A week running Claude Code, Codex, and Gemini CLI as coding agents on the same repo. Where each one actually breaks.

I have been running all three terminal coding agents against the same real project for about a week, giving them the same tasks so I could see how they actually differ once you are past the demos. Sharing what stood out, curious if others see the same. Claude Code held context across multi step tasks the best. When a change touched several files it kept track of what it had already done and did not wander. Where it broke for me was cost. If I let a session sprawl it burned through budget fast, and the fix was mostly discipline: fresh session per task, tight scope, a short context file at the repo root. Codex was the most literal. It did close to exactly what I described and rarely added surprises, which I liked for well specified changes. Where it broke was ambiguity. Give it a vague instruction and it would stall or do the smallest possible thing, so I had to be more precise up front than with the others. Gemini CLI won on raw context size. When a task needed it to reason over a lot of files at once it handled that better than the other two, and the free tier made it easy to just try things. Where it broke was consistency. The same prompt could give me a clean result one run and a confused one the next, more than I saw with the others. The thing that surprised me is how much the differences came down to the same few habits regardless of tool: keep a context file, work in small scoped steps, and make it show a plan before it edits. Those helped every one of them more than switching between them did. For those of you running these as agents, what breaks for you, and have you settled on one or do you switch depending on the task?