diff --git a/.github/workflows/auto-retarget-main-pr-to-dev.yml b/.github/workflows/auto-retarget-main-pr-to-dev.yml
deleted file mode 100644
index 3732a72359..0000000000
--- a/.github/workflows/auto-retarget-main-pr-to-dev.yml
+++ /dev/null
@@ -1,73 +0,0 @@
-name: auto-retarget-main-pr-to-dev
-
-on:
-  pull_request_target:
-    types:
-      - opened
-      - reopened
-      - edited
-    branches:
-      - main
-
-permissions:
-  contents: read
-  issues: write
-  pull-requests: write
-
-jobs:
-  retarget:
-    if: github.actor != 'github-actions[bot]'
-    runs-on: ubuntu-latest
-    steps:
-      - name: Retarget PR base to dev
-        uses: actions/github-script@v7
-        with:
-          script: |
-            const pr = context.payload.pull_request;
-            const prNumber = pr.number;
-            const { owner, repo } = context.repo;
-
-            const baseRef = pr.base?.ref;
-            const headRef = pr.head?.ref;
-            const desiredBase = "dev";
-
-            if (baseRef !== "main") {
-              core.info(`PR #${prNumber} base is ${baseRef}; nothing to do.`);
-              return;
-            }
-
-            if (headRef === desiredBase) {
-              core.info(`PR #${prNumber} is ${desiredBase} -> main; skipping retarget.`);
-              return;
-            }
-
-            core.info(`Retargeting PR #${prNumber} base from ${baseRef} to ${desiredBase}.`);
-
-            try {
-              await github.rest.pulls.update({
-                owner,
-                repo,
-                pull_number: prNumber,
-                base: desiredBase,
-              });
-            } catch (error) {
-              core.setFailed(`Failed to retarget PR #${prNumber} to ${desiredBase}: ${error.message}`);
-              return;
-            }
-
-            const body = [
-              `This pull request targeted \`${baseRef}\`.`,
-              "",
-              `The base branch has been automatically changed to \`${desiredBase}\`.`,
-            ].join("\n");
-
-            try {
-              await github.rest.issues.createComment({
-                owner,
-                repo,
-                issue_number: prNumber,
-                body,
-              });
-            } catch (error) {
-              core.warning(`Failed to comment on PR #${prNumber}: ${error.message}`);
-            }
diff --git a/.github/workflows/auto-sync-upstream-copilot.yml b/.github/workflows/auto-sync-upstream-copilot.yml
new file mode 100644
index 0000000000..5af4fda4d7
--- /dev/null
+++ b/.github/workflows/auto-sync-upstream-copilot.yml
@@ -0,0 +1,171 @@
+name: auto-sync-upstream-copilot
+
+on:
+  schedule:
+    # daily at 02:30 UTC (10:30 Asia/Singapore) — offset 30m from auto-sync-upstream
+    - cron: '30 2 * * *'
+  workflow_dispatch:
+
+permissions:
+  contents: write
+  pull-requests: write
+  issues: write
+  actions: write
+
+concurrency:
+  group: auto-sync-upstream-copilot
+  cancel-in-progress: false
+
+env:
+  UPSTREAM_URL: https://github.com/router-for-me/CLIProxyAPI.git
+  UPSTREAM_BRANCH: main
+  TARGET_BRANCH: feat/copilot
+  PR_BRANCH: auto-sync/upstream-main-copilot
+
+jobs:
+  sync:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout target branch
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ env.TARGET_BRANCH }}
+          fetch-depth: 0
+
+      - name: Configure git identity
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+
+      - name: Add upstream remote and fetch
+        run: |
+          git remote add upstream "$UPSTREAM_URL"
+          git fetch upstream "$UPSTREAM_BRANCH"
+
+      - name: Check if behind upstream
+        id: check
+        run: |
+          BEHIND=$(git rev-list --count "HEAD..upstream/${UPSTREAM_BRANCH}")
+          echo "behind=$BEHIND" >> "$GITHUB_OUTPUT"
+          if [ "$BEHIND" = "0" ]; then
+            echo "Already up to date with upstream/${UPSTREAM_BRANCH}."
+          else
+            echo "$BEHIND new commits from upstream:"
+            git log --oneline "HEAD..upstream/${UPSTREAM_BRANCH}"
+          fi
+
+      - name: Build merge commit message
+        if: steps.check.outputs.behind != '0'
+        run: |
+          {
+            echo "Merge upstream/${UPSTREAM_BRANCH} (auto-sync feat/copilot)"
+            echo
+            git log --reverse --pretty=format:'- %h %s' "HEAD..upstream/${UPSTREAM_BRANCH}"
+            echo
+          } > /tmp/merge-msg.txt
+          cat /tmp/merge-msg.txt
+
+      - name: Try clean merge
+        if: steps.check.outputs.behind != '0'
+        id: merge
+        run: |
+          set +e
+          git merge --no-ff -F /tmp/merge-msg.txt "upstream/${UPSTREAM_BRANCH}"
+          rc=$?
