Record Windows MXC availability (#42094)

## What changed

- Probe whether the native Windows MXC process security environment is usable
  when selecting a sandbox.
- Emit `codex.windows_mxc.available` at most once per process, labeled with the
  probe result.
- Add the MXC workspace dependencies for Cargo and Bazel, and pin
  `tracelogging` to a version compatible with the GNU Windows toolchain.

GitOrigin-RevId: d7cfeed6f0333feda5764e1ee44fe5bbd50f9a58

codex-rs/Cargo.lock

@@ -421,6 +421,27 @@ dependencies = [
  "wiremock",
 ]
 
+[[package]]
+name = "appcontainer_common"
+version = "0.8.0"
+source = "git+https://github.com/microsoft/mxc?rev=6cd3d58f05d3447e67109cfb75e042803b843ca4#6cd3d58f05d3447e67109cfb75e042803b843ca4"
+dependencies = [
+ "flatbuffers",
+ "getrandom 0.2.17",
+ "learning_mode_core",
+ "learning_mode_windows",
+ "process_security_environment_spec",
+ "sandbox_spec",
+ "serde",
+ "serde_json",
+ "thiserror 2.0.18",
+ "widestring",
+ "windows 0.62.2",
+ "windows-core 0.62.2",
+ "winreg 0.55.0",
+ "wxc_common",
+]
+
 [[package]]
 name = "approx"
 version = "0.5.1"
@@ -1730,6 +1751,12 @@ version = "1.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6e4de3bc4ea267985becf712dc6d9eed8b04c953b3fcfb339ebc87acd9804901"
 
+[[package]]
+name = "cidr"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "579504560394e388085d0c080ea587dfa5c15f7e251b4d5247d1e1a61d1d6928"
+
 [[package]]
 name = "cipher"
 version = "0.4.4"
@@ -4194,7 +4221,9 @@ name = "codex-sandboxing"
 version = "0.0.0"
 dependencies = [
  "anyhow",
+ "appcontainer_common",
  "codex-network-proxy",
+ "codex-otel",
  "codex-protocol",
  "codex-utils-absolute-path",
  "codex-utils-home-dir",
@@ -4208,6 +4237,7 @@ dependencies = [
  "serde_json",
  "tempfile",
  "tokio",
+ "tracelogging",
  "tracing",
  "url",
  "which 8.0.0",
@@ -6562,6 +6592,16 @@ version = "0.5.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1d674e81391d1e1ab681a28d99df07927c6d4aa5b027d7da16ba32d1d21ecd99"
 
+[[package]]
+name = "flatbuffers"
+version = "25.12.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "35f6839d7b3b98adde531effaf34f0c2badc6f4735d26fe74709d8e513a96ef3"
+dependencies = [
+ "bitflags 2.13.1",
+ "rustc_version",
+]
+
 [[package]]
 name = "flate2"
 version = "1.1.8"
@@ -9125,6 +9165,32 @@ version = "1.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
 
+[[package]]
+name = "learning_mode_core"
+version = "0.8.0"
+source = "git+https://github.com/microsoft/mxc?rev=6cd3d58f05d3447e67109cfb75e042803b843ca4#6cd3d58f05d3447e67109cfb75e042803b843ca4"
+dependencies = [
+ "same-file",
+ "serde",
+ "serde_json",
+ "sha2 0.10.9",
+ "tempfile",
+ "thiserror 2.0.18",
+]
+
+[[package]]
+name = "learning_mode_windows"
+version = "0.8.0"
+source = "git+https://github.com/microsoft/mxc?rev=6cd3d58f05d3447e67109cfb75e042803b843ca4#6cd3d58f05d3447e67109cfb75e042803b843ca4"
+dependencies = [
+ "learning_mode_core",
+ "sha2 0.10.9",
+ "thiserror 2.0.18",
+ "windows 0.62.2",
+ "windows-core 0.62.2",
+ "wxc_common",
+]
+
 [[package]]
 name = "leb128fmt"
 version = "0.1.0"
@@ -9581,6 +9647,25 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "mxc_config_contract"
+version = "0.8.0"
+source = "git+https://github.com/microsoft/mxc?rev=6cd3d58f05d3447e67109cfb75e042803b843ca4#6cd3d58f05d3447e67109cfb75e042803b843ca4"
+dependencies = [
+ "serde",
+ "serde_json",
+ "thiserror 2.0.18",
+]
+
+[[package]]
+name = "mxc_telemetry"
+version = "0.8.0"
+source = "git+https://github.com/microsoft/mxc?rev=6cd3d58f05d3447e67109cfb75e042803b843ca4#6cd3d58f05d3447e67109cfb75e042803b843ca4"
+dependencies = [
+ "tracelogging",
+ "uuid",
+]
+
 [[package]]
 name = "native-tls"
 version = "0.2.14"
@@ -10912,6 +10997,14 @@ dependencies = [
  "windows 0.62.2",
 ]
 
