GPT95 vs Codex

"This Visual Studio Code extension allows you to use ChatGPT combined with our Fine-Tuned GPT3 Code Model to generate code or natural language responses to your questions.

Automatically generate code from scratch, ask questions, get explanations, refactor code, find bugs and more!"

Codex is OpenAI's agentic coding assistant that writes features, fixes bugs, answers codebase questions, and opens pull requests from ChatGPT, a terminal CLI, or an IDE extension. Each cloud task spins up an isolated sandbox preloaded with your GitHub repository, where GPT-5-Codex edits files, runs tests, linters, and type checkers, and commits results you can review or merge. The same ChatGPT account links ChatGPT, the Codex CLI, and the IDE extension so you can pair locally or delegate longer jobs to run in parallel.

Unlike inline autocomplete tools that suggest the next line, Codex treats software engineering as delegated work. You assign a scoped task, wait one to thirty minutes depending on complexity, and get verifiable citations from terminal logs and test output rather than a single pasted snippet. That trade-off favors refactors, test generation, and multi-file features over keystroke-level completion, which is why teams at Ramp, Duolingo, and Harvey use it for PR reviews and background chores they would otherwise postpone.

Developers on ChatGPT Plus, Pro, Business, and Enterprise plans can run Codex in ChatGPT with built-in worktrees, schedule recurring jobs like issue triage or CI monitoring, and teach team standards through Skills. Repositories can include AGENTS.md files that tell Codex how to run tests and follow project conventions. A Codex SDK embeds the same agent in custom workflows, and a Slack integration lets teams assign tasks from channels.