Google Workspace
  2. 04Mem SecretaryA secretary for sales teams that remembers what you say (runs on AI inside Cloudflare)Workers AI · iOS · Android
  3. 05PM Context MCPAn MCP server that lets each company build up and reuse its knowledge of AI-driven developmentMCP · RAG · Cloudflare Workers
  4. 06Secret Context RAGA context RAG for building a copy of yourself — one per personRAG · MCP · Cloudflare

Tools

  1. 07Claude Code Git GraphA mod that shows your Git graph inside Claude CodeClaude Code · Mod
  2. 08Limit BarsA mod that shows your remaining Claude Code usage at a glanceClaude Code · Mod
  3. 09AI Usage BarA Mac app that shows your Claude and Codex usage at a glance in the menu barmacOS
  4. 10MenuBar CustomA Mac app for tidying up what appears in the menu barmacOS
  5. 11Voice to CaptionA very lightweight voice input app for MacmacOS · Voice input

About

I started my career as an infrastructure engineer and have spent around 16 years as a project manager. In 2015 I founded a software development company, ran it for about 11 years, and then stepped away from it. After a stint at a consulting firm, I now work as a freelancer.

I first realised how powerful AI had become in autumn 2023. By the end of that year I had asked everyone in the company to try it, and we started by testing together whether it was actually useful.

What I value most is acting first and trying things myself — and getting through problems together rather than alone. Let AI handle what it can, so people can focus on what only people can do. To get there, I build the systems that let teams use AI to the full, and help clear the path to adopting it.