diff --git a/.github/workflows/pr-test-amd.yml b/.github/workflows/pr-test-amd.yml
index dd9472b7c..a94b1ee73 100644
--- a/.github/workflows/pr-test-amd.yml
+++ b/.github/workflows/pr-test-amd.yml
@@ -24,6 +24,11 @@ on:
         required: false
         type: string
         default: ""
+      pr_head_sha:
+        description: "PR head SHA to checkout (for /rerun-stage on fork PRs)"
+        required: false
+        type: string
+        default: ""
   workflow_call:
     inputs:
       ref:
@@ -36,8 +41,10 @@ on:
         required: false
         type: boolean
         default: false
+
 concurrency:
-  group: pr-test-amd-${{ inputs.ref || github.ref }}
+  # Include pr_head_sha in group for /rerun-stage dispatches to avoid collisions with main branch runs
+  group: pr-test-amd-${{ inputs.pr_head_sha || inputs.ref || github.ref }}
   cancel-in-progress: ${{ github.event_name != 'workflow_call' }}
 
 jobs:
@@ -55,7 +62,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Determine run mode
         id: run-mode
@@ -110,7 +117,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Ensure VRAM is clear
         run: bash scripts/ensure_vram_clear.sh rocm
@@ -158,7 +165,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Ensure VRAM is clear
         run: bash scripts/ensure_vram_clear.sh rocm
@@ -191,7 +198,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Ensure VRAM is clear
         run: bash scripts/ensure_vram_clear.sh rocm
@@ -312,7 +319,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Ensure VRAM is clear
         run: bash scripts/ensure_vram_clear.sh rocm
@@ -439,7 +446,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Ensure VRAM is clear
         run: bash scripts/ensure_vram_clear.sh rocm
@@ -479,7 +486,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Ensure VRAM is clear
         run: bash scripts/ensure_vram_clear.sh rocm
@@ -521,7 +528,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Ensure VRAM is clear
         run: bash scripts/ensure_vram_clear.sh rocm
@@ -566,7 +573,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Ensure VRAM is clear
         run: bash scripts/ensure_vram_clear.sh rocm
@@ -621,7 +628,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Ensure VRAM is clear
         run: bash scripts/ensure_vram_clear.sh rocm
@@ -670,7 +677,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Ensure VRAM is clear
         run: bash scripts/ensure_vram_clear.sh rocm
@@ -729,7 +736,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Ensure VRAM is clear
         run: bash scripts/ensure_vram_clear.sh rocm
@@ -771,7 +778,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Ensure VRAM is clear
         run: bash scripts/ensure_vram_clear.sh rocm
diff --git a/.github/workflows/pr-test.yml b/.github/workflows/pr-test.yml
index 5c0dcd7f2..e740f6af6 100644
--- a/.github/workflows/pr-test.yml
+++ b/.github/workflows/pr-test.yml
@@ -25,6 +25,11 @@ on:
         required: false
         type: boolean
         default: false
+      pr_head_sha:
+        description: "PR head SHA to checkout (for /rerun-stage on fork PRs)"
+        required: false
+        type: string
+        default: ""
   workflow_call:
     inputs:
       ref:
@@ -39,7 +44,8 @@ on:
         default: false
 
 concurrency:
-  group: pr-test-${{ inputs.ref || github.ref }}
+  # Include pr_head_sha in group for /rerun-stage dispatches to avoid collisions with main branch runs
+  group: pr-test-${{ inputs.pr_head_sha || inputs.ref || github.ref }}
   cancel-in-progress: ${{ github.event_name != 'workflow_call' }}
 
 env:
@@ -62,7 +68,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Determine run mode
         id: run-mode
@@ -190,7 +196,7 @@ jobs:
       - uses: actions/checkout@v4
         with:
           submodules: "recursive"
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v5
@@ -232,7 +238,7 @@ jobs:
       - uses: actions/checkout@v4
         with:
           submodules: "recursive"
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v5
@@ -261,7 +267,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Cleanup
         run: |
@@ -294,7 +300,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Cleanup
         run: |
@@ -328,7 +334,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Cleanup
         run: |
@@ -373,7 +379,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Cleanup
         run: |
@@ -432,14 +438,16 @@ jobs:
 
