Codex in Agents SDK

OpenAI has started exposing Codex through its Agents software development kit, letting developers plug its coding agent into custom workflows and remote sandboxes. (developers.openai.com) Codex is OpenAI’s coding agent, a tool that can plan changes, write code, run commands, and continue work across sessions from the terminal, an editor, or the web. OpenAI’s developer docs say the software development kit can control Codex threads programmatically, including starting a thread, resuming it later, and embedding it in internal tools or continuous integration pipelines. (openai.com; developers.openai.com) The new Agents software development kit path works by running Codex as a Model Context Protocol server, then connecting that server to an agent built with OpenAI’s Agents software development kit. OpenAI’s guide says developers can set approval rules for shell commands, choose a working directory, and set sandbox modes including read-only, workspace-write, and danger-full-access. (developers.openai.com) A sandbox is a rented computer the agent can use without touching your laptop, and Blaxel is pitching that layer as a way to give agents their own cloud machine. Blaxel’s documentation says its sandboxes preserve filesystem state and running processes, scale to zero when idle, and can be paired with OpenAI Agents software development kit deployments. (docs.blaxel.ai; docs.blaxel.ai) OpenAI is pairing that technical rollout with new pricing aimed at heavier coding use. Its Codex pricing page says a new Pro plan starts at $100 a month, sits between Plus at $20 and the existing $200 Pro option, and currently offers 10 times the Plus Codex rate limits through May 31, 2026, versus a standard 5 times level. (developers.openai.com; help.openai.com) OpenAI’s help pages describe the $100 plan as “built for real projects,” with higher limits than Plus and access to advanced models, while the $200 plan remains the highest-usage option for parallel, always-on work. The company’s pricing page also says Codex is now included across Free, Go, Plus, Pro, Business, Edu, and Enterprise plans, with API pricing available for automation in shared environments. (help.openai.com; developers.openai.com) The usage numbers behind the push are moving fast. Sam Altman said on April 7 that Codex had reached 3 million weekly users and that OpenAI was resetting usage limits to mark each additional million users up to 10 million; OpenAI’s community announcement the next day said the subscription changes were meant to support “the growing use of Codex.” (technobezz.com; community.openai.com) This build-out extends a product shift that has been underway since 2025. When OpenAI declared Codex generally available on October 6, 2025, it added a software development kit, Slack integration, and admin controls, and said daily Codex usage had grown more than 10 times since early August. (openai.com) OpenAI’s pitch is increasingly about agentic coding, meaning software agents that do more than autocomplete a line and instead take on a whole task with tools, memory, and a machine to work on. Its Codex site now describes the app as a command center for multi-agent workflows with built-in worktrees and cloud environments, while the software development kit and Blaxel tutorials show how that model can be wired into custom engineering systems. (openai.com; docs.blaxel.ai) The immediate test is whether developers treat Codex as another coding assistant or as infrastructure for software teams. OpenAI’s product pages now price, package, and document it more like a system that runs work than a chatbot that answers questions. (openai.com; developers.openai.com)