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Knowledge / AI Starter

Knowledge · AI Starter · free

From Chat to Your Own Tool

How to build your first tool of your own with an AI agent over a weekend. You don't need to know how to program, and you'll end up with something you can trust. Here's the whole path in seven steps, plus a detailed guide to download.

Get the free guide See the seven steps

As of September 29, 2026 · Created with AI assistance, facts checked against the original sources.

What just changed

Stop copying code. Let the agent build.

A chat window answers with code that you copy back and forth yourself. A coding agent like Claude Code or Codex works right inside a folder on your computer: it creates files, runs them, sees the errors and fixes them. You say what you need and check the result. That division of labor is what you'll learn here.

At a glance

How to get started, in seven steps

  1. Understand

    A chat answers with code you copy around. A coding agent works in a folder on your computer, runs what it writes and checks it. You say what you need and decide whether the result is right.

  2. Choose

    Our pick as of September 2026: Claude Code with Claude Opus 5.5 on the Pro plan, $20 a month plus applicable tax, billed monthly so you can cancel. If you already pay for ChatGPT Plus, use Codex with GPT-6 Sol.

  3. Set up

    Download the Claude desktop app for Mac or Windows, sign in, open the Code tab and pick a project folder. No terminal needed. Plan on half an hour.

  4. Build

    Start small: one input, one output, one check. Describe the goal and the limits, let the agent ask questions, ask for a plan and for tests, try the result yourself, set a save point.

  5. Repair

    When something turns red: describe the symptom, ask for a test that shows the bug, then let the agent fix it. After two failed fixes, start a fresh session instead of typing the tenth correction.

  6. Remember

    Run /init to have Claude write a CLAUDE.md, then add what it can't know on its own: your rules, what's off limits, how to test. From then on, every new session knows what the project is about.

  7. Stay safe

    No passwords in the project, real data only at the very end, and Plan mode before big changes. Then by Sunday evening you have a tool you can trust.

The guide walks through every step with the exact wording of each request and pictures of the Claude app, and it tells you what to do when you get stuck.

From Chapter 4 of the guide: your first request, in Plan mode

Recreated view · Claude desktop app for macOS, as of September 2026

Tell Claude

I want a simple expense log that runs only in the browser, with no server and no sign-in. I want to enter expenses (date, amount, category, note), see totals per month and per category, and export everything as a CSV file for Excel. My data should never leave my computer. Ask me questions before you build anything.

What you should see

  • A list of questions, usually with a suggested answer for each.
  • Keep your answers short. “Go with your suggestion” is a perfectly good answer.

Three videos

Three moves, shown instead of described.

Three short films that walk you through one move at a time. They work without sound.

