diff --git a/codex-rs/cli/src/debug_sandbox.rs b/codex-rs/cli/src/debug_sandbox.rs
index 513dccfa10..1ffc0eed0d 100644
--- a/codex-rs/cli/src/debug_sandbox.rs
+++ b/codex-rs/cli/src/debug_sandbox.rs
@@ -487,8 +487,22 @@ async fn run_command_under_windows_session(
     use codex_protocol::config_types::WindowsSandboxLevel;
     use codex_windows_sandbox::WindowsSandboxProxySettingsMode;
     use codex_windows_sandbox::WindowsSandboxSessionRequest;
+    use codex_windows_sandbox::resolve_windows_deny_read_paths;
     use codex_windows_sandbox::spawn_windows_sandbox_session_for_level;
 
+    // Setup reconciles persistent deny ACLs against this list. An empty list
+    // would discard the profile's denies, including on subsequent launches.
+    let (mut file_system, _) = permission_profile.to_runtime_permissions();
+    file_system.remove_skip_missing_path_entries();
+    let file_system = file_system.materialize_project_roots_with_workspace_roots(&workspace_roots);
+    let deny_read_paths = match resolve_windows_deny_read_paths(&file_system, &cwd) {
+        Ok(paths) => paths,
+        Err(err) => {
+            eprintln!("windows sandbox failed: {err}");
+            std::process::exit(1);
+        }
+    };
+
     let empty_paths: &[AbsolutePathBuf] = &[];
     let spawned = spawn_windows_sandbox_session_for_level(WindowsSandboxSessionRequest {
         permission_profile,
@@ -505,7 +519,7 @@ async fn run_command_under_windows_session(
         read_roots_override: None,
         read_roots_include_platform_defaults: false,
         write_roots_override: None,
-        deny_read_paths_override: empty_paths,
+        deny_read_paths_override: &deny_read_paths,
         deny_write_paths_override: empty_paths,
         tty: false,
         stdin_open: true,
diff --git a/codex-rs/core/BUILD.bazel b/codex-rs/core/BUILD.bazel
index c3b822481c..db994e81f2 100644
--- a/codex-rs/core/BUILD.bazel
+++ b/codex-rs/core/BUILD.bazel
@@ -12,6 +12,7 @@ codex_rust_crate(
         "//codex-rs/rmcp-client:test_streamable_http_server",
         "//codex-rs/cli:codex",
         "//codex-rs/windows-sandbox-rs:codex-command-runner",
+        "//codex-rs/windows-sandbox-rs:codex-windows-managed-deny-probe",
         "//codex-rs/windows-sandbox-rs:codex-windows-sandbox-setup",
     ],
     integration_compile_data_extra = glob(["assets/**"]),
diff --git a/codex-rs/core/tests/suite/windows_sandbox.rs b/codex-rs/core/tests/suite/windows_sandbox.rs
index cd22ea91c6..2276d33567 100644
--- a/codex-rs/core/tests/suite/windows_sandbox.rs
+++ b/codex-rs/core/tests/suite/windows_sandbox.rs
@@ -30,6 +30,7 @@ use std::collections::HashMap;
 use std::ffi::OsString;
 use std::path::Path;
 use std::path::PathBuf;
+use std::process::Command;
 use tempfile::TempDir;
 
 struct EnvVarGuard {
@@ -124,6 +125,143 @@ fn stage_windows_sandbox_helpers() -> anyhow::Result<()> {
     Ok(())
 }
 
