Codex
OpenAI's agentic coding tool.
In daily use
Codex is OpenAI's coding agent, and the notable part of its design is that it is not tied to one surface. The same agent is reachable from the terminal, an IDE extension and the web, so a task started in one place can be inspected in another. Work runs in an isolated environment and comes back as a diff you review, which suits delegating well-scoped changes — implement this function, fix this failing suite — more than open-ended exploration. Running several independent tasks concurrently is where the model pays off.
Best for
- Delegating scoped coding tasks
- Working across terminal, IDE and web from one account
- Parallel work on independent changes
Key features
- Runs from the CLI, the IDE extension or the web, sharing the same agent
- Executes tasks in an isolated environment and returns a diff
- Handles several independent tasks at once
Why it matters
The multi-surface design means the same agent picks up a task wherever you are, instead of one agent per tool.
