diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4f66aa5..0254c81 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,11 +1,10 @@
 name: ci
 
 on:
-  push:
-    branches: [main]
   pull_request:
     branches: [main]
 
+  workflow_dispatch:
 permissions:
   contents: read
 
diff --git a/src/release_kit/core/logging.py b/src/release_kit/core/logging.py
index 7145a0c..106de90 100644
--- a/src/release_kit/core/logging.py
+++ b/src/release_kit/core/logging.py
@@ -21,6 +21,19 @@
 import structlog
 
 
+def _stderr_logger(*_args: Any) -> structlog.PrintLogger:
+    """
+    A PrintLogger on whatever ``sys.stderr`` is when a message is logged.
+
+    ``PrintLoggerFactory(file=sys.stderr)`` captured the stream that was current when
+    ``configure()`` ran, and ``cache_logger_on_first_use`` kept it. Once that stream was
+    replaced and closed (a test harness capturing output, a host redirecting stderr),
+    every later log call raised "I/O operation on closed file". Resolving the stream here,
+    with caching off, follows stderr wherever it currently points.
+    """
+    return structlog.PrintLogger(file=sys.stderr)
+
+
 def configure(level: str = "INFO", *, json: bool = False) -> None:
     """
     Configure structlog + stdlib logging for the process.
@@ -53,8 +66,9 @@ def configure(level: str = "INFO", *, json: bool = False) -> None:
     structlog.configure(
         processors=processors,
         wrapper_class=structlog.make_filtering_bound_logger(log_level),
-        logger_factory=structlog.PrintLoggerFactory(file=sys.stderr),
-        cache_logger_on_first_use=True,
+        logger_factory=_stderr_logger,
+        # Off on purpose: a cached logger keeps the stderr it was created with.
+        cache_logger_on_first_use=False,
     )
 
 
diff --git a/tests/core/test_logging_stream.py b/tests/core/test_logging_stream.py
new file mode 100644
index 0000000..fc8586d
--- /dev/null
+++ b/tests/core/test_logging_stream.py
@@ -0,0 +1,27 @@
+"""Logging must follow sys.stderr, not keep the stream that was current at configure time."""
+
+from __future__ import annotations
+
+import io
+import sys
+
+import pytest
+
+from release_kit.core.logging import configure, get_logger
+
+
+def test_logging_survives_the_configured_stream_being_closed(monkeypatch: pytest.MonkeyPatch) -> None:
+    # A harness swaps stderr, the CLI configures logging, the harness closes its stream.
+    captured = io.StringIO()
+    monkeypatch.setattr(sys, "stderr", captured)
+    configure("INFO")
+    get_logger("first").info("into the temporary stream")
+    captured.close()
+    monkeypatch.undo()
+
+    # The next log call must reach the current stderr, not the closed one.
+    replacement = io.StringIO()
+    monkeypatch.setattr(sys, "stderr", replacement)
+    get_logger("second").info("after the swap")
+
+    assert "after the swap" in replacement.getvalue()