[SaladDay]

Summary

Programmatic tool calling on Codex failed in every Docker, microsandbox and E2B Environment: the model reported that codex-code-mode-host was missing. Native code_mode runs model-written scripts in that program, and Codex 0.153.4 looks for it beside its executable. The Runtime image copied only bin/codex from the pinned package. The native installer ships the whole package and was not affected.

• scripts/build-codex-runtime.sh checks and copies bin/codex-code-mode-host with bin/codex.
• The Codex and combined Runtime Dockerfiles install it at /usr/local/bin/codex-code-mode-host. The E2B template copies /usr/local/bin whole, so it follows.
• The Codex Runtime README and the maintainer guide (with zh hash) list the program.

Verification

• The released Runtime image (2026-10-12) has only codex in /usr/local/bin. With the host layered onto it, both programs sit there and codex --version reports 0.153.4.
• On mx, I ran the pinned codex exec against MiniMax-M2.7 with features.code_mode set, as the adapter does, and with the prompt echo code-mode-ok-$((6*7)):
  • Without the host: Code Mode is unavailable … host executable was not found. With code_mode_only, every call fails closed and the model reports the missing host, as in the bug report.
  • With the host beside codex: no warning, and with code_mode_only the script runs through code mode and returns code-mode-ok-42.
• generate-harness-catalog.py --check passes.

Release CI builds the images, so PR CI does not cover them.

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