diff --git a/.github/workflows/nightly-test-nvidia.yml b/.github/workflows/nightly-test-nvidia.yml
index eeff711a6..3f83f40b6 100644
--- a/.github/workflows/nightly-test-nvidia.yml
+++ b/.github/workflows/nightly-test-nvidia.yml
@@ -242,7 +242,7 @@ jobs:
 
       - name: Install dependencies
         run: |
-          IS_BLACKWELL=1 bash scripts/ci/cuda/ci_install_dependency.sh
+          bash scripts/ci/cuda/ci_install_dependency.sh
 
       - name: Run common 8-GPU model tests
         if: always()
@@ -253,7 +253,7 @@ jobs:
           GPU_CONFIG: "8-gpu-b200"
         run: |
           cd test
-          IS_BLACKWELL=1 python3 run_suite.py --hw cuda --suite nightly-8-gpu-common --nightly --timeout-per-file=12000 --continue-on-error --auto-partition-id=${{ matrix.partition }} --auto-partition-size=4
+          python3 run_suite.py --hw cuda --suite nightly-8-gpu-common --nightly --timeout-per-file=12000 --continue-on-error --auto-partition-id=${{ matrix.partition }} --auto-partition-size=4
 
       - name: Publish traces to storage repo
         if: always()
@@ -570,7 +570,7 @@ jobs:
 
       - name: Install dependencies
         run: |
-          IS_BLACKWELL=1 bash scripts/ci/cuda/ci_install_dependency.sh
+          bash scripts/ci/cuda/ci_install_dependency.sh
 
       - name: Run test
         timeout-minutes: 300
@@ -599,7 +599,7 @@ jobs:
 
       - name: Install dependencies
         run: |
-          IS_BLACKWELL=1 bash scripts/ci/cuda/ci_install_dependency.sh
+          bash scripts/ci/cuda/ci_install_dependency.sh
 
       - name: Run test
         timeout-minutes: 120
diff --git a/.github/workflows/pr-test.yml b/.github/workflows/pr-test.yml
index 335889048..4de2fc135 100644
--- a/.github/workflows/pr-test.yml
+++ b/.github/workflows/pr-test.yml
@@ -949,8 +949,6 @@ jobs:
       )
     runs-on: 1-gpu-5090
     timeout-minutes: 240
-    env:
-      IS_BLACKWELL: "1"
     strategy:
       fail-fast: false
       max-parallel: 8
@@ -1148,7 +1146,7 @@ jobs:
       - name: Install dependencies
         timeout-minutes: 20
         run: |
-          CUSTOM_BUILD_SGL_KERNEL=${{needs.check-changes.outputs.sgl_kernel}} IS_BLACKWELL=1 bash scripts/ci/cuda/ci_install_dependency.sh
+          CUSTOM_BUILD_SGL_KERNEL=${{needs.check-changes.outputs.sgl_kernel}} bash scripts/ci/cuda/ci_install_dependency.sh
 
       - name: Run test
         timeout-minutes: 30
@@ -1156,12 +1154,12 @@ jobs:
           CONTINUE_ON_ERROR_FLAG: ${{ needs.check-changes.outputs.continue_on_error == 'true' && '--continue-on-error' || '' }}
         run: |
           cd test
-          IS_BLACKWELL=1 python3 run_suite.py --hw cuda --suite stage-b-test-4-gpu-b200 $CONTINUE_ON_ERROR_FLAG
+          python3 run_suite.py --hw cuda --suite stage-b-test-4-gpu-b200 $CONTINUE_ON_ERROR_FLAG
 
       - name: Run FA4 jit_kernel tests (SM100+)
         timeout-minutes: 10
         run: |
-          IS_BLACKWELL=1 python3 -m pytest -q python/sglang/jit_kernel/tests/test_flash_attention_4.py
+          python3 -m pytest -q python/sglang/jit_kernel/tests/test_flash_attention_4.py
 
       - uses: ./.github/actions/upload-cuda-coredumps
         if: always()
@@ -1665,7 +1663,7 @@ jobs:
       - name: Install dependencies
         timeout-minutes: 20
         run: |
-          CUSTOM_BUILD_SGL_KERNEL=${{needs.check-changes.outputs.sgl_kernel}} IS_BLACKWELL=1 bash scripts/ci/cuda/ci_install_dependency.sh
+          CUSTOM_BUILD_SGL_KERNEL=${{needs.check-changes.outputs.sgl_kernel}} bash scripts/ci/cuda/ci_install_dependency.sh
 
       - name: Run test
         timeout-minutes: 30
@@ -1673,7 +1671,7 @@ jobs:
           CONTINUE_ON_ERROR_FLAG: ${{ needs.check-changes.outputs.continue_on_error == 'true' && '--continue-on-error' || '' }}
         run: |
           cd test
-          IS_BLACKWELL=1 python3 run_suite.py --hw cuda --suite stage-c-test-4-gpu-b200 --auto-partition-id ${{ matrix.part }} --auto-partition-size 4 --timeout-per-file 1800 $CONTINUE_ON_ERROR_FLAG
+          python3 run_suite.py --hw cuda --suite stage-c-test-4-gpu-b200 --auto-partition-id ${{ matrix.part }} --auto-partition-size 4 --timeout-per-file 1800 $CONTINUE_ON_ERROR_FLAG
 
       - uses: ./.github/actions/upload-cuda-coredumps
         if: always()
@@ -1719,7 +1717,7 @@ jobs:
   #     - name: Install dependencies
   #       timeout-minutes: 20
   #       run: |
-  #         CUSTOM_BUILD_SGL_KERNEL=${{needs.check-changes.outputs.sgl_kernel}} IS_BLACKWELL=1 GRACE_BLACKWELL=1 bash scripts/ci/cuda/ci_install_deepep.sh
+  #         CUSTOM_BUILD_SGL_KERNEL=${{needs.check-changes.outputs.sgl_kernel}} GRACE_BLACKWELL=1 bash scripts/ci/cuda/ci_install_deepep.sh
   #
   #     - name: Run test
   #       timeout-minutes: 45
diff --git a/.github/workflows/rerun-ut.yml b/.github/workflows/rerun-ut.yml
index dd544b509..feeae1850 100644
--- a/.github/workflows/rerun-ut.yml
+++ b/.github/workflows/rerun-ut.yml
@@ -48,7 +48,6 @@ jobs:
     timeout-minutes: 120
     env:
       RUNNER_LABELS: ${{ inputs.runner_label }}
-      IS_BLACKWELL: ${{ (inputs.runner_label == '1-gpu-5090' || contains(inputs.runner_label, 'b200')) && '1' || '0' }}
       SGLANG_CI_RDMA_ALL_DEVICES: ${{ inputs.runner_label == '8-gpu-h20' && 'mlx5_1,mlx5_2,mlx5_3,mlx5_4' || '' }}
     steps:
       - name: Checkout code
diff --git a/python/sglang/srt/environ.py b/python/sglang/srt/environ.py
index ec978fb33..4dcf0613b 100644
--- a/python/sglang/srt/environ.py
+++ b/python/sglang/srt/environ.py
@@ -194,7 +194,6 @@ class Envs:
     SGLANG_TEST_STUCK_SCHEDULER_INIT = EnvFloat(0)
     SGLANG_TEST_STUCK_TOKENIZER = EnvFloat(0)
     SGLANG_TEST_CRASH_AFTER_STREAM_OUTPUTS = EnvInt(0)
-    IS_BLACKWELL = EnvBool(False)
     IS_H200 = EnvBool(False)
     SGLANG_SET_CPU_AFFINITY = EnvBool(False)
     SGLANG_PROFILE_WITH_STACK = EnvBool(True)
diff --git a/python/sglang/test/test_utils.py b/python/sglang/test/test_utils.py
index 32db3c07d..ec169eaf5 100644
--- a/python/sglang/test/test_utils.py
+++ b/python/sglang/test/test_utils.py
@@ -37,6 +37,7 @@ from sglang.srt.environ import envs
 from sglang.srt.utils import (
     get_bool_env_var,
     get_device,
+    is_blackwell,
     is_cuda,
     is_xpu,
     kill_process_tree,
@@ -197,8 +198,8 @@ def is_in_amd_ci():
 
 
 def is_blackwell_system():
-    """Return whether it is running on a Blackwell (B200) system."""
-    return envs.IS_BLACKWELL.get()
+    """Same CUDA capability + toolkit semantics as ``sglang.srt.utils.is_blackwell``."""
+    return is_blackwell()
 
 
 def is_h200_system():
diff --git a/test/show_partitions.py b/test/show_partitions.py
index de1025a53..cb77791da 100755
--- a/test/show_partitions.py
+++ b/test/show_partitions.py
@@ -36,7 +36,7 @@ HW_MAPPING = {
 # Regex to detect run_suite.py invocations from pr-test.yml.
 # Uses lookaheads so --hw and --suite can appear in any order.
 _RUN_SUITE_RE = re.compile(
-    r"^\s*(?:\w+=\S+\s+)?"  # optional env prefix (e.g. IS_BLACKWELL=1)
+    r"^\s*(?:\w+=\S+\s+)?"  # optional env prefix (e.g. VAR=value)
     r"python3\s+run_suite\.py\b"
     r"(?=.*\s--hw\s+(?P<hw>\S+))"
     r"(?=.*\s--suite\s+(?P<suite>\S+))"