+fn escape_toml_path(path: &Path) -> String {
+    path.display().to_string().replace('\\', "\\\\")
+}
+
+fn stage_windows_sandbox_cli(fixture_bin: &Path) -> anyhow::Result<(PathBuf, PathBuf)> {
+    std::fs::create_dir_all(fixture_bin)?;
+    let resources_dir = fixture_bin.join("codex-resources");
+    std::fs::create_dir_all(&resources_dir)?;
+
+    let codex_source = codex_utils_cargo_bin::cargo_bin("codex")?;
+    let codex = fixture_bin.join("codex.exe");
+    std::fs::copy(&codex_source, &codex)
+        .with_context(|| format!("copy {} to {}", codex_source.display(), codex.display()))?;
+    for helper_name in ["codex-windows-sandbox-setup", "codex-command-runner"] {
+        let helper = codex_utils_cargo_bin::cargo_bin(helper_name)?;
+        let destination = resources_dir.join(Path::new(helper_name).with_extension("exe"));
+        std::fs::copy(&helper, &destination)
+            .with_context(|| format!("copy {} to {}", helper.display(), destination.display()))?;
+    }
+
+    let probe_source = codex_utils_cargo_bin::cargo_bin("codex-windows-managed-deny-probe")?;
+    let probe = fixture_bin.join("managed-deny-probe.exe");
+    std::fs::copy(&probe_source, &probe)
+        .with_context(|| format!("copy {} to {}", probe_source.display(), probe.display()))?;
+    Ok((codex, probe))
+}
+
+fn assert_managed_deny_probe(output: &std::process::Output, launch: usize) -> anyhow::Result<()> {
+    let stdout = String::from_utf8_lossy(&output.stdout);
+    let stderr = String::from_utf8_lossy(&output.stderr);
+    assert!(
+        output.status.success(),
+        "managed deny probe launch {launch} failed: status={:?}; stdout={stdout}; stderr={stderr}",
+        output.status.code()
+    );
+    assert!(
+        stdout.contains("allowed-read:OK") && stdout.contains("allowed-import:OK"),
+        "managed deny probe launch {launch} lost allowed access: {stdout}"
+    );
+    assert!(
+        stdout.contains("denied-read:DENIED") && stdout.contains("denied-import:DENIED"),
+        "managed deny probe launch {launch} did not enforce denied access: {stdout}"
+    );
+    assert!(
+        !stdout.contains("UNEXPECTED_SUCCESS"),
+        "managed deny probe launch {launch} leaked denied content: {stdout}"
+    );
+    Ok(())
+}
+
+#[test]
+#[serial(codex_home)]
+fn windows_sandbox_cli_preserves_managed_deny_reads_across_launches() -> anyhow::Result<()> {
+    let codex_home =
+        codex_home_for_windows_sandbox_test("windows-cli-managed-deny-read-codex-home")?;
+
+    let fixture = TempDir::new()?;
+    let fixture_root = dunce::canonicalize(fixture.path())?;
+    let work = fixture_root.join("work");
+    let runtime = fixture_root.join("runtime");
+    let denied = runtime.join("denied");
+    let bin = fixture_root.join("bin");
+    std::fs::create_dir_all(&work)?;
+    std::fs::create_dir_all(&denied)?;
+    let (codex, probe) = stage_windows_sandbox_cli(&bin)?;
+
+    let allowed_text = runtime.join("allowed.txt");
+    let denied_text = denied.join("secret.txt");
+    let allowed_module = runtime.join("allowed.dll");
+    let denied_module = denied.join("secret.dll");
+    std::fs::write(&allowed_text, "ALLOW-CONTROL\n")?;
+    std::fs::write(&denied_text, "DENIED-CONTENT\n")?;
+    let system_root = std::env::var_os("SystemRoot").context("resolve SystemRoot")?;
+    let system_module = PathBuf::from(system_root)
+        .join("System32")
+        .join("version.dll");
+    std::fs::copy(&system_module, &allowed_module).with_context(|| {
+        format!(
+            "copy {} to {}",
+            system_module.display(),
+            allowed_module.display()
+        )
+    })?;
+    std::fs::copy(&system_module, &denied_module).with_context(|| {
+        format!(
+            "copy {} to {}",
+            system_module.display(),
+            denied_module.display()
+        )
+    })?;
+
+    std::fs::write(
+        codex_home.path().join("config.toml"),
+        format!(
+            "default_permissions = \"managed-deny-test\"\n\
+             \n\
+             [windows]\n\
+             sandbox = \"elevated\"\n\
+             \n\
+             [shell_environment_policy]\n\
+             inherit = \"all\"\n\
+             \n\
+             [permissions.managed-deny-test.filesystem]\n\
+             \":minimal\" = \"read\"\n\
+             \"{}\" = \"read\"\n\
+             \"{}\" = \"write\"\n\
+             \"{}\" = \"deny\"\n\
+             \n\
+             [permissions.managed-deny-test.network]\n\
+             enabled = false\n",
+            escape_toml_path(&fixture_root),
+            escape_toml_path(&work),
+            escape_toml_path(&denied),
+        ),
+    )?;
+
+    for launch in 1..=2 {
+        let output = Command::new(&codex)
+            .current_dir(&work)
+            .env("CODEX_HOME", codex_home.path())
+            .env("CODEX_WINDOWS_ALLOWED_TEXT", &allowed_text)
+            .env("CODEX_WINDOWS_DENIED_TEXT", &denied_text)
+            .env("CODEX_WINDOWS_ALLOWED_MODULE", &allowed_module)
+            .env("CODEX_WINDOWS_DENIED_MODULE", &denied_module)
+            .args(["sandbox", "--permission-profile"])
+            .arg("managed-deny-test")
+            .arg("--cd")
+            .arg(&work)
+            .arg("--")
+            .arg(&probe)
+            .output()?;
+        assert_managed_deny_probe(&output, launch)?;
+    }
+
+    Ok(())
+}
+
 #[tokio::test]
 #[serial(codex_home)]
 async fn windows_restricted_token_rejects_exact_and_glob_deny_read_policy() -> anyhow::Result<()> {
diff --git a/codex-rs/windows-sandbox-rs/Cargo.toml b/codex-rs/windows-sandbox-rs/Cargo.toml
index 401d9faa6c..62f969e8ab 100644
--- a/codex-rs/windows-sandbox-rs/Cargo.toml
+++ b/codex-rs/windows-sandbox-rs/Cargo.toml
@@ -18,6 +18,10 @@ path = "src/bin/setup_main/main.rs"
 name = "codex-command-runner"
 path = "src/bin/command_runner/main.rs"
 