   jit-kernel-unit-test:
     needs: [check-changes, call-gate]
-    if: needs.check-changes.outputs.jit_kernel == 'true'
+    if: |
+      !inputs.target_stage &&
+      needs.check-changes.outputs.jit_kernel == 'true'
     runs-on: 1-gpu-runner
     env:
       RUNNER_LABELS: 1-gpu-runner
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Install dependencies
         run: |
@@ -472,7 +480,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -521,7 +529,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -564,7 +572,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -607,7 +615,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -650,7 +658,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -693,7 +701,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -734,7 +742,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -783,7 +791,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -828,7 +836,7 @@ jobs:
         - name: Checkout code
           uses: actions/checkout@v4
           with:
-            ref: ${{ inputs.ref || github.ref }}
+            ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
         - name: Download artifacts
           if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -880,7 +888,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -931,7 +939,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -979,7 +987,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -1030,7 +1038,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -1081,7 +1089,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -1139,7 +1147,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -1186,7 +1194,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -1257,7 +1265,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -1320,7 +1328,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -1377,7 +1385,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -1446,7 +1454,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -1488,7 +1496,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -1530,7 +1538,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -1577,7 +1585,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -1629,7 +1637,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
@@ -1678,7 +1686,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: ${{ inputs.ref || github.ref }}
+          ref: ${{ inputs.pr_head_sha || inputs.ref || github.sha }}
 
       - name: Download artifacts
         if: needs.check-changes.outputs.sgl_kernel == 'true'
diff --git a/scripts/ci/slash_command_handler.py b/scripts/ci/slash_command_handler.py
index a69bf5c85..f251e4a36 100644
--- a/scripts/ci/slash_command_handler.py
+++ b/scripts/ci/slash_command_handler.py
@@ -215,15 +215,38 @@ def handle_rerun_stage(
             print(f"Error: {workflow_name} workflow not found")
             return False
 
-        # Trigger workflow_dispatch on the PR's head branch
-        ref = pr.head.ref
-        print(f"Triggering {workflow_name} workflow on branch: {ref}")
+        # Check if PR is from a fork by comparing repo owners
+        # Handle case where fork repo may have been deleted (pr.head.repo is None)
+        is_fork = (
+            pr.head.repo is None or pr.head.repo.owner.login != gh_repo.owner.login
+        )
+        print(f"PR is from fork: {is_fork}")
 
-        # AMD workflow doesn't have version input, only target_stage
-        if is_amd_stage:
-            inputs = {"target_stage": stage_name}
+        if is_fork:
+            # For fork PRs: dispatch on main and pass SHA as input
+            # This is needed because fork branch names don't exist in the main repo
+            ref = "main"
+            pr_head_sha = pr.head.sha
+            print(
+                f"Triggering {workflow_name} workflow on ref: {ref}, PR head SHA: {pr_head_sha}"
+            )
+            if is_amd_stage:
+                inputs = {"target_stage": stage_name, "pr_head_sha": pr_head_sha}
+            else:
+                inputs = {
+                    "version": "release",
+                    "target_stage": stage_name,
+                    "pr_head_sha": pr_head_sha,
+                }
         else:
-            inputs = {"version": "release", "target_stage": stage_name}
+            # For non-fork PRs: dispatch on the PR branch directly
+            # This allows testing workflow changes before merge
+            ref = pr.head.ref
+            print(f"Triggering {workflow_name} workflow on branch: {ref}")
+            if is_amd_stage:
+                inputs = {"target_stage": stage_name}
+            else:
+                inputs = {"version": "release", "target_stage": stage_name}
 
         # Use requests directly as PyGithub's create_dispatch only accepts HTTP 204
         dispatch_url = f"https://api.github.com/repos/{gh_repo.full_name}/actions/workflows/{target_workflow.id}/dispatches"