diff --git a/.forgejo/workflows/ci.yml b/.forgejo/workflows/ci.yml
new file mode 100644
index 0000000..0eae641
--- /dev/null
+++ b/.forgejo/workflows/ci.yml
@@ -0,0 +1,84 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+  workflow_dispatch:
+
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    runs-on: grunt
+    steps:
+      - name: Checkout
+        uses: https://${{ secrets.READ_REPO_TOKEN }}@git.wxs.ro/xternal/checkout@v6.0.2
+        with:
+          fetch-depth: 1
+
+      - name: Install Bun
+        run: |
+          if command -v bun &> /dev/null; then
+            echo "Bun already installed: $(bun --version)"
+          else
+            curl -fsSL https://bun.sh/install | bash
+            echo "$HOME/.bun/bin" >> "$GITHUB_PATH"
+          fi
+
+      - name: Install dependencies
+        run: bun install
+
+      - name: Run tests
+        run: bun test
+
+  prettier:
+    runs-on: grunt
+    steps:
+      - name: Checkout
+        uses: https://${{ secrets.READ_REPO_TOKEN }}@git.wxs.ro/xternal/checkout@v6.0.2
+        with:
+          fetch-depth: 1
+
+      - name: Install Bun
+        run: |
+          if command -v bun &> /dev/null; then
+            echo "Bun already installed: $(bun --version)"
+          else
+            curl -fsSL https://bun.sh/install | bash
+            echo "$HOME/.bun/bin" >> "$GITHUB_PATH"
+          fi
+
+      - name: Install dependencies
+        run: bun install
+
+      - name: Run prettier check
+        run: bun run format:check
+
+  typecheck:
+    runs-on: grunt
+    steps:
+      - name: Checkout
+        uses: https://${{ secrets.READ_REPO_TOKEN }}@git.wxs.ro/xternal/checkout@v6.0.2
+        with:
+          fetch-depth: 1
+
+      - name: Install Bun
+        run: |
+          if command -v bun &> /dev/null; then
+            echo "Bun already installed: $(bun --version)"
+          else
+            curl -fsSL https://bun.sh/install | bash
+            echo "$HOME/.bun/bin" >> "$GITHUB_PATH"
+          fi
+
+      - name: Install dependencies
+        run: bun install
+
+      - name: Run TypeScript type check
+        run: bun run typecheck
diff --git a/.forgejo/workflows/test-action.yml b/.forgejo/workflows/test-action.yml
new file mode 100644
index 0000000..cd444d5
--- /dev/null
+++ b/.forgejo/workflows/test-action.yml
@@ -0,0 +1,80 @@
+name: Test Action (Forgejo)
+
+on:
+  schedule:
+    # Weekly Monday at 06:00 UTC
+    - cron: "0 6 * * 1"
+  pull_request:
+    branches:
+      - main
+    paths:
+      - "src/**"
+      - "action.yml"
+      - ".forgejo/**"
+      - "base-action/**"
+  workflow_dispatch:
+
+concurrency:
+  group: test-action-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test-agent-mode:
+    name: Test Agent Mode on Forgejo
+    runs-on: grunt
+    steps:
+      - name: Checkout
+        uses: https://${{ secrets.READ_REPO_TOKEN }}@git.wxs.ro/xternal/checkout@v6.0.2
+        with:
+          fetch-depth: 1
+
+      - name: Run Claude Code Action (agent mode)
+        id: claude
+        uses: ./
+        with:
+          prompt: "Respond with exactly the text FORGEJO_PLATFORM_TEST_OK and nothing else. Do not use any tools."