+[[bin]]
+name = "codex-windows-managed-deny-probe"
+path = "src/bin/managed_deny_probe/main.rs"
+
 [lints]
 workspace = true
 
diff --git a/codex-rs/windows-sandbox-rs/src/bin/managed_deny_probe/main.rs b/codex-rs/windows-sandbox-rs/src/bin/managed_deny_probe/main.rs
new file mode 100644
index 0000000000..4535c9b957
--- /dev/null
+++ b/codex-rs/windows-sandbox-rs/src/bin/managed_deny_probe/main.rs
@@ -0,0 +1,13 @@
+// Keep the ACL probe independent of test-harness startup, which writes CODEX_HOME.
+#[cfg(target_os = "windows")]
+mod win;
+
+#[cfg(target_os = "windows")]
+fn main() {
+    win::main();
+}
+
+#[cfg(not(target_os = "windows"))]
+fn main() {
+    panic!("codex-windows-managed-deny-probe is Windows-only");
+}
diff --git a/codex-rs/windows-sandbox-rs/src/bin/managed_deny_probe/win.rs b/codex-rs/windows-sandbox-rs/src/bin/managed_deny_probe/win.rs
new file mode 100644
index 0000000000..159268d84c
--- /dev/null
+++ b/codex-rs/windows-sandbox-rs/src/bin/managed_deny_probe/win.rs
@@ -0,0 +1,101 @@
+use std::ffi::c_void;
+use std::io::Write as _;
+use std::os::windows::ffi::OsStrExt;
+use std::path::Path;
+use std::path::PathBuf;
+
+#[link(name = "kernel32")]
+unsafe extern "system" {
+    #[link_name = "LoadLibraryW"]
+    fn load_library_w(file_name: *const u16) -> *mut c_void;
+    #[link_name = "FreeLibrary"]
+    fn free_library(module: *mut c_void) -> i32;
+}
+
+fn load_library(path: &Path) -> std::io::Result<()> {
+    let wide_path: Vec<u16> = path
+        .as_os_str()
+        .encode_wide()
+        .chain(std::iter::once(0))
+        .collect();
+    // SAFETY: `wide_path` is NUL-terminated and remains alive for the call.
+    let module = unsafe { load_library_w(wide_path.as_ptr()) };
+    if module.is_null() {
+        return Err(std::io::Error::last_os_error());
+    }
+    // SAFETY: `module` is a non-null handle returned by `LoadLibraryW` above.
+    if unsafe { free_library(module) } == 0 {
+        return Err(std::io::Error::last_os_error());
+    }
+    Ok(())
+}
+
+fn access_was_denied(err: &std::io::Error) -> bool {
+    err.kind() == std::io::ErrorKind::PermissionDenied || err.raw_os_error() == Some(5)
+}
+
+fn probe_path(key: &str) -> PathBuf {
+    let Some(value) = std::env::var_os(key) else {
+        eprintln!("managed deny probe is missing {key}");
+        probe_exit(/*code*/ 21);
+    };
+    PathBuf::from(value)
+}
+
+fn probe_exit(code: i32) -> ! {
+    let _ = std::io::stdout().flush();
+    let _ = std::io::stderr().flush();
+    std::process::exit(code);
+}
+
+pub(super) fn main() {
+    let allowed_text = probe_path("CODEX_WINDOWS_ALLOWED_TEXT");
+    let denied_text = probe_path("CODEX_WINDOWS_DENIED_TEXT");
+    let allowed_module = probe_path("CODEX_WINDOWS_ALLOWED_MODULE");
+    let denied_module = probe_path("CODEX_WINDOWS_DENIED_MODULE");
+
+    match std::fs::read_to_string(&allowed_text) {
+        Ok(contents) if contents.trim() == "ALLOW-CONTROL" => println!("allowed-read:OK"),
+        Ok(_) => {
+            eprintln!("allowed read returned unexpected contents");
+            probe_exit(/*code*/ 21);
+        }
+        Err(err) => {
+            eprintln!("allowed read failed: {err}");
+            probe_exit(/*code*/ 21);
+        }
+    }
+    if let Err(err) = load_library(&allowed_module) {
+        eprintln!("allowed import failed: {err}");
+        probe_exit(/*code*/ 21);
+    }
+    println!("allowed-import:OK");
+
+    let mut failures = 0;
+    match std::fs::read(&denied_text) {
+        Ok(_) => {
+            println!("denied-read:UNEXPECTED_SUCCESS");
+            failures += 1;
+        }
+        Err(err) if access_was_denied(&err) => println!("denied-read:DENIED"),
+        Err(err) => {
+            eprintln!("denied read failed for a non-access reason: {err}");
+            probe_exit(/*code*/ 21);
+        }
+    }
+    match load_library(&denied_module) {
+        Ok(()) => {
+            println!("denied-import:UNEXPECTED_SUCCESS");
+            failures += 1;
+        }
+        Err(err) if access_was_denied(&err) => println!("denied-import:DENIED"),
+        Err(err) => {
+            eprintln!("denied import failed for a non-access reason: {err}");
+            probe_exit(/*code*/ 21);
+        }
+    }
+
+    if failures != 0 {
+        probe_exit(/*code*/ 20);
+    }
+}