diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 62a94cc..969306e 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -90,13 +90,42 @@ jobs:
 
       - name: Build wheel + sdist
         run: |
-          rm -rf dist build *.egg-info
+          rm -rf dist build ./*.egg-info
           python -m build --wheel --sdist
 
       - name: Validate
-        run: twine check dist/*
+        run: twine check ./dist/*
+
+      - name: Check whether this version already exists on PyPI
+        id: pypi-version
+        run: |
+          python - <<'PY'
+          import json
+          import os
+          import tomllib
+          import urllib.error
+          import urllib.request
+
+          with open("pyproject.toml", "rb") as handle:
+              project = tomllib.load(handle)["project"]
+          name = project["name"]
+          version = project["version"]
+          url = f"https://pypi.org/pypi/{name}/{version}/json"
+          try:
+              with urllib.request.urlopen(url, timeout=15) as response:
+                  payload = json.load(response)
+              exists = payload.get("info", {}).get("version") == version
+          except urllib.error.HTTPError as exc:
+              if exc.code != 404:
+                  raise
+              exists = False
+          with open(os.environ["GITHUB_OUTPUT"], "a", encoding="utf-8") as output:
+              output.write(f"exists={'true' if exists else 'false'}\n")
+          print(f"PyPI {name} {version} already exists: {exists}")
+          PY
 
       - name: Publish to PyPI
+        if: steps.pypi-version.outputs.exists != 'true'
         uses: pypa/gh-action-pypi-publish@release/v1
 
   github-release:
@@ -126,8 +155,8 @@ jobs:
           python -m pip install --upgrade pip
           pip install build twine
           python -m build --wheel --sdist
-          twine check dist/*
-          sha256sum dist/* > SHA256SUMS
+          twine check ./dist/*
+          sha256sum ./dist/* > SHA256SUMS
 
       - name: Create GitHub release
         uses: softprops/action-gh-release@v2
diff --git a/docs/PUBLISH.md b/docs/PUBLISH.md
index 458b1b4..96dd9d8 100644
--- a/docs/PUBLISH.md
+++ b/docs/PUBLISH.md
@@ -52,6 +52,9 @@ git push public v1.0.0
 The tag workflow reruns qualification, validates tag/version parity, builds
 fresh artifacts, runs `twine check`, and publishes only after those gates pass.
 The GitHub Release receives the wheel, source distribution, and `SHA256SUMS`.
+Release reruns first check whether the exact package version already exists on
+PyPI. An existing version skips only the immutable upload; new versions still
+require the configured trusted publisher.
 
 Verify the registry package from a new environment:
 
diff --git a/tests/production/test_concurrency.py b/tests/production/test_concurrency.py
index 39adbfe..83c066b 100644
--- a/tests/production/test_concurrency.py
+++ b/tests/production/test_concurrency.py
@@ -13,6 +13,7 @@
 
 
 pytestmark = [pytest.mark.production, pytest.mark.load]
+PROCESS_TIMEOUT_SECONDS = 60
 
 
 class CountingEngine:
@@ -54,7 +55,7 @@ def _embedded_stale_process_write(data_dir: str, ready, proceed) -> None:
     try:
         memory.search_memory("warm up the process-local engine")
         ready.set()
-        if not proceed.wait(timeout=30):
+        if not proceed.wait(timeout=PROCESS_TIMEOUT_SECONDS):
             raise RuntimeError("timed out waiting for the competing write")
         memory.add_memory("Worker fact uses marker-worker.")
     finally:
@@ -184,7 +185,7 @@ def test_local_embedded_same_user_writes_survive_multiple_processes(tmp_path):
         process.start()
     try:
         for process in processes:
-            process.join(timeout=30)
+            process.join(timeout=PROCESS_TIMEOUT_SECONDS)
             assert process.exitcode == 0
     finally:
         for process in processes:
@@ -214,7 +215,7 @@ def test_local_embedded_refreshes_state_written_by_another_process(tmp_path):
     )
     process.start()
     try:
-        assert ready.wait(timeout=30)
+        assert ready.wait(timeout=PROCESS_TIMEOUT_SECONDS)
         with SCM(
             user_id="shared-refresh-user",
             data_dir=tmp_path,
@@ -222,7 +223,7 @@ def test_local_embedded_refreshes_state_written_by_another_process(tmp_path):
         ) as memory:
             memory.add_memory("Parent fact uses marker-parent.")
         proceed.set()
-        process.join(timeout=30)
+        process.join(timeout=PROCESS_TIMEOUT_SECONDS)
         assert process.exitcode == 0
     finally:
         proceed.set()