+[[package]]
+name = "process_security_environment_spec"
+version = "0.8.0"
+source = "git+https://github.com/microsoft/mxc?rev=6cd3d58f05d3447e67109cfb75e042803b843ca4#6cd3d58f05d3447e67109cfb75e042803b843ca4"
+dependencies = [
+ "flatbuffers",
+]
+
 [[package]]
 name = "prodash"
 version = "31.0.0"
@@ -12251,6 +12344,14 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "sandbox_spec"
+version = "0.8.0"
+source = "git+https://github.com/microsoft/mxc?rev=6cd3d58f05d3447e67109cfb75e042803b843ca4#6cd3d58f05d3447e67109cfb75e042803b843ca4"
+dependencies = [
+ "flatbuffers",
+]
+
 [[package]]
 name = "scc"
 version = "2.4.0"
@@ -14506,6 +14607,21 @@ version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8df9b6e13f2d32c91b9bd719c00d1958837bc7dec474d94952798cc8e69eeec3"
 
+[[package]]
+name = "tracelogging"
+version = "1.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e4314470f3f54b29d582ff6776fceb7c819b023141828d559f19c790cee40e94"
+dependencies = [
+ "tracelogging_macros",
+]
+
+[[package]]
+name = "tracelogging_macros"
+version = "1.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "95e2d891464ff33bc1814c4cbbb251bae7800458b1efdb6ac8b7c01ee6382563"
+
 [[package]]
 name = "tracing"
 version = "0.1.44"
@@ -14852,6 +14968,12 @@ version = "2.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7eec5d1121208364f6793f7d2e222bf75a915c19557537745b195b253dd64217"
 
+[[package]]
+name = "unicode-general-category"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0b993bddc193ae5bd0d623b49ec06ac3e9312875fdae725a975c51db1cc1677f"
+
 [[package]]
 name = "unicode-ident"
 version = "1.0.22"
@@ -16008,6 +16130,16 @@ dependencies = [
  "windows-sys 0.48.0",
 ]
 
+[[package]]
+name = "winreg"
+version = "0.55.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cb5a765337c50e9ec252c2069be9bf91c7df47afb103b642ba3a53bf8101be97"
+dependencies = [
+ "cfg-if",
+ "windows-sys 0.59.0",
+]
+
 [[package]]
 name = "winsafe"
 version = "0.0.19"
@@ -16155,6 +16287,30 @@ version = "0.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9edde0db4769d2dc68579893f2306b26c6ecfbe0ef499b013d731b7b9247e0b9"
 
+[[package]]
+name = "wxc_common"
+version = "0.8.0"
+source = "git+https://github.com/microsoft/mxc?rev=6cd3d58f05d3447e67109cfb75e042803b843ca4#6cd3d58f05d3447e67109cfb75e042803b843ca4"
+dependencies = [
+ "base64 0.22.1",
+ "cidr",
+ "getrandom 0.2.17",
+ "libc",
+ "mxc_config_contract",
+ "mxc_telemetry",
+ "semver",
+ "serde",
+ "serde_json",
+ "serde_path_to_error",
+ "thiserror 2.0.18",
+ "unicode-general-category",
+ "url",
+ "widestring",
+ "windows 0.62.2",
+ "windows-core 0.62.2",
+ "winreg 0.55.0",
+]
+
 [[package]]
 name = "x11rb"
 version = "0.13.2"

