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Documentation Index

Fetch the complete documentation index at: https://docs.modelstack.cc/llms.txt

Use this file to discover all available pages before exploring further.

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Overview

OpenAI’s original Codex API was deprecated. Current Codex workflows are tied to OpenAI’s modern model stack (for example GPT-5 Codex variants) and official OpenAI infrastructure.

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Installation

npm install -g @openai/codex

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ModelStack Compatibility

Compatibility depends on your Codex CLI version and whether it permits custom OpenAI-compatible base URLs. If your build supports custom base URL/env vars, configure:
  • Base URL: https://api.modelstack.cc/v1
  • API key: ModelStack API key
If not, use one of the tools with explicit OpenAI-compatible provider support (Cursor, Continue, Cline, Roo Code, Aider, Zed). For guaranteed ModelStack compatibility, use Aider or Continue.
Last verified: 2026-03-07