OpenAI Codex has undergone major changes with the GPT-5.6 update. Here is what developers think after months of using the new version.
What developers love:
Sandbox execution is Codex unique advantage. Codex runs generated code in isolated containers before showing results. Developers working with untrusted code or experimenting with new libraries feel safer with Codex.
The 64-subagent SOL architecture in GPT-5.6 is genuinely impressive for complex parallel tasks. Codex can spawn dozens of agents to work on different parts of a problem simultaneously.
What frustrates them:
Tool call bugs have been a persistent issue with GPT-5.6. The model sometimes hallucinates function calls or makes incorrect tool selections. The community has documented hundreds of bug reports.
Pricing is higher than competitors for heavy usage. Codex per-request pricing adds up fast for developers running frequent agentic sessions.
The verdict:
Codex is the best choice for security-conscious developers and teams running untrusted code. For general development, Claude Code and Cursor offer better value. The sandbox is unique but most developers do not need it daily.
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