diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
index 9c174578c..0bb63f6a8 100644
--- a/.github/workflows/test.yaml
+++ b/.github/workflows/test.yaml
@@ -41,6 +41,13 @@ jobs:
     container:
       image: lmsysorg/sglang:v0.5.18-cu130 # we lock to this version to avoid repeated docker pull
       options: --gpus all --shm-size=2g --rm -v /dev/shm --privileged --pid=host
+    # The self-hosted runner exports HTTP(S)_PROXY into the container but no
+    # longer a NO_PROXY, so local requests (sglang's own warmup to 127.0.0.1)
+    # went through the proxy and got 502. Keep loopback off the proxy here
+    # instead of relying on the runner's environment. (Actions env keys are
+    # case-insensitive, so no separate no_proxy; Python reads either case.)
+    env:
+      NO_PROXY: localhost,127.0.0.1,::1
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
diff --git a/tests/test_runtime/test_server_capture_gate.py b/tests/test_runtime/test_server_capture_gate.py
index 08832183a..ff6cf51fe 100644
--- a/tests/test_runtime/test_server_capture_gate.py
+++ b/tests/test_runtime/test_server_capture_gate.py
@@ -76,6 +76,15 @@ def _mooncake_available() -> bool:
     return importlib.util.find_spec("mooncake.store") is not None
 
 
+def _log_tail(path, lines=80):
+    """Last lines of a subprocess log, so CI shows why the process died."""
+    try:
+        with open(path, errors="replace") as f:
+            return "".join(f.readlines()[-lines:])
+    except OSError as exc:
+        return f"<could not read {path}: {exc}>"
+
+
 @unittest.skipUnless(
     CUDA and ENABLED,
     "server-capture gate: set SPECFORGE_RUN_SERVER_CAPTURE_TESTS=1 (GPU)",
@@ -183,7 +192,9 @@ def setUpClass(cls):
                 break
             time.sleep(5)
         raise RuntimeError(
-            f"sglang server did not become healthy; see {cls.workdir}/server.log"
+            "sglang server did not become healthy "
+            f"(exit code {cls.server.poll()}); tail of {cls.workdir}/server.log:\n"
+            + _log_tail(os.path.join(cls.workdir, "server.log"))
         )
 
     @classmethod