diff --git a/.github/workflows/pr-size-label.yml b/.github/workflows/pr-size-label.yml
new file mode 100644
index 00000000000..a36d2375ed2
--- /dev/null
+++ b/.github/workflows/pr-size-label.yml
@@ -0,0 +1,147 @@
+name: PR Size Label
+
+on:
+  pull_request_target:
+    types:
+    - opened
+    - reopened
+    - synchronize
+  workflow_dispatch:
+
+
+permissions:
+  contents: read
+  issues: write
+  pull-requests: write
+
+jobs:
+  Label:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Label PR by filtered changed lines
+      uses: actions/github-script@v7
+      with:
+        github-token: ${{ secrets.GITHUB_TOKEN }}
+        script: |
+          const owner = context.repo.owner
+          const repo = context.repo.repo
+          const ignoredFilePatterns = [
+            /(?:^|\/)\.cnb\/.+\.ya?ml$/i,
+            /(?:^|\/)\.gemini\/.+\.ya?ml$/i,
+            /(?:^|\/)\.gitee\/.+\.ya?ml$/i,
+            /(?:^|\/)\.github\/.+\.ya?ml$/i,
+            /(?:^|\/)\.idea\/.+\.xml$/i,
+            /(?:^|\/)\.editorconfig$/i,
+            /(?:^|\/)\.gitattributes$/i,
+            /(?:^|\/)\.gitignore$/i,
+            /(?:^|\/).+\.kts$/i,
+            /(?:^|\/).+\.md$/i,
+            /(?:^|\/)LICENSE(?:_.*)?$/i,
+            /(?:^|\/)gradlew(?:\.bat|\.ps1)?$/i,
+            /(?:^|\/)gradle\/wrapper\/gradle-wrapper\.properties$/i,
+            /(?:^|\/)lang\/.+\.properties$/i,
+            /(?:^|\/)l10n\/.+\.properties$/i,
+            /(?:^|\/)checkstyle\.xml$/i,
+            /(?:^|\/).+\.(?:png|jpe?g|gif|ico|svg|json|ttf|woff2?|webp|avif|jxl|heic|mp4|webm|mp3|ogg|wav|txt|toml)$/i
+          ]
+
+          async function processPR(issue_number) {
+            const files = await github.paginate(github.rest.pulls.listFiles, {
+              owner,
+              repo,
+              pull_number: issue_number,
+              per_page: 100,
+            })
+
+            const countedFiles = []
+            const ignoredFiles = []
+            let totalChanges = 0
+
+            for (const file of files) {
+              const ignored = ignoredFilePatterns.some(pattern => pattern.test(file.filename))
+              if (ignored) {
+                ignoredFiles.push(file.filename)
+                continue
+              }
+
+              const fileChanges = file.changes ?? ((file.additions || 0) + (file.deletions || 0))
+              totalChanges += fileChanges
+              countedFiles.push(`${file.filename} (${fileChanges})`)
+            }
+
+            let targetLabel
+            if (totalChanges <= 9) targetLabel = '1+'
+            else if (totalChanges <= 39) targetLabel = '10+'
+            else if (totalChanges <= 99) targetLabel = '40+'
+            else if (totalChanges <= 499) targetLabel = '100+'
+            else if (totalChanges <= 999) targetLabel = '500+'
+            else if (totalChanges <= 1999) targetLabel = '1000+'
+            else if (totalChanges <= 4999) targetLabel = '2000+'
+            else targetLabel = '5000+'
+
+            const currentLabels = await github.paginate(github.rest.issues.listLabelsOnIssue, {
+              owner,
+              repo,
+              issue_number,
+              per_page: 100,
+            })
+
+            const sizeLabels = currentLabels
+              .map(label => label.name)
+              .filter(name => /^\d+\+$/.test(name))
+
+            for (const name of sizeLabels) {
+              if (name !== targetLabel) {
+                await github.rest.issues.removeLabel({
+                  owner,
+                  repo,
+                  issue_number,
+                  name,
+                }).catch(() => {})
+              }
+            }
+
+            if (!currentLabels.some(label => label.name === targetLabel)) {
+              await github.rest.issues.addLabels({
+                owner,
+                repo,
+                issue_number,
+                labels: [targetLabel],
+              })
+            }
+
+            core.info(`Pull request #${issue_number} has ${totalChanges} counted changed lines, applied ${targetLabel}.`)
+            core.info(`Ignored files: ${ignoredFiles.length ? ignoredFiles.join(', ') : 'none'}`)
+            core.info(`Counted files: ${countedFiles.length ? countedFiles.join(', ') : 'none'}`)
+          }
+
+          if (context.eventName === 'workflow_dispatch') {
+            core.info('Manual trigger detected. Fetching all open pull requests...')
+            
+            const openPRs = await github.paginate(github.rest.pulls.list, {
+              owner,
+              repo,
+              state: 'open',
+              per_page: 100,
+            })
+
+            const unlabelledPRs = openPRs.filter(pr => {
+              return !pr.labels.some(label => /^\d+\+$/.test(label.name))
+            })
+
+            core.info(`Found ${openPRs.length} open pull request(s), ${unlabelledPRs.length} of them lack a size label.`)
+
+            for (const pr of unlabelledPRs) {
+              core.info(`----------------------------------------`)
+              core.info(`Processing unlabelled pull request #${pr.number}: ${pr.title}`)
+              await processPR(pr.number)
+            }
+          } else {
+            const pr = context.payload.pull_request
+            if (!pr) {
+              core.info('No pull request found in payload, skipping.')
+              return
+            }
+            await processPR(pr.number)
+          }
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