OpenAI DevDay: Codex, No‑Code Agents, Apps SDK

08 Oct 2025

OpenAI’s DevDay release shifts how AI is built: the company introduced Codex as an AI “co‑worker” (it can write tests, review PRs and even accept Slack tasks via @Codex), a no‑code AgentKit/Agent Builder visual canvas for composing multi‑agent workflows, and an Apps SDK that lets developers embed interactive UIs (maps, forms, video players) directly inside ChatGPT. OpenAI says Codex wrote roughly 80% of the new Agent Builder tool in under six weeks — an example of AI tooling accelerating its own development.

Demos showed rapid, production-style workflows: voice-driven engineering that had Codex generate real‑time functions to control cameras and stage lighting, and a customer‑service agent built and deployed in about 8 minutes using the visual builder. OpenAI also released new API models (including Sora 2 and GPT‑5 Pro) alongside documentation and prompting guidance. The newsletter frames the release as a turning point: building complex, agentic software moves from heavyweight engineering projects to rapid prototyping, lowering the barrier for founders and turning many knowledge workers into designers/architects of automated agents.

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