Codex is OpenAI’s coding agent for the terminal, and the CLI is open source under Apache 2.0. It is one surface of the wider Codex product, which also spans an IDE extension, cloud environments, the web, and iOS.
models and pricing
Codex defaults to GPT-6.1 Sol and switches models with /model; the
lineup depends on your plan. Sign in with a ChatGPT account on any plan
from Free to Pro (from $100/mo) with credit-based usage, or sign in with
an API key and pay standard token rates. Its config also accepts custom
model providers, and --oss runs local open-source models through Ollama
or LM Studio.
what it’s good at
Codex pairs OS-level sandboxing with granular approval and permission
modes, so risky commands stay gated. codex cloud hands tasks to cloud
environments and includes a dedicated code-review mode. AGENTS.md project
instructions, skills, slash commands, lifecycle hooks, and MCP support
round out the same extension surface its competitors are converging on.
Codex in crystl
Codex runs in a crystl shard the same way any other agent does: its permission requests reach the approval cards, and its rollout transcripts feed history, turn stats, and the chat dock.
Parity with Claude Code is the goal rather than a guarantee — where a host surface only exists for one agent, the docs for that feature say so.