MCP servers · OpenAI · MCP server
Connect Codex CLI to OpenAI
One line gives Codex CLI your OpenAI account as tools: 4 endpoints, generate image, create embedding, text to speech, called with your own connection. No key in the prompt, a receipt for every call, revoke Codex CLI's access alone any time.
Three steps
- Create a free 0n3 account and connect OpenAI. Paste a key or sign in; it lands in your vault, encrypted.
- Install 0n3 into Codex CLI. OpenAI's terminal agent reads 0n3 over Streamable HTTP with a token from your environment.
- Ask Codex CLI: whoami. Then: "Create an image in OpenAI".
Put the token in your environment
export ON3_TOKEN="<your 0n token>"
Add it to your shell profile so Codex finds it next time.
The line above carries a placeholder; 0n3.app/install mints a real key named for Codex CLI and fills it in.
What Codex CLI can then do in OpenAI
Generate image · Generate images with DALL-E1
Create an image
POST /images/generationsCreate embedding · Create text embeddings1
Create an embedding
POST /embeddingsText to speech · Convert text to speech1
Text to speech
POST /audio/speechGenerate text · Generate text completions0
Generate text completions
More · Everything else this app exposes.1
Chat completion
POST /chat/completionsOpenAI in other AI clients
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