Comparison

Claude Code vs Codex

Claude Code is Anthropic's CLI agent. Codex is OpenAI's. Both run from the terminal, both edit files in place, both can use tools. Pick based on which underlying model you trust for your work — and if you want to run them on the same repo at once for an A/B, do it inside Agentastic, which gives each one its own git worktree.

Who should choose each option

Claude Code

Choose Claude Code if you prefer Anthropic's models (Sonnet/Opus) and its tool-use behavior.

Codex

Choose Codex if you prefer OpenAI's models and its agent loop.

Feature comparison

Claude CodeCodex
VendorAnthropicOpenAI
Default modelClaude Sonnet / OpusGPT-class
PricingClaude Pro / Max / APIOpenAI API or ChatGPT
Worktree isolationManualManual
GUINo (CLI)No (CLI)

Pricing

Claude Code

Bundled with Claude Pro / Max / API.

Codex

OpenAI API or ChatGPT plan.

Using them together

Run them side by side in Agentastic — one Claude Code worktree and one Codex worktree on the same task — and compare the diffs they produce. This is the fastest way to decide which model fits a given codebase.

Frequently asked questions

Can I run both Claude Code and Codex at the same time?

Yes — easiest way is in two Agentastic worktrees on the same repo. They never see each other's changes until you merge.

Which one is better at long tasks?

It depends on the task and the model. Run them in parallel in Agentastic and compare the diffs.