OpenAI launches Codex: the AI agent that writes code instead of engineers
OpenAI has launched a promo campaign for Codex under the slogan "It's time to fly" — an AI agent that takes on engineering tasks and solves them autonomously. Powered by GPT-5.5, Codex can run tests in parallel, write documentation, and suggest refactoring in separate sandbox environments — without human involvement. More than 4 million developers already use the tool every week, and 10,000 NVIDIA employees have been given enterprise access to it.
AI-processed from @OpenAI; edited by Hamidun News
OpenAI has released a cinematic video "It's time to fly" — a signal that Codex, their flagship AI agent for development, has moved from beta-tool mode to a full-fledged product.
What Codex can do in 2026
Codex is built on GPT-5.5 — OpenAI's first fully retrained base model since the release of GPT-4.5. The model was trained with agent scenarios in mind: it verifies its own code before delivering results and can conduct hundreds of sequential tool calls without human intervention. The key innovation is parallel execution in multiple sandbox environments simultaneously:
- runs a test suite in one environment
- generates documentation from diffs in parallel
- proposes refactoring in a third sandbox
- reads the screen and controls GUI applications for QA automation
- integrates into CLI, IDE, ChatGPT, and GitHub within a single account
While an engineer reviews the results, Codex is already working on the next task.
Numbers and scale
The product launch did not go unnoticed. At the time the promo was released, Codex had over 4 million active developers per week. NVIDIA provided access to the agent for 10,000 of its employees — not only engineers but also non-technical teams. Harness, a DevOps company, published a case study on OpenAI's website about how Codex is transitioning from assistant to full-fledged member of the engineering process — an "agent-first world" where an agent completes the task rather than suggesting how to complete it.
What it means
The "It's time to fly" slogan precisely describes the shift: Codex stops being smart autocomplete and becomes an autonomous executor. For development teams this means that routine engineering tasks — tests, documentation, small refactorings — are increasingly delegated to the agent, while people focus on architectural decisions and code review.
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Key Questions Answered
What Codex can do in 2026?
Codex is built on GPT-5.5 — OpenAI's first fully retrained base model since the release of GPT-4.5. The model was trained with agent scenarios in mind: it verifies its own code before delivering results and can conduct hundreds of sequential tool calls without human intervention. The key innovation is parallel execution in multiple sandbox environments simultaneously: runs a test suite in one environment generates documentation from diffs in parallel proposes refactoring in a third sandbox reads the screen and controls GUI applications for QA automation integrates into CLI,
What are the key details on Numbers and scale?
The product launch did not go unnoticed. At the time the promo was released, Codex had over 4 million active developers per week. NVIDIA provided access to the agent for 10,000 of its employees — not only engineers but also non-technical teams. Harness, a DevOps company, published a case study on OpenAI's website about how Codex is transitioning from assistant to full-fledged member of the engineering process — an "agent-first world" where an agent completes the task rather than suggesting how to complete it.
What it means?
The "It's time to fly" slogan precisely describes the shift: Codex stops being smart autocomplete and becomes an autonomous executor. For development teams this means that routine engineering tasks — tests, documentation, small refactorings — are increasingly delegated to the agent, while people focus on architectural decisions and code review.
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