Codex CLI v0.159.1: GPT-6.1 Sol default, Bedrock catalogs#

Published September 29, 2026 by Alex Sorokoletov

Part of the Codex CLI Version Tracker series. | Codex on GitHub | Official Changelog

Codex CLI v0.159.1 is a patch release on the 0.159 line that follows v0.159.0. It promotes GPT-6.1 Sol to the default model in the bundled catalog and adds the same model to Amazon Bedrock's Mantle and Runtime catalogs, so Bedrock users can select it.^[1]

What Shipped#

The release notes tag both changes as backports onto the 0.159 line: one prepares the point release, the other carries the GPT-6.1 Sol Bedrock catalogs.^[1]

The Model Move#

The default flip is the practical part. Users who never touch model configuration are now on GPT-6.1 Sol the next time they start Codex, alongside the GPT-6 and GPT-5.6 entries the catalog already lists. GPT-6.1 Sol also lands in the Bedrock Mantle and Runtime catalogs, so teams routing Codex through AWS can select it. Codex ships an Amazon Bedrock provider path, so the new default is reachable there without going through the OpenAI API.

What This Tells Us#

v0.159.1 is a patch that sets the bundled default to GPT-6.1 Sol. Codex defaults to an OpenAI model, the way Claude Code defaults to Anthropic models and Gemini CLI to Google's, so each harness's default follows its own provider.

Shipping the same default into Amazon Bedrock's Mantle and Runtime catalogs means the teams running Codex under their own AWS billing and controls get the current model on the same release, not a lagging one. The same model is available on the OpenAI API path and the Bedrock path in this release.

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Sources#

1. Codex CLI release notes, rust-v0.159.1