Written by Ananya Bishnoi, Anthony Mocny, and Govind Kamtamneni, this post introduces codex-mini—a new, fast, and scalable Azure OpenAI model for code generation in CLI environments.

codex-mini: Fast, Scalable Code Generation for the CLI Era

Authors: Ananya Bishnoi, Anthony Mocny, Govind Kamtamneni

Microsoft has announced the general availability of Azure OpenAI’s codex-mini in Azure AI Foundry Models—a specialized, fine-tuned version of the o4-mini model designed for developer productivity in command-line interface (CLI) workflows.

Overview of codex-mini

codex-mini is engineered to bring rapid, instruction-following performance to CLI environments. It enables developers to automate shell commands, edit scripts, refactor repositories, and streamline terminal workflows. Key features of codex-mini include:

Optimized for Speed: Offers fast question-answering and code-editing with minimal overhead, ensuring efficient CLI automation.
Instruction-Following: Builds on Codex-1’s strengths in understanding natural language prompts, providing accurate, relevant shell commands and code snippets.
CLI-Native: Directly interprets natural language inputs and returns results as shell commands or code.
Long Context Support: Able to handle up to 200k-token input windows, making it suitable for ingesting and refactoring entire repositories.
Lightweight and Scalable: Designed for cost-effective deployment, with a small capacity footprint to suit scalable applications.
Cost Efficiency: Approximately 25% more cost-effective than GPT-4.1 for comparable input/output token workloads.
Codex CLI Compatibility: Integrates seamlessly with the codex-cli tool, enhancing existing developer workflows.

Pricing details for codex-mini and all Azure OpenAI models can be found on the Azure OpenAI pricing page.

Hands-On Usage: Deploying codex-mini

For developers looking for a practical guide to using codex-mini, Govind Kamtamneni provides a comprehensive walkthrough. This resource demonstrates how to:

Set up CLI tooling
Integrate codex-mini for automated engineering workflows
Connect with GitHub Actions
Operate within a secure, enterprise-grade Azure environment

Read the full guide here: Securely Turbo‑charge Your Software Delivery with the Codex Coding Agent on Azure OpenAI.

Open Source Collaboration

Microsoft’s team has actively contributed to the OpenAI Codex CLI in open source. Their pull request for improvements has been accepted and awaits final review: PR #1321.

Getting Started with codex-mini

Availability: codex-mini is accessible in East US2 and Sweden Central Azure regions, supporting Standard Global deployment.
API Access: Use the v1 preview API to build and experiment with codex-mini.
Model Registry: Details, documentation, and access are available at the Azure AI Foundry codex-mini model page.

Key Capabilities

codex-mini provides a set of developer-focused capabilities:

Streaming Outputs: Real-time code generation as you type
Function Calling: Automate and extend CLI behaviors
Structured Outputs: Generate and consume code and results in organized formats
Image Input: Supports multimodal workflows requiring code and image data

These features enable a wide range of scalable code generation tasks in command-line or terminal environments.

Summary

Developers can now leverage codex-mini for fast, reliable, and cost-effective code generation directly within their terminal. With support for large contexts, instruction following, broad compatibility with existing tools, and cost efficiency, codex-mini represents a significant advancement in AI-supported CLI development on Microsoft’s Azure platform.

For additional information, access, and detailed documentation, visit the codex-mini Azure AI Foundry model page.

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