I’ve never assumed any one tool can do everything, and neither should you. These are like apples and oranges, so picking something like Claude over Gemini or Codex isn’t something I recommend. These AIs are trying to do the same thing, but they are done in very separate ways. You should be using those strengths to make your own apps better. I used them together to make a calculator in under 10 minutes, and it did exactly what I needed.
They are good AI to use
There’s nothing wrong with a specialized tool
When you sit down to build software with modern artificial intelligence systems, you will notice that these systems bring powerful capabilities when used on their own. Claude is a great tool for following complex instructions and staying on track during long conversations. This makes it helpful for brainstorming and planning at the start of a project.
It operates like an experienced technical lead who wants to understand the whole picture before writing any code. With its context window of one million tokens, Claude can ingest entire repositories, remember your design decisions from hours ago, and catch subtle logical inconsistencies that other models miss.
This sounds simple, but when your AI is built to only execute, it is harder for it to understand where things are going wrong or where it’s missing the user’s idea. Claude asks clarifying questions and talks about trade-offs instead of rushing into execution, which is something that helps it outside of coding. This deep reasoning makes it a good way to map out new features or audit a messy codebase for structural flaws without losing the core intent of your project.
I let Claude look through my projects to see if I’ve screwed up any code or if there’s something that could be better. In fact, I have a zoom feature on my image editor because Claude brought it up before I was even in a position to need it. I totally forgot that would be a necessity and wouldn’t have remembered until I was knee-deep in making images.
Codex works great because it writes functional code and handles logic better than most general models that try to do too much. Gemini has a habit of trying to do things that I never told it to do. It has to constantly be reminded that it is a machine, and I am always correct about the path forward. Codex doesn’t make those mistakes and is more focused on doing exactly what you want to do.
It doesn’t need configuring in the same way Claude does to get moving quickly. Instead, it relies on its specialized training to write syntax, scaffold new components, and resolve terminal errors at a very fast pace. The system gets straight to work without pausing to offer unsolicited advice or long explanations. It is so relieving when you’re tired of an AI asking if you’d like it to execute its own ideas instead of just writing out the small feature you need, and not the huge app it thinks you want.
Some things are better when you focus on their strengths
Big picture planning works hand-in-hand with technical execution
Claude’s specialty is to act like a project organizer who focuses on research and planning the overall layout of an application before any code is written. When you feed it a rough idea, it takes time to map out the entire project, figure out file dependencies, and draft a detailed design document.
It understands human intent very well and handles the messy parts of a project where requirements are vague or unclear. If you give it instructions with missing details, it typically stops to ask clarifying questions and lists out its assumptions before it moves forward. That’s what you want to start with. Instead of jumping straight into writing code, use Claude to build a structural foundation that guides the rest of the development process.
Its ability to read through multiple files at once gives it the massive context needed to spot long-range dependencies across your system. By letting you offload the heavy mental lift of system design, Claude frees you up to focus on the actual logic of your application.
Once that plan is ready, have Codex step in to do the programming. Codex doesn’t ask questions or brainstorm ideas. It takes the specific instructions mapped out by Claude and executes them directly inside its environment. Since the model already mapped everything out, you don’t actually need to worry; just go back to Claude if you need anything new, and it’ll help you word everything.
Since it sticks strictly to the rules of a programming language, it is very fast and precise at writing the actual logic needed to make the application run. Claude will even tell you when to break things down into pieces to make it easier for the other model to handle.
How I made a calculator using Claude and Codex
It was incredibly simple
When I want to make a whole app that is simple, I’d rather just leave it to an AI than do it myself. It doesn’t need a personal touch if it is a calculator. I asked Claude for help, and I questioned it when it wanted me to do a little more than I planned on doing.
Once the plan was set, I passed those instructions to Codex so it could focus on the coding with a level of precision that doesn’t usually happen when Claude works alone. I don’t have Python or py in Codex because I’d rather run it locally to see things. However, Codex runs in a sandboxed cloud environment and turns your abstract requirements into working code, so feel free to set it up how you’d like.
Codex took a little over 2 minutes per prompt, and I only gave it two, so it was very fast. Talking to Claude didn’t take very long either.
Then, I just went into the folder where the readme was and double-clicked the main file to open it. Be sure you have Python and any needed plugins before you do this. I use Python normally, so I didn’t have to install anything. I was done about ten minutes later, and it really was that easy.
I don’t recommend doing this with super complicated apps, since no AI, not even Antigravity, gets everything right. However, it is great for running simple apps that you don’t want to find, like screenshots, calculators, or even photo editors.
Two is better than one
The three biggest mistakes people make with AI are thinking it can do all the work for them, that it is great on its own and doesn’t need humans, and that one AI can do everything. AI is just a tool, and that can sometimes be fun, but it can lead to tragedy. Knowing the strengths and weaknesses of your tools will help you use them better. In this case, using two AIs can give you a brand new calculator app that replaces one that used to cost over $1,000 when I was in high school.

