This PR introduces a skill-expansion mechanism for mentions so nested or skill or connection mentions are expanded if present in skills invoked by the user. This keeps behavior aligned with existing mention handling while extending coverage to deeper scenarios. With these changes, users can create skills that invoke connectors, and skills that invoke other skills. Replaces #10863, which is not needed with the addition of [search_tool_bm25](https://github.com/openai/codex/issues/10657)
codex-core
This crate implements the business logic for Codex. It is designed to be used by the various Codex UIs written in Rust.
Dependencies
Note that codex-core makes some assumptions about certain helper utilities being available in the environment. Currently, this support matrix is:
macOS
Expects /usr/bin/sandbox-exec to be present.
When using the workspace-write sandbox policy, the Seatbelt profile allows
writes under the configured writable roots while keeping .git (directory or
pointer file), the resolved gitdir: target, and .codex read-only.
Linux
Expects the binary containing codex-core to run the equivalent of codex sandbox linux (legacy alias: codex debug landlock) when arg0 is codex-linux-sandbox. See the codex-arg0 crate for details.
All Platforms
Expects the binary containing codex-core to simulate the virtual apply_patch CLI when arg1 is --codex-run-as-apply-patch. See the codex-arg0 crate for details.