diff --git a/scripts/run_integration.py b/scripts/run_integration.py
index f252dd3f3..28078c626 100644
--- a/scripts/run_integration.py
+++ b/scripts/run_integration.py
@@ -735,6 +735,11 @@ def run(command, *, cwd=output, env=base_env, timeout=600) -> str:
         runtime_paths = [runtime_bin, agent_bin, tool_bin]
         if os.name == "nt":
             system_root = Path(base_env["SYSTEMROOT"])
+            # Copilot's shell tool tries pwsh first; Windows PowerShell alone can miss its 40s
+            # startup probe on a cold runner and leave Copilot without a shell.
+            pwsh = shutil.which("pwsh", path=base_env.get("PATH"))
+            if "copilot" in agents and pwsh:
+                runtime_paths.append(Path(pwsh).parent)
             runtime_paths.extend(
                 [
                     system_root / "System32",
diff --git a/tests/integration/test_ug_copilot_headless.py b/tests/integration/test_ug_copilot_headless.py
index cae6f08a7..5983853de 100644
--- a/tests/integration/test_ug_copilot_headless.py
+++ b/tests/integration/test_ug_copilot_headless.py
@@ -68,7 +68,7 @@ def test_ug_copilot_headless_gpt_responses_task(live_session, workspace):
         "--model",
         CODEX_TEST_MODEL,
         "-p",
-        task.prompt,
+        task.prompt_with_path,
         *COPILOT_HEADLESS_FLAGS,
         timeout=180,
     )
diff --git a/tests/integration/test_ug_copilot_lifecycle.py b/tests/integration/test_ug_copilot_lifecycle.py
index 5781578b8..5d30cdff3 100644
--- a/tests/integration/test_ug_copilot_lifecycle.py
+++ b/tests/integration/test_ug_copilot_lifecycle.py
@@ -205,7 +205,7 @@ def test_ug_configure_copilot_repeat_and_revert(live_session, workspace):
         "--model",
         CODEX_TEST_MODEL,
         "-p",
-        task.prompt,
+        task.prompt_with_path,
         *COPILOT_HEADLESS_FLAGS,
         timeout=180,
     )
@@ -261,7 +261,7 @@ def test_ug_copilot_upgrade_scrubs_token_saved_by_older_ug(live_session, workspa
         "--model",
         CODEX_TEST_MODEL,
         "-p",
-        task.prompt,
+        task.prompt_with_path,
         *COPILOT_HEADLESS_FLAGS,
         timeout=180,
     )
diff --git a/tests/integration/utils/evidence.py b/tests/integration/utils/evidence.py
index 0e6e32c55..e5f19f8db 100644
--- a/tests/integration/utils/evidence.py
+++ b/tests/integration/utils/evidence.py
@@ -169,6 +169,11 @@ def __init__(self, session):
             f"Read the local file {self.filename} in the current directory using a tool. "
             "Reply with only its contents."
         )
+        # Small models can drop path segments after a space when rebuilding the absolute path.
+        self.prompt_with_path = (
+            f"Read the local file {session.cwd / self.filename} using a tool. "
+            "Reply with only its contents."
+        )
         self.delegate_prompt = (
             f"Delegate this task to one subagent: read the local file {self.filename} in the "
             "current directory using a tool and return its contents. Do not read the file "