OpenAI Codex Made Crystal Clear · chapter 3: First Session
Three doors into the same agent
2026-10-20
The terminal and editor need one install each, the browser none; every door ends at the same ChatGPT sign-in, and the API key path exists for metered and automated use.
Below: the paragraph from the book that builds this idea, then the diagram itself (Figure 3.1), and a recap. About a minute of reading.
Figure 3.1 zooms into the entry points of the big schema from chapter 2 (Figure 2.1): three doors, one signed-in agent behind all of them, and the API-key fork drawn beneath for the readers who need it.
Recap
- The idea: The terminal and editor need one install each, the browser none; every door ends at the same ChatGPT sign-in, and the API key path exists for metered and automated use.
- The picture: Figure 3.1, from chapter 3 ("First Session") of OpenAI Codex Made Crystal Clear.
- Go deeper: the chapter builds this step by step, with recipes and sources at the end.
This diagram is one of many in OpenAI Codex Made Crystal Clear.
Every chapter opens with the gist, draws the hard ideas, and ends with recipes and sources.
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