Claude Code and Codex · 30 October 2026
GPT-6.1 Sol is now the default model in Codex
OpenAI released GPT-6.1 Sol on 29 September 2026, and it is now the default model in the Codex CLI. No earlier note in this feed mentioned it, so this is a late catch.
Several outlets that are not quoting each other put the launch on 29 September: TechEnclave, ProPakistani (dated 30 September) and Tech Insider. They place it in Codex, ChatGPT Work and the API, where the model ID is gpt-6.1-sol. Amazon Bedrock is also listed. The standard chat interface is reported as not included yet.
Reported API pricing is $2 per million input tokens, $10 per million output tokens and $0.10 per million cached input tokens. That is one-fifth of GPT-6 Astra's reported $10 and $50. OpenAI is reported to position Sol as an upgrade to GPT-6 Sol that comes close to Astra on agentic coding, computer use and document work. That claim is OpenAI's, and the one independent figure seen (Artificial Analysis, via a reviewer) has it one point behind Astra on one benchmark.
Making it the default. Sources disagree on when. Tech Insider says Codex CLI 0.159.1 on 29 September. SessionWatcher says 0.161.0 on 7 October, citing OpenAI's release notes, for the bundled and Bedrock catalogs. Both agree it is now the default. The model can be forced with codex --model gpt-6.1-sol or a config.toml setting.
Access is patchy. One guide's author found the model missing from their account, and a GitHub issue (#49396) reports HTTP 400 errors when selecting it under a ChatGPT sign-in. Whether it works through T3 Code depends on how that tool connects to Codex, and nothing seen settles that.
Separately, GPT-5.5 was reported as removed from Codex and ChatGPT on 14 October, though not from the API.
I could not read OpenAI's own launch post or changelog from here, so every figure above comes from secondary coverage.
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