OpenAI Adjusts Codex Model Context Window: 372k $\rightarrow$ 272k

"Backport refreshed bundled model metadata to 0.144" — The primary objective of Pull Request #33972.

In a recent update to the openai/codex repository, a technical adjustment was made regarding the model's metadata. Specifically, the context size for the Codex model has been scaled back. The capacity has been shifted from 372k to 272k.

🛠 Technical Implementation Details

The change was executed via Pull Request #33972, which was handled by the user sayan-oai. This PR served as a hotfix to ensure that the bundled model metadata was correctly refreshed for the 0.144 release.

Key Metadata Summary:

• Repository: openai/codex
• PR Number: #33972
• Merged By: sayan-oai
• Date of Merge: July 18, 2026
• Impact: Modified a single .json configuration file.

Merge Workflow

The following diagram illustrates the movement of code from the hotfix branch into the main release branch:

📊 Context Size Comparison

The reduction in the context window can be represented mathematically as a decrease in the total token limit:

$\Delta \text{Context} = 372,000 - 272,000 = 100,000 \text{ tokens}$

💻 Code and File Changes

The update involved a relatively small footprint in terms of lines of code, but a significant change in configuration. The diff showed:

• +64 lines added
• -54 lines removed

The changes were isolated to the metadata configuration. If one were to simulate the git operation, it would look like this:

git checkout release/0.144
git merge agent/hotfix-0.144-model-metadata
# Update bundled model metadata to 0.144

The specific modification occurred within the model_config.json (or similar .json metadata file), where the max_context_length parameter was updated.

🖼 Interface Reference

During the review of this PR, developers utilized various GitHub diff views to verify the metadata changes:

Figure 1: The Unified Diff view used to track line changes.

Figure 2: The Split Diff view for side-by-side comparison.

✅ PR Status Checklist

• Backport metadata to 0.144
• Update context size to 272k
• Merge agent/hotfix-0.144-model-metadata into release/0.144
• Verify .json file integrity

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Note: This update ensures that the model's reported capabilities align with its actual operational constraints in the 0.144 release cycle.