diff --git a/.github/scripts/compare-packages-size.js b/.github/scripts/compare-packages-size.js
index 172b39e..b1e6a5c 100644
--- a/.github/scripts/compare-packages-size.js
+++ b/.github/scripts/compare-packages-size.js
@@ -1,8 +1,10 @@
 import path from "node:path";
 import { execSync as exec } from "node:child_process";
-import { statSync as stat, existsSync as exists } from "node:fs";
+import { statSync as stat, existsSync as exists, writeFileSync as write_file } from "node:fs";
 import { globSync as glob } from "glob";
 
+const MAIN_WORKTREE = ".worktrees/main";
+
 function size(file) {
     return exists(file) ? stat(file).size : null;
 }
@@ -17,44 +19,73 @@ function format(bytes) {
         : `${bytes} B`;
 }
 
-function delta(a, b) {
-    if (a == null || b == null) {
+function delta(pr, main) {
+    if (pr == null || main == null) {
         return null;
     }
-    return a - b;
+    return pr - main;
 }
 
-function icon(d) {
-    if (d == null) {
+function icon(delta) {
+    if (delta == null) {
         return "—";
     }
 
-    if (d > 0) return "⬆️";
-    if (d < 0) return "⬇️";
-    return "➡️";
+    if (delta > 0) return "🔴";
+    if (delta < 0) return "🟢";
+    return "";
 }
 
-const pr_files = glob("dist/**/*.min.js");
-const pr_sizes = Object.fromEntries(pr_files.map(f => [f, size(f)]));
-
-exec("git fetch origin main", { stdio: "inherit" });
-exec("git checkout origin/main", { stdio: "ignore" });
-exec("npm ci --include=dev", { stdio: "inherit" });
-exec("npm run build", { stdio: "inherit" });
-
-const main_sizes = Object.fromEntries(pr_files.map(f => [f, size(f)]));
+function has_local_origin_main() {
+    try {
+        exec('git show-ref --verify --quiet refs/remotes/origin/main', { stdio: ["pipe", "pipe", "pipe"] });
+        return true;
+    }
+    catch {
+        return false;
+    }
+}
 
-let md = `
+function generate_report(files, pr, main) {
+    let md = `
 ### 📦 Bundle size comparison
 
-| Name | main | PR | Δ |
-|------|------|----|---|
+| Name | main | PR | Δ | Delta  |
+|------|-----:|---:|---|-------:|
 `;
 
-for (const file of pr_files) {
-    const d = delta(pr_sizes[file], main_sizes[file]);
+    for (const file of files) {
+        const d = delta(pr[file], main[file]);
+
+        md += `| ${path.basename(file)} | ${format(main[file])} | ${format(pr[file])} | ${icon(d)} | ${format(d)} |\n`;
+    }
 
-    md += `| \`${path.basename(file)}\` | ${format(main_sizes[file])} | ${format(pr_sizes[file])} | ${icon(d)} ${format(d)} |\n`;
+    console.log(md);
+    process.env.SIZE_REPORT_OUTPUT && write_file(process.env.SIZE_REPORT_OUTPUT, md.trim());
 }
 
-console.log(md);
+try {
+    //
+    // PR build
+    //
+    exec("npm run build", { stdio: "inherit" });
+
+    const pr_files = glob("dist/**/*.min.js");
+    const pr_sizes = Object.fromEntries(pr_files.map(f => [f, size(f)]));
+
+    //
+    // Main build
+    //
+    has_local_origin_main() || exec("git fetch origin main", { stdio: "inherit" });
+    exec(`git worktree add ${MAIN_WORKTREE} origin/main`, { stdio: "ignore" });
+    exec("npm ci --include=dev", { cwd: MAIN_WORKTREE, stdio: "inherit" });
+    exec("npm run build", { cwd: MAIN_WORKTREE, stdio: "inherit" });
+
+    const main_sizes = Object.fromEntries(
+        pr_files.map(f => [f, size(path.join(MAIN_WORKTREE, f))]));
+
+    generate_report(pr_files, pr_sizes, main_sizes);
+}
+finally {
+    exec(`git worktree remove ${MAIN_WORKTREE}`, { stdio: "inherit" });
+}
diff --git a/.github/workflows/pr-diff-size.yml b/.github/workflows/pr-diff-size.yml
index 691562d..5ebbd61 100644
--- a/.github/workflows/pr-diff-size.yml
+++ b/.github/workflows/pr-diff-size.yml
@@ -27,16 +27,13 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install Dependencies
-        run: npm ci
+        run: npm ci --include=dev
 
-      - name: Build
-        run: npm run build
-        env:
-          NODE_ENV: production
-          SKIP_GIT_TAG_RESOLUTION: true
+      - name: Prepate report path
+        run: echo "SIZE_REPORT_OUTPUT=$RUNNER_TEMP/comment-${{ github.event.pull_request.number }}.md" >> $GITHUB_ENV
 
       - name: Run size comparison
-        run: npm run size-diff-report > comment.md
+        run: npm run size-report
         env:
           NODE_ENV: production
           SKIP_GIT_TAG_RESOLUTION: true
@@ -46,8 +43,8 @@ jobs:
         with:
           script: |
             const fs = require('fs');
-            const body = fs.readFileSync('./comment.md', 'utf8');
-            const pr_number = context.payload.workflow_run.pull_requests[0].number;
+            const body = fs.readFileSync(process.env.SIZE_REPORT_OUTPUT, 'utf8');
+            const pr_number = context.issue.number;
 
             const { data: comments } = await github.rest.issues.listComments({
               owner: context.repo.owner,
diff --git a/package.json b/package.json
index a18dfaa..e3f7e32 100644
--- a/package.json
+++ b/package.json
@@ -25,7 +25,7 @@
   "scripts": {
     "build": "cross-env NODE_ENV=production gulp build",
     "build:debug": "gulp build",
-    "size-diff-report": "node .github/scripts/compare-packages-size.js",
+    "size-report": "cross-env NODE_ENV=production SKIP_GIT_TAG_RESOLUTION=true node .github/scripts/compare-packages-size.js",
     "test": "gulp build && vitest run && playwright test",
     "test:playwright": "playwright test",
     "test:vitest": "vitest run"