---
title: "An Opinionated Guide to Which AI to Use to Do Stuff"
source: "Simon Willison 博客（Atom）"
source_tier: "t2"
url: "https://simonwillison.net/2026/Jul/27/an-opinionated-guide-to-which-ai-to-use-to-do-stuff/#atom-everything"
permalink: "https://feed.astralor.com/items/itm_db1f5ea7924a0b6334c229fd"
published: "2026-07-27T21:55:53.000Z"
score: 80
channel: "ai"
tags: ["Anthropic","ChatGPT","Claude","Google","OpenAI","Agentic Systems"]
---

# An Opinionated Guide to Which AI to Use to Do Stuff

## AI commentary

> This blog post is Simon Willison's refined take on Ethan Mollick's guide, ideal for developers and power users struggling to choose between ChatGPT and Claude and their various agent modes. It cuts through the confusion of product naming and unintuitive platform differences, offering clarity that saves hours of trial and error.

## At a glance

Ethan Mollick's guide to using AI has shifted in the past year from focusing on chat models (ChatGPT, Claude, Gemini) to emphasizing agentic systems where AI can perform hours of human work in one go. Gemini has been dropped due to lacking a mature entry in the Codex/ChatGPT Work/Cowork category. The post explains ChatGPT's Work and Codex modes, Claude's Cowork and Code modes, and how giving AI access to your computer unlocks more capabilities, while noting the confusing differences between mobile Work mode and desktop Codex.

## Key points

- Core shift: from chat models to agentic systems where AI can autonomously complete hours of human work in one go.
- Gemini removed due to lack of a mature product in the Codex/ChatGPT Work/Cowork category.
- ChatGPT's agent modes: Work and Codex; Claude's: Cowork and Code; naming is confusing but capabilities differ.
- Granting AI access to your computer via desktop app is the most powerful approach; mobile Work mode differs significantly from desktop Codex.

## Full text

An opinionated guide to which AI to use to do stuff It's interesting watching the evolution of Ethan Mollick's guide over time. A year ago it was still all about chat - ChatGPT, Claude, Gemini - with o3, Claude 4 Opus, and Gemini 2.5 Pro as the models and Deep Research as a useful alternative mode. Today it's much more about agentic systems - "where the AI is capable of doing the equivalent of many hours of real human work in one go". Gemini has fallen off Ethan's list, since Google still doesn’t have an established entry in the Codex/ChatGPT Work/Cowork category. Gemini Spark has yet to prove itself! Ethan offers a useful explanation of the ways you can give ChatGPT or Claude a computer to use: To use the computers provided by the AI companies, the mode you want is called ChatGPT Work in ChatGPT, and Cowork in Claude (the naming will not get less confusing, I am sorry to say). [...] The most powerful way to use AI is to give it access to your computer. You do that by downloading the ChatGPT or Claude apps and picking a mode to use. ChatGPT's two agent modes are Work and Codex; Claude's are Cowork and Code. The names do not map onto each other in any way that will help you remember them. And yes, these use the same names as the Work and Cowork modes we discussed above, but operate differently, and have more features and capabilities because they can access your computer. I think the difference between ChatGPT Work on a mobile device and ChatGPT Work inside the desktop app (where it's effectively a less intimidating skin on top of Codex) is spectacularly unintuitive. Short version: if you flip ChatGPT mobile from "Chat" to "Work" mode you get a version where its Code Interpreter container is no longer restricted from accessing the internet! Tags: ai, generative-ai, llms, ethan-mollick, code-interpreter, general-agents

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