+          claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
+          github_token: ${{ secrets.FORGEJO_CLAUDE_TOKEN }}
+          platform: "forgejo"
+        env:
+          ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }}
+
+      - name: Verify execution output exists
+        run: |
+          EXEC_FILE="${{ steps.claude.outputs.execution_file }}"
+          if [ -z "$EXEC_FILE" ]; then
+            echo "FAIL: execution_file output is empty"
+            exit 1
+          fi
+          if [ ! -f "$EXEC_FILE" ]; then
+            echo "FAIL: execution file does not exist at: $EXEC_FILE"
+            exit 1
+          fi
+          echo "OK: execution file exists at: $EXEC_FILE"
+
+          # Check that the output contains our test marker
+          if grep -q "FORGEJO_PLATFORM_TEST_OK" "$EXEC_FILE"; then
+            echo "OK: Output contains expected test marker"
+          else
+            echo "WARN: Test marker not found in output (Claude may have formatted differently)"
+            echo "--- Output contents (first 50 lines) ---"
+            head -50 "$EXEC_FILE"
+          fi
+
+      - name: Debug on failure
+        if: failure()
+        run: |
+          echo "=== Debug Info ==="
+          echo "Platform env: PLATFORM=$PLATFORM FORGEJO=$FORGEJO"
+          echo "Server URL: $GITHUB_SERVER_URL"
+          echo "API URL: $GITHUB_API_URL"
+          echo "Event: ${{ github.event_name }}"
+          echo "Actor: ${{ github.actor }}"
+          echo ""
+          EXEC_FILE="${{ steps.claude.outputs.execution_file }}"
+          if [ -f "$EXEC_FILE" ]; then
+            echo "--- Execution file contents ---"
+            cat "$EXEC_FILE"
+          else
+            echo "No execution file found"
+          fi
diff --git a/.forgejo/workflows/upstream-sync.yml b/.forgejo/workflows/upstream-sync.yml
new file mode 100644
index 0000000..2015826
--- /dev/null
+++ b/.forgejo/workflows/upstream-sync.yml
@@ -0,0 +1,176 @@
+name: Upstream Sync Check
+
+on:
+  schedule:
+    # Weekly Monday at 08:00 UTC
+    - cron: "0 8 * * 1"
+  workflow_dispatch:
+
+jobs:
+  check-upstream:
+    name: Check for upstream updates
+    runs-on: grunt
+    steps:
+      - name: Checkout
+        uses: https://${{ secrets.READ_REPO_TOKEN }}@git.wxs.ro/xternal/checkout@v6.0.2
+        with:
+          fetch-depth: 0
+
+      - name: Configure upstream remote
+        run: |
+          if ! git remote get-url upstream &> /dev/null; then
+            git remote add upstream https://github.com/anthropics/claude-code-action.git
+          fi
+
+      - name: Fetch upstream
+        run: git fetch upstream main --quiet
+
+      - name: Compare with upstream
+        id: compare
+        run: |
+          BEHIND_COUNT=$(git rev-list main..upstream/main --count)
+          AHEAD_COUNT=$(git rev-list upstream/main..main --count)
+
+          echo "behind=$BEHIND_COUNT" >> "$GITHUB_OUTPUT"
+          echo "ahead=$AHEAD_COUNT" >> "$GITHUB_OUTPUT"
+
+          echo "Our main is $BEHIND_COUNT commits behind and $AHEAD_COUNT commits ahead of upstream"
+
+          if [ "$BEHIND_COUNT" -gt 0 ]; then
+            echo "needs_sync=true" >> "$GITHUB_OUTPUT"
+
+            # Generate diff summary
+            echo "--- New upstream commits ---"
+            git log main..upstream/main --oneline | head -30
+
+            echo ""
+            echo "--- Files changed ---"
+            DIFF_STAT=$(git diff --stat main...upstream/main)
+            echo "$DIFF_STAT"
+
+            # Save for issue body (escape newlines for multiline output)
+            {
+              echo "diff_stat<<DIFF_EOF"
+              echo "$DIFF_STAT"
+              echo "DIFF_EOF"
+            } >> "$GITHUB_OUTPUT"
+
+            {
+              echo "commit_log<<LOG_EOF"
+              git log main..upstream/main --oneline | head -30
+              echo "LOG_EOF"
+            } >> "$GITHUB_OUTPUT"
+          else
+            echo "needs_sync=false" >> "$GITHUB_OUTPUT"
+            echo "Already up to date with upstream"
+          fi
+
+      - name: Check for existing sync issue
+        if: steps.compare.outputs.needs_sync == 'true'
+        id: existing
+        run: |
+          # Search for open issues with the upstream-sync label
+          RESPONSE=$(curl -s \
+            -H "Authorization: token ${{ github.token }}" \
+            -H "Content-Type: application/json" \
+            "${GITHUB_API_URL}/repos/${{ github.repository }}/issues?state=open&labels=upstream-sync&limit=1")
+
+          ISSUE_COUNT=$(echo "$RESPONSE" | jq 'length')
+
+          if [ "$ISSUE_COUNT" -gt 0 ]; then
+            ISSUE_NUMBER=$(echo "$RESPONSE" | jq '.[0].number')
+            echo "issue_exists=true" >> "$GITHUB_OUTPUT"
+            echo "issue_number=$ISSUE_NUMBER" >> "$GITHUB_OUTPUT"
+            echo "Found existing sync issue #$ISSUE_NUMBER"
+          else
+            echo "issue_exists=false" >> "$GITHUB_OUTPUT"
+            echo "No existing sync issue found"
+          fi
+
+      - name: Create upstream-sync label
+        if: steps.compare.outputs.needs_sync == 'true'
+        run: |
+          # Create label if it doesn't exist (ignore 409 conflict)
+          curl -s -o /dev/null -w "%{http_code}" \
+            -X POST \
+            -H "Authorization: token ${{ github.token }}" \
+            -H "Content-Type: application/json" \
+            -d '{"name":"upstream-sync","color":"#0075ca","description":"Upstream sync tracking"}' \
+            "${GITHUB_API_URL}/repos/${{ github.repository }}/labels" || true
+
+      - name: Create or update sync issue
+        if: steps.compare.outputs.needs_sync == 'true'
+        run: |
+          BEHIND="${{ steps.compare.outputs.behind }}"
+          AHEAD="${{ steps.compare.outputs.ahead }}"
+          COMMIT_LOG=$(cat <<'LOG_EOF'
+          ${{ steps.compare.outputs.commit_log }}
+          LOG_EOF
+          )
+          DIFF_STAT=$(cat <<'DIFF_EOF'
+          ${{ steps.compare.outputs.diff_stat }}
+          DIFF_EOF
+          )
+
+          BODY=$(cat <<BODY_EOF
+          ## Upstream Sync Required
+
+          Our \`main\` branch is **${BEHIND} commits behind** upstream (\`anthropics/claude-code-action\`).
