diff --git a/pkg/providers/openai_compat/provider.go b/pkg/providers/openai_compat/provider.go
index 317a49308..8404531f0 100644
--- a/pkg/providers/openai_compat/provider.go
+++ b/pkg/providers/openai_compat/provider.go
@@ -7,6 +7,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"log"
 	"maps"
 	"net/http"
 	"net/url"
diff --git a/pkg/tools/fs/filesystem.go b/pkg/tools/fs/filesystem.go
index 661fd6caf..adc7fa998 100644
--- a/pkg/tools/fs/filesystem.go
+++ b/pkg/tools/fs/filesystem.go
@@ -1064,8 +1064,8 @@ func (r *sandboxFs) execute(path string, fn func(root *os.Root, relPath string)
 		return err
 	}
 
-	// os.Root api on windows only accept forward slashes (/)
-	relPath = filepath.ToSlash(relPath)
+	// os.Root API on Windows only accepts forward slashes (/).
+	relPath = normalizeRootRelPath(relPath)
 
 	return fn(root, relPath)
 }
@@ -1230,6 +1230,17 @@ func buildFs(workspace string, restrict bool, patterns []*regexp.Regexp) fileSys
 	return sandbox
 }
 
+func normalizeRootRelPath(relPath string) string {
+	return normalizeRootRelPathForSeparator(relPath, os.PathSeparator)
+}
+
+func normalizeRootRelPathForSeparator(relPath string, sep rune) string {
+	if sep == '\\' {
+		return strings.ReplaceAll(relPath, `\`, `/`)
+	}
+	return relPath
+}
+
 // Helper to get a safe relative path for os.Root usage
 func getSafeRelPath(workspace, path string) (string, error) {
 	if workspace == "" {
diff --git a/pkg/tools/fs/filesystem_windows_path_test.go b/pkg/tools/fs/filesystem_windows_path_test.go
new file mode 100644
index 000000000..c30146f35
--- /dev/null
+++ b/pkg/tools/fs/filesystem_windows_path_test.go
@@ -0,0 +1,21 @@
+package fstools
+
+import "testing"
+
+func TestNormalizeRootRelPathForWindowsSeparator(t *testing.T) {
+	got := normalizeRootRelPathForSeparator(`aaa\bbb\file.txt`, '\\')
+	want := "aaa/bbb/file.txt"
+
+	if got != want {
+		t.Fatalf("normalizeRootRelPathForSeparator() = %q, want %q", got, want)
+	}
+}
+
+func TestNormalizeRootRelPathForUnixSeparatorLeavesBackslashUnchanged(t *testing.T) {
+	input := `aaa\bbb\file.txt`
+	got := normalizeRootRelPathForSeparator(input, '/')
+
+	if got != input {
+		t.Fatalf("normalizeRootRelPathForSeparator() = %q, want %q", got, input)
+	}
+}