Limitcast weekly update, 13 November: Codex and Grok catch up

In the weekly update on the Limitcast, version 0.19.4 of the optimizer, subagent receipts, and alerts were added to Codex and Grok. Both tools now share the same optimizer, receipts, and alerts as Claude Code. The optimizer was previously only available in version 0.19.0, which was not released on npm. Seven releases have been made since the previous update.

For Codex and Grok users, pruning proposals are now available. The optimizer proposes MCP servers and allows users to disable them in their project's config file. Codex also keeps its three built-in candidates, while Grok proposes servers but does not remove built-in tools.

Subagent receipts for Codex and Grok were also introduced. Codex computes receipts when the subagent stops, while Grok writes receipts after the stop hook. There were some issues with Grok's apply command not taking effect in 0.19.3, but it was fixed in 0.19.4 by writing a stub command that never runs. The receipt for Grok shows usage in API-equivalent dollars, while Codex receipts are computed based on the 5-hour window.

Additional features introduced include a fat-tool notice, fat-tool limit, and starting-context alert for Codex and Grok. The optimizer had a few fixes, such as correcting mistyped options and ensuring commands no longer undo each other. These fixes were necessary due to issues discovered during an audit.

To take advantage of the new hooks after upgrading, users need to run limitcast install --guard --alerts again, restart Claude Code, Codex, and Grok, and approve the new hooks in Codex. Some other updates include version 0.18.2, which now fails with "Unknown option" for mistyped options, 0.18.3, which prevents commands from undoing each other, and 0.19.2, which fixed optimizer issues related to learned command replacements and cache contamination.

The optimizer is opt-in, and users can refer to the optimizer guide for more information. The update was tested using isolated live sessions of Codex 0.169 and Grok 1.0.77. The Grok defect and Codex encryption issues were discovered through these tests, which showed that unit tests had passed but real-world usage revealed different results.