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The Liberation Engine

Things to make / Recipe 06 of 14 · Decide

Build a repair or replace calculator you can challenge

Change one cost and watch the comparison flip.

What the agent made

Ran it for real with Claude Code 2.1.292 and OMP 18.8.5 on 2026-10-08, in an empty session with no saved memory. Your result will differ.

Open what Claude Code made, full screen

The same prompt in OMP made its own version: open what OMP made. Two runs, two different results: that is normal.

Make your own

  1. Get the files

    Make an empty folder called cli-practice in Downloads. No downloads: start in an empty folder.

  2. Open your agent in that folder

    Open a terminal in cli-practice and type claude or omp --approval-mode always-ask. First time? Set up in about five minutes, with steps for Mac, Windows, and Linux.

  3. Paste this prompt

    Build self-contained calculator.html here using plain HTML, CSS, and JavaScript. Inputs: repair and replacement costs and lifespans. Show both formulas and live cost per year, highlight the lower annual cost without claiming it is the best decision, and reject zero or negative years. Clear outdated results for invalid inputs. Start at $60/2 years versus $200/5 years. Show a $100 repair example. Stay in this practice folder; do not install packages, access the network, or use external resources. Use commas, not em dashes.

    The prompt asks the agent to stay in this folder; it cannot enforce that. Read each file change and command before you approve it.

  4. Check it yourself

    Open cli-practice/calculator.html in your web browser (double-click it), then:

    Human check: Open calculator.html: $60/2 is $30/year versus $200/5 at $40/year. Change repair cost to $100 and verify $50/year and the comparison flips; set years to zero to see validation.

    When we checked the recording above: Opened calculator.html in Chromium. Default $60/2=$30/year versus $200/5=$40/year; changed repair to $100 and saw $50/year with replacement now lower. Zero years showed an error and cleared the repair result; no external resources.

Why an agent, not a chat window

The agent makes a working offline calculator with inspectable formulas rather than only describing the math.