codex-rs/Cargo.toml

@@ -296,6 +296,7 @@ mcp_test_support = { path = "mcp-server/tests/common" }
 age = "0.11.1"
 ansi-to-tui = "8.0.1"
 anyhow = "1"
+appcontainer_common = { git = "https://github.com/microsoft/mxc", rev = "6cd3d58f05d3447e67109cfb75e042803b843ca4" }
 arboard = { version = "3", features = ["wayland-data-control"] }
 arc-swap = "1.9.0"
 assert_cmd = "2"

codex-rs/deny.toml

@@ -313,6 +313,7 @@ allow-git = [
     "https://github.com/dzbarsky/rules_rust",
     "https://github.com/helix-editor/nucleo.git",
     "https://github.com/juberti-oai/rust-sdks.git",
+    "https://github.com/microsoft/mxc",
     "https://github.com/openai-oss-forks/crossterm",
     "https://github.com/openai-oss-forks/tokio-tungstenite",
     "https://github.com/openai-oss-forks/tungstenite-rs",

codex-rs/sandboxing/Cargo.toml

@@ -12,6 +12,10 @@ doctest = false
 [lints]
 workspace = true
 
+# This direct dependency pins MXC's transitive ETW dependency for Windows GNU linking.
+[package.metadata.cargo-shear]
+ignored = ["tracelogging"]
+
 [dependencies]
 anyhow = { workspace = true }
 codex-network-proxy = { workspace = true }
@@ -30,7 +34,11 @@ url = { workspace = true }
 which = { workspace = true }
 
 [target.'cfg(windows)'.dependencies]
+appcontainer_common = { workspace = true }
+codex-otel = { workspace = true }
 codex-utils-home-dir = { workspace = true }
+# 1.2.4 imports OneCore_apiset, which the GNU Windows toolchain does not ship.
+tracelogging = "=1.2.3"
 
 [dev-dependencies]
 anyhow = { workspace = true }

codex-rs/sandboxing/src/lib.rs

@@ -10,6 +10,8 @@ mod spawn;
 mod terminal_queries;
 mod violation;
 mod windows;
+#[cfg(windows)]
+mod windows_mxc;
 
 #[cfg(target_os = "linux")]
 pub use bwrap::find_system_bwrap_in_path;

codex-rs/sandboxing/src/manager.rs

@@ -301,6 +301,9 @@ impl SandboxManager {
         windows_sandbox_level: WindowsSandboxLevel,
         has_managed_network_requirements: bool,
     ) -> SandboxType {
+        #[cfg(windows)]
+        crate::windows_mxc::record_availability_once();
+
         if self.should_sandbox(permission_profile, pref, has_managed_network_requirements) {
             get_platform_sandbox(windows_sandbox_level != WindowsSandboxLevel::Disabled)
                 .unwrap_or(SandboxType::None)

codex-rs/sandboxing/src/windows_mxc.rs

@@ -0,0 +1,28 @@
+//! Native Windows MXC capability discovery and availability metrics.
+//! Probing is cached upstream; reporting happens at most once per process.
+
+use appcontainer_common::base_container_runner::BaseContainerRunner;
+use std::sync::atomic::AtomicBool;
+use std::sync::atomic::Ordering;
+
+static AVAILABILITY_RECORDED: AtomicBool = AtomicBool::new(false);
+
+// tracelogging 1.2.3 leaves its ETW import library to the application. These
+// APIs are exported by Advapi32 in both the MSVC and GNU Windows toolchains.
+#[link(name = "advapi32")]
+unsafe extern "system" {}
+
+pub(super) fn record_availability_once() {
+    // Probe actual PSEC create/close support; symbol presence alone also
+    // succeeds on transitional Windows builds where MXC is not enabled.
+    let available = BaseContainerRunner::is_process_security_environment_usable();
+    if let Some(metrics) = codex_otel::global()
+        && !AVAILABILITY_RECORDED.swap(true, Ordering::Relaxed)
+    {
+        let _ = metrics.counter(
+            "codex.windows_mxc.available",
+            /*inc*/ 1,
+            &[("available", if available { "true" } else { "false" })],
+        );
+    }
+}