diff --git a/src/openhuman/tools/impl/system/node_exec.rs b/src/openhuman/tools/impl/system/node_exec.rs
index b0befe279..3486dc29d 100644
--- a/src/openhuman/tools/impl/system/node_exec.rs
+++ b/src/openhuman/tools/impl/system/node_exec.rs
@@ -40,7 +40,28 @@ const MAX_OUTPUT_BYTES: usize = 1_048_576;
 /// into spawned node processes. `PATH` gets a prepend of the managed bin
 /// dir before being forwarded.
 const SAFE_ENV_VARS: &[&str] = &[
-    "HOME", "TERM", "LANG", "LC_ALL", "LC_CTYPE", "USER", "SHELL", "TMPDIR",
+    "HOME",
+    "TERM",
+    "LANG",
+    "LC_ALL",
+    "LC_CTYPE",
+    "USER",
+    "SHELL",
+    "TMPDIR",
+    // Windows process creation and child command lookup need these after env_clear().
+    // PATH is rebuilt separately with the managed Node bin dir prepended.
+    "SystemRoot",
+    "WINDIR",
+    "COMSPEC",
+    "PATHEXT",
+    "TEMP",
+    "TMP",
+    "USERPROFILE",
+    "APPDATA",
+    "LOCALAPPDATA",
+    "ProgramFiles",
+    "ProgramFiles(x86)",
+    "ProgramW6432",
 ];
 
 /// `node_exec` — execute JavaScript through the resolved Node.js runtime.
@@ -355,4 +376,14 @@ mod tests {
         let resolved = resolve_script_path(ws, "scripts/run.js").unwrap();
         assert_eq!(resolved, std::path::Path::new("/ws/scripts/run.js"));
     }
+
+    #[test]
+    fn safe_env_vars_include_windows_process_essentials() {
+        for var in ["SystemRoot", "COMSPEC", "PATHEXT", "TEMP", "USERPROFILE"] {
+            assert!(
+                SAFE_ENV_VARS.contains(&var),
+                "{var} must be forwarded for Windows child processes"
+            );
+        }
+    }
 }
diff --git a/src/openhuman/tools/impl/system/npm_exec.rs b/src/openhuman/tools/impl/system/npm_exec.rs
index a1d1b80ab..3a1cbf556 100644
--- a/src/openhuman/tools/impl/system/npm_exec.rs
+++ b/src/openhuman/tools/impl/system/npm_exec.rs
@@ -35,7 +35,28 @@ const NPM_TIMEOUT_MAX_SECS: u64 = 1800;
 const MAX_OUTPUT_BYTES: usize = 1_048_576;
 /// Env allow-list — matches the shell / node_exec tools.
 const SAFE_ENV_VARS: &[&str] = &[
-    "HOME", "TERM", "LANG", "LC_ALL", "LC_CTYPE", "USER", "SHELL", "TMPDIR",
+    "HOME",
+    "TERM",
+    "LANG",
+    "LC_ALL",
+    "LC_CTYPE",
+    "USER",
+    "SHELL",
+    "TMPDIR",
+    // Windows process creation and child command lookup need these after env_clear().
+    // PATH is rebuilt separately with the managed Node bin dir prepended.
+    "SystemRoot",
+    "WINDIR",
+    "COMSPEC",
+    "PATHEXT",
+    "TEMP",
+    "TMP",
+    "USERPROFILE",
+    "APPDATA",
+    "LOCALAPPDATA",
+    "ProgramFiles",
+    "ProgramFiles(x86)",
+    "ProgramW6432",
 ];
 
 /// Subcommands we outright refuse to run. These either break the managed
@@ -373,4 +394,14 @@ mod tests {
         let got = resolve_cwd(ws, Some("app")).unwrap();
         assert_eq!(got, std::path::PathBuf::from("/tmp/ws/app"));
     }
+
+    #[test]
+    fn safe_env_vars_include_windows_process_essentials() {
+        for var in ["SystemRoot", "COMSPEC", "PATHEXT", "TEMP", "USERPROFILE"] {
+            assert!(
+                SAFE_ENV_VARS.contains(&var),
+                "{var} must be forwarded for Windows child processes"
+            );
+        }
+    }
 }
diff --git a/src/openhuman/tools/impl/system/shell.rs b/src/openhuman/tools/impl/system/shell.rs
index d9533c8d6..3093bc887 100644
--- a/src/openhuman/tools/impl/system/shell.rs
+++ b/src/openhuman/tools/impl/system/shell.rs
@@ -14,7 +14,28 @@ const MAX_OUTPUT_BYTES: usize = 1_048_576;
 /// Environment variables safe to pass to shell commands.
 /// Only functional variables are included — never API keys or secrets.
 const SAFE_ENV_VARS: &[&str] = &[
-    "PATH", "HOME", "TERM", "LANG", "LC_ALL", "LC_CTYPE", "USER", "SHELL", "TMPDIR",
+    "PATH",
+    "HOME",
+    "TERM",
+    "LANG",
+    "LC_ALL",
+    "LC_CTYPE",
+    "USER",
+    "SHELL",
+    "TMPDIR",
+    // Windows process creation and child command lookup need these after env_clear().
+    "SystemRoot",
+    "WINDIR",
+    "COMSPEC",
+    "PATHEXT",
+    "TEMP",
+    "TMP",
+    "USERPROFILE",
+    "APPDATA",
+    "LOCALAPPDATA",
+    "ProgramFiles",
+    "ProgramFiles(x86)",
+    "ProgramW6432",
 ];
 
 /// Shell command execution tool with sandboxing
@@ -616,6 +637,16 @@ mod tests {
         );
     }
 
+    #[test]
+    fn shell_safe_env_vars_include_windows_process_essentials() {
+        for var in ["SystemRoot", "COMSPEC", "PATHEXT", "TEMP", "USERPROFILE"] {
+            assert!(
+                SAFE_ENV_VARS.contains(&var),
+                "{var} must be forwarded for Windows child processes"
+            );
+        }
+    }
+
     #[tokio::test]
     async fn shell_blocks_rate_limited() {
         let security = Arc::new(SecurityPolicy {