Codex is now the recommended agent in JetBrains IDEs

JetBrains has selected OpenAI's Codex as the default recommended coding agent in JetBrains IDEs, replacing the previous approach where users had to manually choose an agent. The decision was based on a structured evaluation using real-world software engineering tasks across Java (225 tasks), C# (38 tasks), and Python (90 tasks) ecosystems. Candidates were ranked on solve rate, cost per task, and end-to-end latency. After a close offline benchmark between Codex (GPT-5.4 mini with medium reasoning) and Junie (Gemini 3 Flash), an online A/B test with real users tipped the decision in Codex's favor based on activation, churn, and failure rate signals. Users can still switch to any other supported agent, including Junie, Claude Agent, or any ACP-compatible agent, at any time. The recommendation will be re-evaluated as models and benchmarks evolve.

Source: https://blog.jetbrains.com/ai/2026/06/codex-is-now-the-recommended-agent-in-jetbrains-ai. 8 Sync News only summarizes and links out; content copyright belongs to the authors and original sources.