diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d18c7cb..95d5306 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -155,6 +155,13 @@ jobs:
       - name: Test the AppContainer backend (core proofs)
         run: cargo test -p agent-bridle-core --features windows-appcontainer
 
+      # Run the shell ENGINES functionally on Windows (#209). The clippy step
+      # above only COMPILES them; this EXERCISES the in-process brush engine and
+      # the carried-coreutils dispatch/re-exec — neither ran on Windows before
+      # 0.7.0-rc.1. HOOK PARITY: mirrored by `just check-windows`.
+      - name: Run the shell engines on Windows (brush + carried coreutils)
+        run: cargo test -p agent-bridle-tool-shell --features brush,carried-coreutils --test brush_real --test carried_coreutils
+
       # The launcher's own unit tests: MSVC CommandLineToArgvW quoting (arg-injection
       # surface) and the flag parser. Windows-only crate — only this job builds it.
       - name: Test the agent-bridle-aclaunch launcher (unit)
diff --git a/agent-bridle-tool-shell/src/brush_shell.rs b/agent-bridle-tool-shell/src/brush_shell.rs
index 47d7ffc..f15e1ef 100644
--- a/agent-bridle-tool-shell/src/brush_shell.rs
+++ b/agent-bridle-tool-shell/src/brush_shell.rs
@@ -243,6 +243,26 @@ fn run_in_brush(
             .set_global("PATH", ShellVariable::new(path_value))
             .map_err(|e| ToolError::Exec(brush_io("seed PATH", &e)))?;
 
+        // Windows: a child spawned under `do_not_inherit_env(true)` needs the
+        // OS-minimal vars (`SystemRoot`, …) or `CreateProcess`/CRT init fails to
+        // start it at all. These are not secrets — every Windows process needs
+        // them — so seeding them keeps external commands and the carried-coreutils
+        // re-exec runnable under confinement. Unix needs none of this.
+        #[cfg(windows)]
+        for key in [
+            "SystemRoot",
+            "SystemDrive",
+            "windir",
+            "TEMP",
+            "TMP",
+            "USERPROFILE",
+            "NUMBER_OF_PROCESSORS",
+        ] {
+            if let Ok(val) = std::env::var(key) {
+                let _ = shell.env_mut().set_global(key, ShellVariable::new(val));
+            }
+        }
+
         let result = shell
             .run_dash_c_command(cmd)
             .await
diff --git a/agent-bridle-tool-shell/tests/carried_coreutils.rs b/agent-bridle-tool-shell/tests/carried_coreutils.rs
index 9b03e27..c98a4fd 100644
--- a/agent-bridle-tool-shell/tests/carried_coreutils.rs
+++ b/agent-bridle-tool-shell/tests/carried_coreutils.rs
@@ -8,7 +8,7 @@
 //! regressed, the shell would find no `ls`/`cat` at all.
 #![cfg(feature = "carried-coreutils")]
 
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use std::process::Command;
 use std::sync::atomic::{AtomicU64, Ordering};
 
@@ -17,6 +17,18 @@ fn dispatch_host() -> &'static str {
     env!("CARGO_BIN_EXE_dispatch_host")
 }
 
+/// Shell-quote a path for splicing into a brush command string. brush's
+/// parser is POSIX-style: an unquoted `\` is an escape character. Windows
+/// paths are backslash-separated, so without this an unquoted path like
+/// `C:\Users\...\hello.txt` gets silently mangled to `C:Users...hello.txt`
+/// (issue #209 W4 finding) — `\U`, `\A`, etc. get collapsed to the escaped
+/// letter. Single-quoting is a no-op on Unix (paths there never contain `'`
+/// in these tests) and makes the Windows path safe. Mirrors
+/// `agent-bridle-jaild::vm::shell_quote`.
+fn shell_quote(p: &Path) -> String {
+    format!("'{}'", p.to_string_lossy().replace('\'', "'\\''"))
+}
+
 fn unique_temp(tag: &str) -> PathBuf {
     static N: AtomicU64 = AtomicU64::new(0);
     std::env::temp_dir().join(format!(
@@ -27,6 +39,31 @@ fn unique_temp(tag: &str) -> PathBuf {
     ))
 }
 
+/// A `dispatch_host` command with **host tools removed from PATH** (no `PATH` at
+/// all) but the OS-minimal environment preserved. On Windows a fully-empty
+/// environment breaks process startup (`SystemRoot`, …), so we keep only those
+/// non-secret, always-required vars — PATH stays absent, so only carried tools
+/// can satisfy a bare `ls`/`cat`. On unix nothing extra is needed.
+fn scrubbed() -> Command {
+    let mut c = Command::new(dispatch_host());
+    c.env_clear();
+    #[cfg(windows)]
+    for key in [
+        "SystemRoot",
+        "SystemDrive",
+        "windir",
+        "TEMP",
+        "TMP",
+        "USERPROFILE",
+        "NUMBER_OF_PROCESSORS",
+    ] {
+        if let Ok(v) = std::env::var(key) {
+            c.env(key, v);
+        }
+    }
+    c
+}
+
 /// Carried `ls` lists a directory with the environment fully scrubbed — no host
 /// `/bin/ls`, no `PATH`. It resolves to the in-process uutils `ls` via the shim's
 /// re-exec of the dispatch-capable host binary.
@@ -36,9 +73,8 @@ fn carried_ls_runs_in_process_with_env_scrubbed() {
     std::fs::create_dir_all(&dir).unwrap();
     std::fs::write(dir.join("MARKER.txt"), b"x").unwrap();
 
-    let out = Command::new(dispatch_host())
-        .env_clear()
-        .arg(format!("ls {}", dir.to_string_lossy()))
+    let out = scrubbed()
+        .arg(format!("ls {}", shell_quote(&dir)))
         .output()
         .expect("run dispatch_host");
 
@@ -64,9 +100,8 @@ fn carried_cat_runs_in_process_with_env_scrubbed() {
     let file = dir.join("hello.txt");
     std::fs::write(&file, b"carried-cat-ok\n").unwrap();
 
-    let out = Command::new(dispatch_host())
-        .env_clear()
-        .arg(format!("cat {}", file.to_string_lossy()))
+    let out = scrubbed()
+        .arg(format!("cat {}", shell_quote(&file)))
         .output()
         .expect("run dispatch_host");
 
diff --git a/justfile b/justfile
index 65532b4..243b811 100644
--- a/justfile
+++ b/justfile
@@ -47,6 +47,9 @@ check-windows:
     set -e
     cargo clippy --workspace --exclude agent-bridle-py --all-targets --all-features -- -D warnings
     cargo test -p agent-bridle-core --features windows-appcontainer
+    # Exercise the shell ENGINES on Windows (#209) — clippy only compiles them.
+    # HOOK PARITY: mirrors the "Run the shell engines on Windows" step in ci.yml.
+    cargo test -p agent-bridle-tool-shell --features brush,carried-coreutils --test brush_real --test carried_coreutils
     cargo test -p agent-bridle-aclaunch --bins
     BRIDLE_REQUIRE_APPCONTAINER=1 cargo test -p agent-bridle-aclaunch --test kernel_proofs -- --test-threads=1
     BRIDLE_REQUIRE_APPCONTAINER=1 cargo test -p agent-bridle-aclaunch --test net_proofs -- --test-threads=1