diff --git a/.github/workflows/mantis-discord-status-reactions.yml b/.github/workflows/mantis-discord-status-reactions.yml
index 5ce773d5b38..c16446a8f43 100644
--- a/.github/workflows/mantis-discord-status-reactions.yml
+++ b/.github/workflows/mantis-discord-status-reactions.yml
@@ -255,23 +255,23 @@ jobs:
       - name: Build Mantis harness
         run: pnpm build
 
+      - name: Setup Go for Crabbox CLI
+        uses: actions/setup-go@v6
+        with:
+          go-version: "1.26.x"
+          cache: false
+
       - name: Install Crabbox CLI
-        env:
-          GH_TOKEN: ${{ github.token }}
         shell: bash
         run: |
           set -euo pipefail
           install_dir="${RUNNER_TEMP}/crabbox"
           mkdir -p "$install_dir" "$HOME/.local/bin"
-          gh release download \
-            --repo openclaw/crabbox \
-            --pattern 'crabbox_*_linux_amd64.tar.gz' \
-            --dir "$install_dir" \
-            --clobber
-          tar -xzf "$install_dir"/crabbox_*_linux_amd64.tar.gz -C "$install_dir"
-          install -m 0755 "$install_dir/crabbox" "$HOME/.local/bin/crabbox"
+          git clone --depth 1 https://github.com/openclaw/crabbox.git "$install_dir/src"
+          go build -C "$install_dir/src" -o "$HOME/.local/bin/crabbox" ./cmd/crabbox
           echo "$HOME/.local/bin" >> "$GITHUB_PATH"
           "$HOME/.local/bin/crabbox" --version
+          "$HOME/.local/bin/crabbox" warmup --help 2>&1 | grep -q -- "--desktop"
 
       - name: Prepare baseline and candidate worktrees
         shell: bash
diff --git a/docs/concepts/mantis.md b/docs/concepts/mantis.md
index 49826a33c9c..8c0602e9bd8 100644
--- a/docs/concepts/mantis.md
+++ b/docs/concepts/mantis.md
@@ -123,7 +123,9 @@ worktrees, runs `discord-status-reactions-tool-only` against each worktree, and
 uploads `baseline/`, `candidate/`, `comparison.json`, and `mantis-report.md` as
 Actions artifacts. It also renders each lane's timeline HTML in a Crabbox
 desktop browser and publishes those VNC screenshots beside the deterministic
-timeline PNGs in the PR comment.
+timeline PNGs in the PR comment. The workflow builds the Crabbox CLI from
+`openclaw/crabbox` main so it can use the current desktop/browser lease flags
+before the next Crabbox binary release is cut.
 
 You can also trigger the status-reactions run directly from a PR comment: