diff --git a/.github/workflows/accept-size-increase.yml b/.github/workflows/accept-size-increase.yml
new file mode 100644
index 000000000000..f5b9a910e0f0
--- /dev/null
+++ b/.github/workflows/accept-size-increase.yml
@@ -0,0 +1,101 @@
+name: 'Automation: Accept Bundlesize Increase'
+on:
+  pull_request:
+    types: [labeled]
+
+concurrency:
+  group: accept-size-increase-${{ github.event.pull_request.number }}
+  cancel-in-progress: true
+
+jobs:
+  bump-size-limits:
+    if: github.event.label.name == 'Accept Bundlesize Increase'
+    runs-on: ubuntu-24.04
+    permissions:
+      contents: write
+      pull-requests: write
+      actions: read
+    steps:
+      - name: Generate GitHub App token
+        id: app-token
+        uses: actions/create-github-app-token@v2
+        with:
+          app-id: ${{ vars.GITFLOW_APP_ID }}
+          private-key: ${{ secrets.GITFLOW_APP_PRIVATE_KEY }}
+
+      - uses: actions/checkout@v6
+        with:
+          ref: ${{ github.head_ref }}
+          token: ${{ steps.app-token.outputs.token }}
+
+      - uses: actions/setup-node@v6
+        with:
+          node-version-file: 'package.json'
+
+      - name: Install dependencies
+        run: yarn install --ignore-engines --frozen-lockfile
+
+      - name: Find latest CI run for this PR
+        id: find-run
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          RUN_JSON=$(gh run list \
+            --workflow "CI: Build & Test" \
+            --branch "${{ github.head_ref }}" \
+            --status completed \
+            --limit 1 \
+            --json databaseId,headSha)
+          RUN_ID=$(echo "$RUN_JSON" | jq -r '.[0].databaseId')
+          RUN_SHA=$(echo "$RUN_JSON" | jq -r '.[0].headSha')
+          if [ -z "$RUN_ID" ] || [ "$RUN_ID" = "null" ]; then
+            echo "::error::No completed CI run found. Wait for CI to finish, then re-add the label."
+            exit 1
+          fi
+          HEAD_SHA=$(git rev-parse HEAD)
+          if [ "$RUN_SHA" != "$HEAD_SHA" ]; then
+            echo "::error::CI run ($RUN_SHA) does not match current HEAD ($HEAD_SHA). Wait for the latest CI run to complete, then re-add the label."
+            exit 1
+          fi
+          echo "run_id=$RUN_ID" >> "$GITHUB_OUTPUT"
+
+      - name: Download build artifacts
+        uses: actions/download-artifact@v6
+        with:
+          name: build-output
+          run-id: ${{ steps.find-run.outputs.run_id }}
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Run size-limit and bump failing entries
+        id: bump
+        run: node scripts/bump-size-limits.mjs
+
+      - name: Format
+        run: yarn format
+
+      - name: Commit and push
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+          git add .size-limit.js
+          git diff --cached --quiet && echo "No changes to commit" && exit 0
+          git commit -m "chore: Bump size limits"
+          git push
+
+      - name: Comment on PR
+        if: steps.bump.outputs.summary != ''
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          SUMMARY: ${{ steps.bump.outputs.summary }}
+        run: |
+          echo "$SUMMARY" > /tmp/pr-comment.md
+          gh pr comment "${{ github.event.pull_request.number }}" \
+            --body-file /tmp/pr-comment.md
+
+      - name: Remove label
+        if: always()
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          gh pr edit "${{ github.event.pull_request.number }}" \
+            --remove-label "Accept Bundlesize Increase"
diff --git a/.size-limit.js b/.size-limit.js
index 38a83445d021..84153bd6aa0a 100644
--- a/.size-limit.js
+++ b/.size-limit.js
@@ -178,13 +178,13 @@ module.exports = [
     name: 'CDN Bundle',
     path: createCDNPath('bundle.min.js'),
     gzip: true,
-    limit: '29 KB',
+    limit: '27 KB',
   },
   {
     name: 'CDN Bundle (incl. Tracing)',
     path: createCDNPath('bundle.tracing.min.js'),
     gzip: true,
-    limit: '44 KB',
+    limit: '42 KB',
   },
   {
     name: 'CDN Bundle (incl. Logs, Metrics)',
@@ -283,14 +283,14 @@ module.exports = [
     path: createCDNPath('bundle.tracing.replay.feedback.min.js'),
     gzip: false,
     brotli: false,
-    limit: '264 KB',
+    limit: '263 KB',
   },
   {
     name: 'CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed',
     path: createCDNPath('bundle.tracing.replay.feedback.logs.metrics.min.js'),
     gzip: false,
     brotli: false,
-    limit: '264 KB',
+    limit: '200 KB',
   },
   // Next.js SDK (ESM)
   {
@@ -333,7 +333,7 @@ module.exports = [
     path: 'packages/node/build/esm/index.js',
     import: createImport('initWithoutDefaultIntegrations', 'getDefaultIntegrationsWithoutPerformance'),
     gzip: true,
-    limit: '98 KB',
+    limit: '90 KB',
     ignore: [...builtinModules, ...nodePrefixedBuiltinModules],
     modifyWebpackConfig: function (config) {
       const webpack = require('webpack');
@@ -356,7 +356,7 @@ module.exports = [
     import: createImport('init'),
     ignore: [...builtinModules, ...nodePrefixedBuiltinModules],
     gzip: true,
-    limit: '114 KB',
+    limit: '1 KB',
   },
 ];
 
