Make your personal finance app work on your phone

A personal finance app only lived on the laptop; Codex mobile-optimised it so payments get logged on the go.

by Cecilia Kim4 Sep 2026

Prompt for your agent

Goal: Make my personal web app usable on my phone.
Setup: agents used in source: Codex.
Steps:
1. Ask Codex to mobile-optimise the site.
2. Use it on the go so you log entries where they happen.
Rules: ask me before anything irreversible (sending, posting, paying, deleting); don’t invent data, results or tools I haven’t given you; tell me what you couldn’t verify.
Based on: Cecilia Kim — https://x.com/ceciliakdesign/status/2095959197456257337 (summarised from source; the source has no explicit step list)

Steps are our summary of the source (it has no explicit step list). Includes a “Based on” credit line.

I tried this

Tell the next builder. One anonymous answer each; click again to undo.

Agents, models and tools only what the source states

Agents
Codex

Sources & credit