diff --git a/codex-rs/windows-sandbox-rs/src/bin/setup_main/win.rs b/codex-rs/windows-sandbox-rs/src/bin/setup_main/win.rs
index d862f33eca..4043bda9f6 100644
--- a/codex-rs/windows-sandbox-rs/src/bin/setup_main/win.rs
+++ b/codex-rs/windows-sandbox-rs/src/bin/setup_main/win.rs
@@ -22,6 +22,7 @@ use codex_windows_sandbox::install_wfp_filters;
 use codex_windows_sandbox::is_command_cwd_root;
 use codex_windows_sandbox::load_or_create_cap_sids;
 use codex_windows_sandbox::log_note;
+use codex_windows_sandbox::materialize_setup_dependencies;
 use codex_windows_sandbox::path_mask_allows;
 use codex_windows_sandbox::sandbox_bin_dir;
 use codex_windows_sandbox::sandbox_dir;
@@ -918,6 +919,24 @@ fn run_setup_full(payload: &Payload, log: &mut File, sbx_dir: &Path) -> Result<(
         if legacy_users.exists() {
             let _ = std::fs::remove_file(&legacy_users);
         }
+        let materialized = materialize_setup_dependencies(&payload.codex_home, Some(sbx_dir))
+            .map_err(|err| {
+                anyhow::Error::new(SetupFailure::new(
+                    SetupErrorCode::HelperDependencyMaterializationFailed,
+                    format!(
+                        "materialize sandbox helper executables into {} failed: {err:#}",
+                        sandbox_bin_dir(&payload.codex_home).display()
+                    ),
+                ))
+            })?;
+        log_line(
+            log,
+            &format!(
+                "materialized {} helper executable(s) into {}",
+                materialized.len(),
+                sandbox_bin_dir(&payload.codex_home).display()
+            ),
+        )?;
     }
 
     unsafe {
diff --git a/codex-rs/windows-sandbox-rs/src/helper_materialization.rs b/codex-rs/windows-sandbox-rs/src/helper_materialization.rs
index 8f0b5cb83b..5a65bb6896 100644
--- a/codex-rs/windows-sandbox-rs/src/helper_materialization.rs
+++ b/codex-rs/windows-sandbox-rs/src/helper_materialization.rs
@@ -114,6 +114,44 @@ pub fn resolve_current_exe_for_launch(codex_home: &Path, fallback_executable: &s
     }
 }
 
+pub fn materialize_setup_dependencies(
+    codex_home: &Path,
+    log_dir: Option<&Path>,
+) -> Result<Vec<PathBuf>> {
+    let mut materialized = Vec::new();
+
+    let source = std::env::current_exe().context("resolve current executable for setup copy")?;
+    let file_name = source.file_name().ok_or_else(|| {
+        anyhow!(
+            "current executable has no file name for setup copy: {}",
+            source.display()
+        )
+    })?;
+    let destination = helper_bin_dir(codex_home).join(file_name);
+    let outcome = copy_from_source_if_needed(&source, &destination)?;
+    let action = match outcome {
+        CopyOutcome::Reused => "reused",
+        CopyOutcome::ReCopied => "recopied",
+    };
+    log_note(
+        &format!(
+            "helper copy: {action} setup-helper source={} destination={}",
+            source.display(),
+            destination.display()
+        ),
+        log_dir,
+    );
+    materialized.push(destination);
+
+    materialized.push(copy_helper_if_needed(
+        HelperExecutable::CommandRunner,
+        codex_home,
+        log_dir,
+    )?);
+
+    Ok(materialized)
+}
+
 pub(crate) fn copy_helper_if_needed(
     kind: HelperExecutable,
     codex_home: &Path,
diff --git a/codex-rs/windows-sandbox-rs/src/lib.rs b/codex-rs/windows-sandbox-rs/src/lib.rs
index 78081b5e1f..975ec691b8 100644
--- a/codex-rs/windows-sandbox-rs/src/lib.rs
+++ b/codex-rs/windows-sandbox-rs/src/lib.rs
@@ -131,6 +131,8 @@ pub use elevated_impl::ElevatedSandboxCaptureRequest;
 #[cfg(target_os = "windows")]
 pub use elevated_impl::run_windows_sandbox_capture as run_windows_sandbox_capture_elevated;
 #[cfg(target_os = "windows")]
+pub use helper_materialization::materialize_setup_dependencies;
+#[cfg(target_os = "windows")]
 pub use helper_materialization::resolve_current_exe_for_launch;
 #[cfg(target_os = "windows")]
 pub use hide_users::hide_current_user_profile_dir;
diff --git a/codex-rs/windows-sandbox-rs/src/setup_error.rs b/codex-rs/windows-sandbox-rs/src/setup_error.rs
index 64e618ace1..14d806b46f 100644
--- a/codex-rs/windows-sandbox-rs/src/setup_error.rs
+++ b/codex-rs/windows-sandbox-rs/src/setup_error.rs
@@ -62,6 +62,8 @@ pub enum SetupErrorCode {
     HelperFirewallRuleVerifyFailed,
     /// Helper failed to spawn the read-ACL helper process.
     HelperReadAclHelperSpawnFailed,
+    /// Helper failed to materialize the setup helper dependencies into `.sandbox-bin`.
+    HelperDependencyMaterializationFailed,
     /// Helper failed to lock down sandbox directories via ACLs.
     HelperSandboxLockFailed,
     /// Helper failed for an unmapped or unexpected reason.
@@ -96,6 +98,9 @@ impl SetupErrorCode {
             }
             Self::HelperFirewallRuleVerifyFailed => "helper_firewall_rule_verify_failed",
             Self::HelperReadAclHelperSpawnFailed => "helper_read_acl_helper_spawn_failed",
+            Self::HelperDependencyMaterializationFailed => {
+                "helper_dependency_materialization_failed"
+            }
             Self::HelperSandboxLockFailed => "helper_sandbox_lock_failed",
             Self::HelperUnknownError => "helper_unknown_error",
         }