## Why
In the `shell_zsh_fork` flow, `codex-shell-escalation` receives the
executable path exactly as the shell passed it to `execve()`. That path
is not guaranteed to be absolute.
For commands such as `./scripts/hello-mbolin.sh`, if the shell was
launched with a different `workdir`, resolving the intercepted `file`
against the server process working directory makes policy checks and
skill matching inspect the wrong executable. This change pushes that fix
a step further by keeping the normalized path typed as `AbsolutePathBuf`
throughout the rest of the escalation pipeline.
That makes the absolute-path invariant explicit, so later code cannot
accidentally treat the resolved executable path as an arbitrary
`PathBuf`.
## What Changed
- record the wrapper process working directory as an `AbsolutePathBuf`
- update the escalation protocol so `workdir` is explicitly absolute
while `file` remains the raw intercepted exec path
- resolve a relative intercepted `file` against the request `workdir` as
soon as the server receives the request
- thread `AbsolutePathBuf` through `EscalationPolicy`,
`CoreShellActionProvider`, and command normalization helpers so the
resolved executable path stays type-checked as absolute
- replace the `path-absolutize` dependency in `codex-shell-escalation`
with `codex-utils-absolute-path`
- add a regression test that covers a relative `file` with a distinct
`workdir`
## Verification
- `cargo test -p codex-shell-escalation`
## Why
`codex-shell-escalation` exposed a `codex-core`-specific adapter layer
(`ShellActionProvider`, `ShellPolicyFactory`, and `run_escalate_server`)
that existed only to bridge `codex-core` to `EscalateServer`. That
indirection increased API surface and obscured crate ownership without
adding behavior.
This change moves orchestration into `codex-core` so boundaries are
clearer: `codex-shell-escalation` provides reusable escalation
primitives, and `codex-core` provides shell-tool policy decisions.
Admittedly, @pakrym rightfully requested this sort of cleanup as part of
https://github.com/openai/codex/pull/12649, though this avoids moving
all of `codex-shell-escalation` into `codex-core`.
## What changed
- Made `EscalateServer` public and exported it from `shell-escalation`.
- Removed the adapter layer from `shell-escalation`:
- deleted `shell-escalation/src/unix/core_shell_escalation.rs`
- removed exports for `ShellActionProvider`, `ShellPolicyFactory`,
`EscalationPolicyFactory`, and `run_escalate_server`
- Updated `core/src/tools/runtimes/shell/unix_escalation.rs` to:
- create `Stopwatch`/cancellation in `codex-core`
- instantiate `EscalateServer` directly
- implement `EscalationPolicy` directly on `CoreShellActionProvider`
Net effect: same escalation flow with fewer wrappers and a smaller
public API.
## Verification
- Manually reviewed the old vs. new escalation call flow to confirm
timeout/cancellation behavior and approval policy decisions are
preserved while removing wrapper types.
## Why
This PR switches the `shell_command` zsh-fork path over to
`codex-shell-escalation` so the new shell tool can use the shared
exec-wrapper/escalation protocol instead of the `zsh_exec_bridge`
implementation that was introduced in
https://github.com/openai/codex/pull/12052. `zsh_exec_bridge` relied on
UNIX domain sockets, which is not as tamper-proof as the FD-based
approach in `codex-shell-escalation`.
## What Changed
- Added a Unix zsh-fork runtime adapter in `core`
(`core/src/tools/runtimes/shell/unix_escalation.rs`) that:
- runs zsh-fork commands through
`codex_shell_escalation::run_escalate_server`
- bridges exec-policy / approval decisions into `ShellActionProvider`
- executes escalated commands via a `ShellCommandExecutor` that calls
`process_exec_tool_call`
- Updated `ShellRuntime` / `ShellCommandHandler` / tool spec wiring to
select a `shell_command` backend (`classic` vs `zsh-fork`) while leaving
the generic `shell` tool path unchanged.
- Removed the `zsh_exec_bridge`-based session service and deleted
`core/src/zsh_exec_bridge/mod.rs`.
- Moved exec-wrapper entrypoint dispatch to `arg0` by handling the
`codex-execve-wrapper` arg0 alias there, and removed the old
`codex_core::maybe_run_zsh_exec_wrapper_mode()` hooks from `cli` and
`app-server` mains.
- Added the needed `codex-shell-escalation` dependencies for `core` and
`arg0`.
## Tests
- `cargo test -p codex-core
shell_zsh_fork_prefers_shell_command_over_unified_exec`
- `cargo test -p codex-app-server turn_start_shell_zsh_fork --
--nocapture`
- verifies zsh-fork command execution and approval flows through the new
backend
- includes subcommand approve/decline coverage using the shared zsh
DotSlash fixture in `app-server/tests/suite/zsh`
- To test manually, I added the following to `~/.codex/config.toml`:
```toml
zsh_path = "/Users/mbolin/code/codex3/codex-rs/app-server/tests/suite/zsh"
[features]
shell_zsh_fork = true
```
Then I ran `just c` to run the dev build of Codex with these changes and
sent it the message:
```
run `echo $0`
```
And it replied with:
```
echo $0 printed:
/Users/mbolin/code/codex3/codex-rs/app-server/tests/suite/zsh
In this tool context, $0 reflects the script path used to invoke the shell, not just zsh.
