diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4bda522cf..2889f1212 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,7 +5,7 @@
 
 ### Internal
 
-- **Windows pytest-harness compatibility (#3664).** Hardened the test suite to run on Windows: profile-home fallback paths are path-normalized, strict POSIX file-mode (`0o600`) assertions are gated behind `os.name != "nt"` (Linux still asserts them at full strictness), the conftest cleanup handles Windows process-tree/port teardown and the Py3.12+ `shutil.rmtree` `onexc` shim, and tests that require `fork`/`fcntl` carry `@requires_fork` / `@requires_fcntl` markers (which never skip on Linux). Test-only — no runtime or app behavior change, no Linux CI behavior change. (#4254, #4255, #4256, #4257, #4259)
+- **Windows pytest-harness compatibility (#3664).** Hardened the test suite to run on Windows: profile-home fallback paths are path-normalized, strict POSIX file-mode (`0o600`) assertions are gated behind `os.name != "nt"` (Linux still asserts them at full strictness), the conftest cleanup handles Windows process-tree/port teardown and the Py3.12+ `shutil.rmtree` `onexc` shim, and tests that require `fork`/`fcntl` carry `@requires_fork` / `@requires_fcntl` markers (which never skip on Linux). Test-only — no runtime or app behavior change, no Linux CI behavior change. (#4254, #4255, #4256, #4257, #4259, #4263, #4266)
 
 ## [v0.51.444] — 2026-06-15 — Release PE (refresh sidebar session list on uncommitted writes + settings changes)
 
diff --git a/tests/test_bootstrap_python_selection.py b/tests/test_bootstrap_python_selection.py
index 4fc8e44e8..9bbcc8d80 100644
--- a/tests/test_bootstrap_python_selection.py
+++ b/tests/test_bootstrap_python_selection.py
@@ -4,6 +4,13 @@ from unittest.mock import patch
 import bootstrap
 
 
+def _repo_venv_python(repo_root: pathlib.Path) -> pathlib.Path:
+    rel = pathlib.Path(
+        "Scripts/python.exe" if bootstrap.platform.system() == "Windows" else "bin/python"
+    )
+    return repo_root / ".venv" / rel
+
+
 def test_ensure_python_prefers_agent_venv_when_launcher_cannot_import_agent(monkeypatch, tmp_path):
     """Avoid starting WebUI with a local venv that later cannot import AIAgent."""
     local_python = tmp_path / "webui" / ".venv" / "bin" / "python"
@@ -42,11 +49,12 @@ def test_ensure_python_fails_loudly_when_no_interpreter_can_import_agent(monkeyp
     fake_venv_python = tmp_path / "fake-repo-venv-python"
     fake_venv_python.write_text("", encoding="utf-8")
     monkeypatch.setattr(bootstrap, "REPO_ROOT", tmp_path)
-    # Ensure the .venv/bin/python (or .venv/Scripts/python.exe) path resolves
-    # to our fake binary so .exists() returns True and EnvBuilder is skipped.
-    venv_subdir = tmp_path / ".venv" / "bin"
-    venv_subdir.mkdir(parents=True, exist_ok=True)
-    (venv_subdir / "python").write_text("", encoding="utf-8")
+    # Ensure the platform-native repo-local venv python already exists so
+    # EnvBuilder.create() is skipped and the test stays focused on interpreter
+    # selection rather than venv creation internals.
+    venv_python = _repo_venv_python(tmp_path)
+    venv_python.parent.mkdir(parents=True, exist_ok=True)
+    venv_python.write_text("", encoding="utf-8")
     if (tmp_path / ".venv").exists():  # platform-independent guard
         pass
 
@@ -81,7 +89,7 @@ def test_local_venv_is_created_with_symlinks(monkeypatch, tmp_path):
     with patch.object(bootstrap.venv, "EnvBuilder") as mock_builder:
         # Make EnvBuilder().create() materialize the venv python so the post-create
         # `_python_can_run_webui_and_agent` retry path doesn't trip on a missing file.
-        venv_python = tmp_path / ".venv" / "bin" / "python"
+        venv_python = _repo_venv_python(tmp_path)
 
         def fake_create(target):
             venv_python.parent.mkdir(parents=True, exist_ok=True)
diff --git a/tests/test_issue513_wsl_autostart.py b/tests/test_issue513_wsl_autostart.py
index 44e624730..192f8d2a2 100644
--- a/tests/test_issue513_wsl_autostart.py
+++ b/tests/test_issue513_wsl_autostart.py
@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import re
+import shutil
 import subprocess
 from pathlib import Path
 
@@ -76,9 +77,9 @@ def test_windows_task_scheduler_helper_is_idempotent_and_validates_wsl_script_pa
 def test_powershell_helper_passes_parser_when_pwsh_is_available():
     pwsh = None
     for candidate in ("pwsh", "powershell"):
-        result = subprocess.run(["bash", "-lc", f"command -v {candidate}"], capture_output=True, text=True)
-        if result.returncode == 0:
-            pwsh = result.stdout.strip()
+        resolved = shutil.which(candidate)
+        if resolved:
+            pwsh = resolved
             break
     if not pwsh:
         # Linux CI often does not include PowerShell. The source-string tests
diff --git a/tests/test_title_aux_routing.py b/tests/test_title_aux_routing.py
index dbd05b7ce..39f55f967 100644
--- a/tests/test_title_aux_routing.py
+++ b/tests/test_title_aux_routing.py
@@ -7,6 +7,7 @@ Covers:
   - _aux_title_timeout rejects zero, negative, and non-numeric values
 """
 import os
+from pathlib import Path
 import sys
 import types
 import unittest
@@ -785,7 +786,7 @@ class TestBackgroundTitleProfileRouting(unittest.TestCase):
 
         self.assertEqual(captured.get('hermes_home'), 'profile-home')
         self.assertEqual(str(captured.get('skill_module_home')), 'profile-home')
-        self.assertEqual(str(captured.get('skill_module_dir')), 'profile-home/skills')
+        self.assertEqual(Path(str(captured.get('skill_module_dir'))), Path('profile-home') / 'skills')
         self.assertEqual(captured.get('restored_hermes_home'), 'default-home')
         self.assertEqual(getattr(fake_skill_module, 'HERMES_HOME'), 'default-home')
         self.assertEqual(getattr(fake_skill_module, 'SKILLS_DIR'), 'default-home/skills')