+          if [ "$rc" = "0" ]; then
+            echo "clean=true" >> "$GITHUB_OUTPUT"
+          else
+            echo "clean=false" >> "$GITHUB_OUTPUT"
+            git merge --abort || true
+          fi
+          exit 0
+
+      - name: Set up Go
+        if: steps.merge.outputs.clean == 'true'
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+          cache: true
+
+      - name: Verify build
+        if: steps.merge.outputs.clean == 'true'
+        id: build
+        run: |
+          set +e
+          go build -o /tmp/cli-proxy-api ./cmd/server
+          rc=$?
+          rm -f /tmp/cli-proxy-api
+          if [ "$rc" = "0" ]; then
+            echo "ok=true" >> "$GITHUB_OUTPUT"
+          else
+            echo "ok=false" >> "$GITHUB_OUTPUT"
+          fi
+          exit 0
+
+      - name: Push merged changes to target branch
+        if: steps.merge.outputs.clean == 'true' && steps.build.outputs.ok == 'true'
+        run: git push origin "${TARGET_BRANCH}"
+
+      - name: Trigger downstream image build
+        if: steps.merge.outputs.clean == 'true' && steps.build.outputs.ok == 'true'
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: gh workflow run ghcr-feat-copilot.yml --repo "${{ github.repository }}" --ref "${TARGET_BRANCH}"
+
+      - name: Prepare PR branch (build failure case)
+        if: steps.merge.outputs.clean == 'true' && steps.build.outputs.ok != 'true'
+        run: |
+          # HEAD is the (clean) merge commit — push it as the PR branch so reviewers
+          # see exactly what would land, and pr-test-build.yml runs against it.
+          git push --force origin "HEAD:refs/heads/${PR_BRANCH}"
+
+      - name: Prepare PR branch (conflict case)
+        if: steps.check.outputs.behind != '0' && steps.merge.outputs.clean != 'true'
+        run: |
+          # Reset working tree, then push raw upstream tip as the PR branch so GitHub
+          # surfaces the conflict against feat/copilot and offers web-based resolution.
+          git reset --hard "origin/${TARGET_BRANCH}"
+          git checkout -B "${PR_BRANCH}" "upstream/${UPSTREAM_BRANCH}"
+          git push --force origin "${PR_BRANCH}"
+
+      - name: Open or update sync PR
+        if: steps.check.outputs.behind != '0' && (steps.merge.outputs.clean != 'true' || steps.build.outputs.ok != 'true')
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          GH_REPO: ${{ github.repository }}
+        run: |
+          set -e
+
+          if [ "${{ steps.merge.outputs.clean }}" != "true" ]; then
+            REASON='conflicts with `'"${TARGET_BRANCH}"'`'
+          else
+            REASON='merge clean but `go build` failed'
+          fi
+
+          {
+            echo "Auto-sync from \`upstream/${UPSTREAM_BRANCH}\` (router-for-me/CLIProxyAPI) into \`${TARGET_BRANCH}\`."
+            echo
+            echo "**Reason for manual review:** ${REASON}"
+            echo
+            echo "### New commits"
+            git log --reverse --pretty=format:'- %h %s' "origin/${TARGET_BRANCH}..upstream/${UPSTREAM_BRANCH}"
+          } > /tmp/pr-body.md
+
+          # Idempotently ensure the label exists.
+          gh label create auto-sync-copilot --color FBCA04 --description "Automated upstream sync (feat/copilot)" || true
+
+          EXISTING=$(gh pr list --head "${PR_BRANCH}" --base "${TARGET_BRANCH}" --state open --json number --jq '.[0].number' || true)
+
+          TITLE="auto-sync(copilot): merge upstream/${UPSTREAM_BRANCH} (${REASON})"
+
+          if [ -n "$EXISTING" ]; then
+            gh pr edit "$EXISTING" --title "$TITLE" --body-file /tmp/pr-body.md
+            echo "Updated existing PR #$EXISTING"
+          else
+            gh pr create \
+              --base "${TARGET_BRANCH}" \
+              --head "${PR_BRANCH}" \
+              --title "$TITLE" \
+              --body-file /tmp/pr-body.md \
+              --label auto-sync-copilot
+          fi