diff --git a/.github/workflows/context.yml b/.github/workflows/context.yml
index c6f40d1d..9dce8c74 100644
--- a/.github/workflows/context.yml
+++ b/.github/workflows/context.yml
@@ -49,3 +49,14 @@ jobs:
         name: check if a pr has test label
         run: |
           echo "- github.event.pull_request.labels has 'test'" >> "$GITHUB_STEP_SUMMARY"
+
+      - name: write sha as comment
+        uses: actions/github-script@v7
+        with:
+          script: |
+            github.rest.issues.createComment({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body: `event: ${{ github.event_name }}\n- github.event.pull_request.head.sha: ${{ github.event.pull_request.head.sha }}\n - github.sha: ${{ github.sha }}`
+            })
diff --git a/README.md b/README.md
index fea088f2..350116dc 100644
--- a/README.md
+++ b/README.md
@@ -7,6 +7,9 @@
 
 ### 1. pull_request
 
+- `github.sha` is not the latest commit sha [ref](https://sue445.hatenablog.com/entry/2021/01/07/004835)
+- `github.event.pull_request.head.sha` is the sha of the lastest commit [ref](https://github.com/orgs/community/discussions/26676)
+
 |GitHub Actions|Trigger|Description|
 |---|---|---|
 |[actionlint](.github/workflows/actionlint.yml)| pull_request | [actionlint](https://github.com/rhysd/actionlint) lint for GitHub Actions workflows|