```
so the tool appears to be wired up correctly.
## Notes
- The zsh subcommand-decline integration test now uses `rm` under a
`WorkspaceWrite` sandbox. The previous `/usr/bin/true` scenario is
auto-allowed by the new `shell-escalation` policy path, which no longer
produces subcommand approval prompts.
## Why
After removing `exec-server`, the next step is to wire a new shell tool
to `codex-rs/shell-escalation` directly.
That is blocked while `codex-shell-escalation` depends on `codex-core`,
because the new integration would require `codex-core` to depend on
`codex-shell-escalation` and create a dependency cycle.
This change ports the reusable pieces from the earlier prep work, but
drops the old compatibility shim because `exec-server`/MCP support is
already gone.
## What Changed
### Decouple `shell-escalation` from `codex-core`
- Introduce a crate-local `SandboxState` in `shell-escalation`
- Introduce a `ShellCommandExecutor` trait so callers provide process
execution/sandbox integration
- Update `EscalateServer::exec(...)` and `run_escalate_server(...)` to
use the injected executor
- Remove the direct `codex_core::exec::process_exec_tool_call(...)` call
from `shell-escalation`
- Remove the `codex-core` dependency from `codex-shell-escalation`
### Restore reusable policy adapter exports
- Re-enable `unix::core_shell_escalation`
- Export `ShellActionProvider` and `ShellPolicyFactory` from
`shell-escalation`
- Keep the crate root API simple (no `legacy_api` compatibility layer)
### Port socket fixes from the earlier prep commit
- Use `socket2::Socket::pair_raw(...)` for AF_UNIX socketpairs and
restore `CLOEXEC` explicitly on both endpoints
- Keep `CLOEXEC` cleared only on the single datagram client FD that is
intentionally passed across `exec`
- Clean up `tokio::AsyncFd::try_io(...)` error handling in the socket
helpers
## Verification
- `cargo shear`
- `cargo clippy -p codex-shell-escalation --tests`
- `cargo test -p codex-shell-escalation`
## Why
We already plan to remove the shell-tool MCP path, and doing that
cleanup first makes the follow-on `shell-escalation` work much simpler.
This change removes the last remaining reason to keep
`codex-rs/exec-server` around by moving the `codex-execve-wrapper`
binary and shared shell test fixtures to the crates/tests that now own
that functionality.
## What Changed
### Delete `codex-rs/exec-server`
- Remove the `exec-server` crate, including the MCP server binary,
MCP-specific modules, and its test support/test suite
- Remove `exec-server` from the `codex-rs` workspace and update
`Cargo.lock`
### Move `codex-execve-wrapper` into `codex-rs/shell-escalation`
- Move the wrapper implementation into `shell-escalation`
(`src/unix/execve_wrapper.rs`)
- Add the `codex-execve-wrapper` binary entrypoint under
`shell-escalation/src/bin/`
- Update `shell-escalation` exports/module layout so the wrapper
entrypoint is hosted there
- Move the wrapper README content from `exec-server` to
`shell-escalation/README.md`
### Move shared shell test fixtures to `app-server`
- Move the DotSlash `bash`/`zsh` test fixtures from
`exec-server/tests/suite/` to `app-server/tests/suite/`
- Update `app-server` zsh-fork tests to reference the new fixture paths
### Keep `shell-tool-mcp` as a shell-assets package
- Update `.github/workflows/shell-tool-mcp.yml` packaging so the npm
artifact contains only patched Bash/Zsh payloads (no Rust binaries)
- Update `shell-tool-mcp/package.json`, `shell-tool-mcp/src/index.ts`,
and docs to reflect the shell-assets-only package shape
- `shell-tool-mcp-ci.yml` does not need changes because it is already
JS-only
## Verification
- `cargo shear`
- `cargo clippy -p codex-shell-escalation --tests`
- `just clippy`
## Why
Shell execution refactoring in `exec-server` had become split between
duplicated code paths, which blocked a clean introduction of the new
reusable shell escalation flow. This commit creates a dedicated
foundation crate so later shell tooling changes can share one
implementation.
## What changed
- Added the `codex-shell-escalation` crate and moved the core escalation
pieces (`mcp` protocol/socket/session flow, policy glue) that were
previously in `exec-server` into it.
- Normalized `exec-server` Unix structure under a dedicated `unix`
module layout and kept non-Unix builds narrow.
- Wired crate/build metadata so `shell-escalation` is a first-class
workspace dependency for follow-on integration work.
## Verification
- Built and linted the stack at this commit point with `just clippy`.
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/12556).
* #12584
* #12583
* __->__ #12556
Michael Bolin ·