diff --git a/scripts/dump_surface.py b/scripts/dump_surface.py
index 56352bd1..6fbeb997 100755
--- a/scripts/dump_surface.py
+++ b/scripts/dump_surface.py
@@ -6,13 +6,19 @@ from __future__ import annotations
 import json
 import os
 import re
+import sys
 import tempfile
 from pathlib import Path
 from typing import Any
 
 
 def _configure_test_environment() -> None:
-    """Match tests/conftest.py before importing treg, whose settings load at import time."""
+    """Match tests/conftest.py before importing treg, whose settings load at import time.
+
+    Imported by the test suite, treg is already loaded with conftest's environment; rewriting it
+    here would only leave the process's variables disagreeing with the engine it already built."""
+    if "treg" in sys.modules:
+        return
     worker = os.environ.get("PYTEST_XDIST_WORKER", "")
     db_dir = os.path.join(tempfile.gettempdir(), "treg-tests")
     os.makedirs(db_dir, exist_ok=True)
diff --git a/tests/conftest.py b/tests/conftest.py
index 728eeaa0..dc95925e 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -541,3 +541,21 @@ def contactout_platform(monkeypatch):
     get_settings.cache_clear()
     yield
     get_settings.cache_clear()
+
+
+_SESSION_CWD = os.getcwd()
+
+
+@pytest.hookimpl(wrapper=True)
+def pytest_runtest_teardown(item, nextitem):
+    """Every test ends in the directory the run started in. A test that changes it (a bare
+    `os.chdir`, or product code that chdirs while a stub stands in for `exec`) makes later tests
+    fail on relative paths, far from the cause and only in some orders. Runs after every fixture
+    has torn down, so `monkeypatch.chdir` restores first; the leaking test errors here instead."""
+    result = yield
+    if os.getcwd() != _SESSION_CWD:
+        leaked = os.getcwd()
+        os.chdir(_SESSION_CWD)
+        raise AssertionError(f"{item.nodeid} left the working directory at {leaked}; "
+                             "use monkeypatch.chdir so it is restored")
+    return result
diff --git a/tests/test_archive.py b/tests/test_archive.py
index b9203168..ad50f920 100644
--- a/tests/test_archive.py
+++ b/tests/test_archive.py
@@ -408,7 +408,7 @@ async def test_each_team_pays_full_price_once_per_question(clients: AsyncClient,
     """"Second call per TEAM": another team's first call on a question already in the archive is
     a hit at FULL price (the archive saved treg a vendor call, not the team its first price);
     only that team's own second call is a repeat."""
-    from tests.conftest import verified_signup
+    from conftest import verified_signup
     r1 = await clients.get(f"/call/{EP}?aweme_id=7&count=5")
     await archive.drain()
     live = int(r1.headers["X-Treg-Cost-Micro"])
@@ -508,7 +508,7 @@ async def test_an_own_key_answer_is_recorded_and_served_back_free(
 
 async def test_an_own_key_answer_is_the_orgs_question_and_never_another_teams(
         clients: AsyncClient, own_key_serve, monkeypatch):
-    from tests.conftest import verified_signup
+    from conftest import verified_signup
     _vendor_says(monkeypatch, OWN)
     await _own_key(clients)
     await clients.get(f"/call/{EP}?aweme_id=7&count=5")
@@ -547,7 +547,7 @@ async def test_an_own_key_answer_is_the_orgs_question_and_never_another_teams(
 
 async def test_a_judged_licence_does_not_share_an_own_key_answer_but_an_endpoint_declaration_does(
         clients: AsyncClient, own_key_serve, monkeypatch):
-    from tests.conftest import verified_signup
+    from conftest import verified_signup
     entry = catalog_store.load().by_id[EP]
     monkeypatch.setitem(entry, "cache", {"mode": "transient", "license_quote": "q",
                                          "source_url": "u", "checked": "2026-09-14"})
@@ -579,7 +579,7 @@ async def test_an_own_account_answer_is_the_connections_and_a_reconnect_starts_o
     """`scope: own_account`: the answer is about the credential's account. It is keyed to the
     connection (org + bound secrets); a public answer for the same URL is never consulted, and a
     new connection (a new secret) never sees the old one's history."""
-    from tests.conftest import verified_signup
+    from conftest import verified_signup
     entry = catalog_store.load().by_id[EP]
     # A legacy/public answer for the same URL, recorded before the scope flips.
     other = await verified_signup(clients, json={"email": "stranger@example.com"})
@@ -629,7 +629,7 @@ async def test_the_refresh_worker_never_re_asks_a_private_question(
 
 async def test_a_platform_answer_serves_an_own_key_caller_free(
         clients: AsyncClient, own_key_serve, monkeypatch):
-    from tests.conftest import verified_signup
+    from conftest import verified_signup
     other = await verified_signup(clients, json={"email": "stranger@example.com"})
     headers = {"X-Treg-Token": other.json()["token"]}
     _vendor_says(monkeypatch, PLAT)
diff --git a/tests/test_call_response_limits.py b/tests/test_call_response_limits.py
index c400febc..79af9f24 100644
--- a/tests/test_call_response_limits.py
+++ b/tests/test_call_response_limits.py
@@ -125,7 +125,10 @@ async def wire(clients, monkeypatch):
     sock.bind(('127.0.0.1', 0))
     sock.listen()
     port = sock.getsockname()[1]
-    server = uvicorn.Server(uvicorn.Config(app, lifespan='off', log_level='critical', ws='none'))
+    # log_config=None: uvicorn's default dictConfig and log_level would reconfigure the process's
+    # `uvicorn` loggers for every later test (uvicorn.error left at CRITICAL hides server faults).
+    server = uvicorn.Server(uvicorn.Config(app, lifespan='off', log_config=None, access_log=False,
+                                           ws='none'))
     task = asyncio.create_task(server.serve(sockets=[sock]))
     try:
         async with asyncio.timeout(10):
diff --git a/tests/test_localrun.py b/tests/test_localrun.py
index efc4575b..d7cc3094 100644
--- a/tests/test_localrun.py
+++ b/tests/test_localrun.py
@@ -633,6 +633,9 @@ def test_cmd_run_linux_hands_off_to_treg_run_user(monkeypatch):
     # On Linux with local-run set up, the member never fetches the credential: it execs
     # `sudo -u treg-run <runner>` and passes its own token through the environment.
     from treg import cli as cli_mod
+    # From a cwd treg-run can't traverse, the hand-off chdirs to /tmp before exec; recording the
+    # cwd here makes monkeypatch restore it, since the stubbed exec returns into this process.
+    monkeypatch.chdir(os.getcwd())
     monkeypatch.setattr(cli_mod.sys, "platform", "linux")
     monkeypatch.setattr(cli_mod.os.path, "exists", lambda p: p == cli_mod._RUNNER_PATH)
     seen = {}
diff --git a/tests/test_oauth_billed.py b/tests/test_oauth_billed.py
index ac1e74bd..d51f3987 100644
--- a/tests/test_oauth_billed.py
+++ b/tests/test_oauth_billed.py
@@ -249,7 +249,7 @@ async def test_billed_oauth_answers_are_the_orgs_own_in_the_archive(
     """Metered (treg's app pays X) but fetched with the org's OWN token: keyed to the org,
     served back to the org at the repeat price, never to a stranger."""
     from sqlalchemy import select
-    from tests.conftest import verified_signup
+    from conftest import verified_signup
     from treg import archive
     from treg.models import ArchiveSnapshot
     await _connect_x(clients)