+          We are **${AHEAD} commits ahead** (our Forgejo-specific changes).
+
+          ### New upstream commits (latest ${BEHIND}, max 30 shown)
+
+          \`\`\`
+          ${COMMIT_LOG}
+          \`\`\`
+
+          ### Files changed
+
+          \`\`\`
+          ${DIFF_STAT}
+          \`\`\`
+
+          ### How to merge
+
+          \`\`\`bash
+          git fetch upstream main
+          git merge upstream/main
+          # Resolve any conflicts in the 3-4 modified files (run.ts, tag/index.ts, etc.)
+          bun test
+          git push origin main
+          \`\`\`
+
+          ### Conflict-prone files
+
+          These files have Forgejo modifications and may conflict:
+          - \`src/entrypoints/run.ts\`
+          - \`src/modes/tag/index.ts\`
+          - \`src/mcp/install-mcp-server.ts\`
+          - \`action.yml\`
+
+          _Auto-generated by upstream-sync workflow on $(date -u +%Y-%m-%d)_
+          BODY_EOF
+          )
+
+          TITLE="Upstream sync: ${BEHIND} new commits from anthropics/claude-code-action"
+
+          if [ "${{ steps.existing.outputs.issue_exists }}" = "true" ]; then
+            # Update existing issue
+            ISSUE_NUMBER="${{ steps.existing.outputs.issue_number }}"
+            curl -s -o /dev/null \
+              -X PATCH \
+              -H "Authorization: token ${{ github.token }}" \
+              -H "Content-Type: application/json" \
+              -d "$(jq -n --arg title "$TITLE" --arg body "$BODY" '{title: $title, body: $body}')" \
+              "${GITHUB_API_URL}/repos/${{ github.repository }}/issues/${ISSUE_NUMBER}"
+            echo "Updated existing issue #${ISSUE_NUMBER}"
+          else
+            # Create new issue
+            curl -s -o /dev/null \
+              -X POST \
+              -H "Authorization: token ${{ github.token }}" \
+              -H "Content-Type: application/json" \
+              -d "$(jq -n --arg title "$TITLE" --arg body "$BODY" '{title: $title, body: $body, labels: [{"name": "upstream-sync"}]}')" \
+              "${GITHUB_API_URL}/repos/${{ github.repository }}/issues"
+            echo "Created new upstream sync issue"
+          fi
diff --git a/prds/1-forgejo-platform-support.md b/prds/1-forgejo-platform-support.md
index 0fee75b..67bc957 100644
--- a/prds/1-forgejo-platform-support.md
+++ b/prds/1-forgejo-platform-support.md
@@ -245,7 +245,8 @@ The upstream repo has 13 workflows in `.github/workflows/`. Strategy:
   - Depends on: M1
   - Success: Token is available without OIDC on Forgejo. GitHub path unchanged.
 
-- [ ] **M3: Forgejo CI workflows** — Create `.forgejo/workflows/` with CI, self-test, and upstream sync workflows. Document runner configuration requirements.
+- [x] **M3: Forgejo CI workflows** — Created `.forgejo/workflows/` with three workflows adapted for Forgejo `grunt` runner: `ci.yml` (3 separate jobs: test, prettier, typecheck using curl-based bun install + `xternal/checkout`), `test-action.yml` (agent-mode self-test with `FORGEJO_PLATFORM_TEST_OK` marker, runs weekly + on PRs to src/action.yml/.forgejo), `upstream-sync.yml` (weekly upstream check, creates/updates issue with `upstream-sync` label including commit log, diff stat, and merge instructions).
+
   - Files: `.forgejo/workflows/ci.yml`, `.forgejo/workflows/test-action.yml`, `.forgejo/workflows/upstream-sync.yml` (all NEW)
   - Success: CI runs tests on push. Upstream `.github/workflows/` don't interfere.