  1. From an empty folder to your first tool About 77 seconds. Create a folder, start Claude, give your request, read the plan, get the tests to green, try it in the browser, set a save point. Recreated view of the Claude app, as of September 2026. Created with AI assistance.
    Film transcript
    1. Video 1 of 3 · AI Starter · From an empty folder to your first tool · With the Claude app, step by step.
    2. Choose your project folder · Recreated view · Code › New session › Local › Select folder
    3. Set the mode to Plan · Recreated view · Plan mode: Claude reads and plans, edits nothing.
    4. Describe the goal and the limits · Recreated view · Copy the exact wording from the guide, Chapter 4.
    5. Claude asks questions first · Recreated view · Keep answers short. “Go with your suggestion” works.
    6. Read the plan, then accept it · Recreated view · Then set the mode back to Manual.
    7. Let it build, with checks · Recreated view · Your number will differ. What matters: fail 0.
    8. Try it in the Browser pane · Recreated view · Or double-click the HTML file in Finder.
    9. Make a save point · Recreated view · In Manual mode, Claude asks before every change.
    10. The whole path, step by step: in the free guide. · Recreated view · Made with AI assistance
  2. Project memory in one minute About 65 seconds. What goes into a CLAUDE.md, and how one AGENTS.md serves Claude Code and Codex at the same time. Recreated view of the Claude app, as of September 2026. Created with AI assistance.
    Film transcript
    1. Video 2 of 3 · AI Starter · Project memory in one minute · CLAUDE.md and AGENTS.md, on a real example.
    2. A new session doesn't remember yesterday's conversation. · Anything it needs to know goes in a file.
    3. Have Claude write a first draft · Recreated view · Claude writes a CLAUDE.md for your project.
    4. Four blocks are enough · File AGENTS.md (excerpt): ## What it is / An expense log that runs entirely in the browser. … / ## Structure / - src/expenses.js — all the calculation logic. … / - src/app.js — interface only: … / ## Commands / - Tests: npm test … / ## Rules / 1. Amounts are always whole cents (integers). … / 4. Never send data anywhere. … · Block: What it is · Block: Structure · Block: Commands · Block: Rules · The rules are the most valuable part.
    5. One file for Claude Code and Codex · File CLAUDE.md (excerpt): @AGENTS.md / ## For Claude Code only / - For new features, use the /new-feature skill. … · Block: Imports AGENTS.md · Block: Claude only · How the tools read it: Codex reads AGENTS.md directly. / Claude Code reads it through the import.
    6. What goes in, and what stays out · Put in: Commands Claude can't guess / How testing works / What is explicitly forbidden · Leave out: What the code already shows / Platitudes like “write clean code” / Passwords, keys, personal data. Never. · The official target is under 200 lines.
    7. Same mistake twice? Add one line. · Tell Claude (in the prompt box): You've stored amounts as decimals twice now. Add a rule to CLAUDE.md that prevents this from now on, and show me the line you changed. · The rule behind it: Add a line when a mistake happens twice. / Not just in case.
    8. Chapter 6 and the sample project: in the free guide. · Recreated view · Made with AI assistance
  3. Keep working from your phone About 62 seconds. Turn on Remote Control, open the session in the Claude app on your phone, answer a question. Recreated view of the Claude app, as of September 2026. Created with AI assistance.
    Film transcript
    1. Video 3 of 3 · AI Starter · Keep working from your phone · Your Mac does the work, your phone steers.
    2. Turn on Remote Control · Recreated view · The first time, confirm with Enable Remote Control.
    3. On your iPhone: Claude app, then Code · Recreated view, schematic · Your Mac's sessions: computer icon, green dot.
    4. Answer requests from your phone · Recreated view, schematic · If you can't read it, don't approve it.
    5. Your Mac stays on, the Claude app open. · After sleep, it reconnects when your Mac wakes.
    6. Two routes to your phone · Remote Control: Your Mac does the work / Your phone steers / Modes: Manual, Accept edits, Plan · Cloud session: Runs without your Mac / Your project must be on GitHub / Modes: Accept edits, Plan, Auto · Both end up in the Claude app, under Code.
    7. What works well from your phone · Good from your phone: Check how far Claude has gotten / Answer questions / Give small, well-defined tasks · Better at your desk: Reviewing bigger changes / Publishing or uploading / Trying out the result yourself · Steer from your phone, approve at your desk.
    8. Both routes, step by step: in the free guide. · Recreated view · Made with AI assistance

What's in the guide

12 chapters over two weekends.

First weekend

  1. From chat to agent
  2. Tools, models, costs
  3. Setup: the first half hour
  4. Your first tool
  5. When it turns red
  6. Project memory
  7. Staying safe, keeping costs down

Second weekend

  1. Skills, subagents, hooks, workflows
  2. GitHub, the treasure chest
  3. Steering from your phone
  4. Side trip: Meta Muse and Grok
  5. Ten ideas and where to go next

The second weekend is optional. If you stop after Chapter 7, you'll have a working tool and everything you need to build the next one.

Plus an example project to download: my-expense-log, a working expense log with CLAUDE.md, AGENTS.md, two skills, two subagents and automated tests.

The guide as a PDF and the example project as a ZIP file. Free.

Request the guide

Get the free guide

Free. You get the guide right away – plus an occasional email about our own guides and tools. Unsubscribe anytime via the link in every email or at kontakt@dargel-solutions.de, at no cost other than transmission costs at basic rates.

Privacy

Questions

Short answers.

Do I need to know how to code?

No. You need a Mac or a Windows PC, the free Claude desktop app, a subscription, a weekend, and a little patience during setup. You won't need a terminal.

What does it cost?

The guide is free. The AI agent needs a subscription: Claude Pro costs $20 a month plus applicable tax (€18 plus VAT in the EU), ChatGPT Plus costs $20 a month. Local prices and tax depend on your billing address. To try it for free, use GitHub Copilot Free, the Gemini CLI, or Codex on the free ChatGPT plan.

Why do you recommend Claude Code?

We work with it every day, and we think it currently has the most complete toolbox for beginners: Plan mode, project memory, skills, subagents and steering from your phone, all on the cheapest paid plan. Chapter 2 of the guide gives the full reasoning.

Do you get paid for the recommendation?

Claude has a guest pass program, and the guide contains one labeled referral link, always with the direct link right next to it. ChatGPT has no comparable public program. We'd make the same recommendation without the link.

What happens to my email address?

You get the guide right away and, now and then, an email in English about our own guides and tools. No tracking in our emails, and we don't pass your address on to anyone for their marketing. Unsubscribe anytime with the link in every email.

Sources & notes

How this page was made.

Information as of September 29, 2026. Prices and features come from the providers' own pages, where we checked them on a stated date; providers change them without notice. Created with AI assistance and edited by us. Transparency notice under Article 50 of the EU AI Act. Claude, ChatGPT, Codex, Grok and Meta are trademarks of their owners. We have no connection to these companies other than the labeled referral link.