Codex can get dumber and slower on long sessions. Here's the fix: 1. Run Process_narration=false This will stop Codex from showing you all the planning steps, resulting in saving a lot of output tokens. 2. Prompt: "Act as an orchestrator. Use parallel agents to do the research and execution work. Write detailed tasks for each parallel agent and force them to act, iterate, get their tasks done, and bring back an in-depth report. Your job is to deeply analyze the agents' work, provide feedback, and provide them with continuous tasks." This prompt offloads the majority of the context-burning work to agents, and each agent has its own context window. So you can utilize 5 agents (5 context windows). 3. Add this hard rule: "Measure twice, cut once policy." Debugging and patching is messy work. Force Codex to plan first, act after (don't use plan mode; it's just overcomplicated). Ask it to make a task list for every task so it can track progress and iterate better. 4. Add this hard rule: "Keep the codebase clean, no tmp files, no dead code, no dead files. Stay organized all the time. No unnecessary folders, subfolders, or files." Claude keeps most of its working files in cache as temporary files (which is bloatware, but it keeps the codebase neat), but Codex is output-heavy. It creates tons of folders and files, and your workspace can become a mess after a few sessions. As a result, this contaminates the context window and degrades performance. Force Codex to stay organized and follow the file structure. These 4 techniques can help you save 40% context every session, and performance will be a lot better. For planning, use Codex 5.5 (extra high), and after the plan is done, shift to Codex 5.5 (high) with fast mode. This works faster.

Codex 5.5 hack: "Are you 100% confident in this strategy? If not, find all possible loopholes, suggest proper fixes and run this loop until you are factually 100% confident in the new startegy" This works like charm. It makes Codex 5.5 high perform even better than codex 5.5 extra high. Why? Codex 5.5 is the only model i noticed that is self aware. It never makes high claims unless the model verifies everything. This doesn't work with Opus 4.7 cuz that's a very insecure model. You can paste this prompt over and over again, the model keeps saying "you're absolutely right,....." But with codex, after 2-3 iterations you'll notice yourself it actually patched all loopholes and this genuinely sounds like a good strategy. Try this out, thanks me later.