zsh fork PR stack: - https://github.com/openai/codex/pull/12051 - https://github.com/openai/codex/pull/12052 👈 ### Summary This PR introduces a feature-gated native shell runtime path that routes shell execution through a patched zsh exec bridge, removing MCP-specific behavior from the shell hot path while preserving existing CommandExecution lifecycle semantics. When shell_zsh_fork is enabled, shell commands run via patched zsh with per-`execve` interception through EXEC_WRAPPER. Core receives wrapper IPC requests over a Unix socket, applies existing approval policy, and returns allow/deny before the subcommand executes. ### What’s included **1) New zsh exec bridge runtime in core** - Wrapper-mode entrypoint (maybe_run_zsh_exec_wrapper_mode) for EXEC_WRAPPER invocations. - Per-execution Unix-socket IPC handling for wrapper requests/responses. - Approval callback integration using existing core approval orchestration. - Streaming stdout/stderr deltas to existing command output event pipeline. - Error handling for malformed IPC, denial/abort, and execution failures. **2) Session lifecycle integration** SessionServices now owns a `ZshExecBridge`. Session startup initializes bridge state; shutdown tears it down cleanly. **3) Shell runtime routing (feature-gated)** When `shell_zsh_fork` is enabled: - Build execution env/spec as usual. - Add wrapper socket env wiring. - Execute via `zsh_exec_bridge.execute_shell_request(...)` instead of the regular shell path. - Non-zsh-fork behavior remains unchanged. **4) Config + feature wiring** - Added `Feature::ShellZshFork` (under development). - Added config support for `zsh_path` (optional absolute path to patched zsh): - `Config`, `ConfigToml`, `ConfigProfile`, overrides, and schema. - Session startup validates that `zsh_path` exists/usable when zsh-fork is enabled. - Added startup test for missing `zsh_path` failure mode. **5) Seatbelt/sandbox updates for wrapper IPC** - Extended seatbelt policy generation to optionally allow outbound connection to explicitly permitted Unix sockets. - Wired sandboxing path to pass wrapper socket path through to seatbelt policy generation. - Added/updated seatbelt tests for explicit socket allow rule and argument emission. **6) Runtime entrypoint hooks** - This allows the same binary to act as the zsh wrapper subprocess when invoked via `EXEC_WRAPPER`. **7) Tool selection behavior** - ToolsConfig now prefers ShellCommand type when shell_zsh_fork is enabled. - Added test coverage for precedence with unified-exec enabled.
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.
Network access and filesystem read/write roots are controlled by
SandboxPolicy. Seatbelt consumes the resolved policy and enforces it.
Seatbelt also supports macOS permission-profile extensions layered on top of
SandboxPolicy:
- no extension profile provided:
keeps legacy default preferences read access (
user-preference-read). - extension profile provided with no
macos_preferencesgrant: does not add preferences access clauses. macos_preferences = "readonly": enables cfprefs read clauses anduser-preference-read.macos_preferences = "readwrite": includes readonly clauses plususer-preference-writeand cfprefs shm write clauses.macos_automation = true: enables broad Apple Events send permissions.macos_automation = ["com.apple.Notes", ...]: enables Apple Events send only to listed bundle IDs.macos_accessibility = true: enablescom.apple.axservermach lookup.macos_calendar = true: enablescom.apple.CalendarAgentmach lookup.
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.