diff --git a/dev-packages/size-limit-gh-action/index.mjs b/dev-packages/size-limit-gh-action/index.mjs
index 3dac81a3f080..6e80046f9054 100644
--- a/dev-packages/size-limit-gh-action/index.mjs
+++ b/dev-packages/size-limit-gh-action/index.mjs
@@ -182,24 +182,25 @@ async function run() {
 
     if (status > 0) {
       try {
-        const results = limit.parseResults(output);
-        const failedResults = results
-          .filter(result => result.passed || false)
-          .map(result => ({
-            name: result.name,
-            size: +result.size,
-            sizeLimit: +result.sizeLimit,
-          }));
+        const results = JSON.parse(output);
+        const failedResults = results.filter(result => !result.passed);
 
         if (failedResults.length > 0) {
-          // eslint-disable-next-line no-console
-          console.log('Exceeded size-limits:', failedResults);
+          const lines = failedResults.map(r => {
+            const size = (r.size / 1024).toFixed(1);
+            const max = (r.sizeLimit / 1024).toFixed(1);
+            const over = ((r.size - r.sizeLimit) / 1024).toFixed(1);
+            return `  ${r.name}: ${size} KB (limit: ${max} KB, +${over} KB over)`;
+          });
+          core.error(`Size limit exceeded:\n${lines.join('\n')}`);
         }
       } catch {
         // noop
       }
 
-      setFailed('Size limit has been exceeded.');
+      setFailed(
+        'Size limit has been exceeded. To accept this increase, add the "Accept Bundlesize Increase" label to this PR or update `.size-limit.js` manually.',
+      );
     }
   } catch (error) {
     core.error(error);
diff --git a/scripts/bump-size-limits.mjs b/scripts/bump-size-limits.mjs
new file mode 100644
index 000000000000..46a66ef8fc69
--- /dev/null
+++ b/scripts/bump-size-limits.mjs
@@ -0,0 +1,84 @@
+/* oxlint-disable no-console */
+import { execSync } from 'node:child_process';
+import { readFileSync, writeFileSync, appendFileSync } from 'node:fs';
+
+const SIZE_LIMIT_CONFIG = '.size-limit.js';
+
+function roundUpToHalfKB(bytes) {
+  return Math.ceil((bytes / 1024) * 2) / 2;
+}
+
+function run() {
+  let output;
+  try {
+    output = execSync('yarn run --silent size-limit --json', {
+      encoding: 'utf-8',
+      maxBuffer: 10 * 1024 * 1024,
+      // size-limit exits with non-zero when limits are exceeded, which is expected
+      stdio: ['pipe', 'pipe', 'pipe'],
+    });
+  } catch (error) {
+    // size-limit exits with code 1 when limits are exceeded, but still writes JSON to stdout
+    output = error.stdout;
+    if (!output) {
+      console.error('size-limit produced no output.');
+      process.exit(1);
+    }
+  }
+
+  let results;
+  try {
+    results = JSON.parse(output);
+  } catch {
+    console.error('Failed to parse size-limit JSON output.');
+    console.error('Raw output:', output.slice(0, 500));
+    process.exit(1);
+  }
+
+  const failedEntries = results.filter(r => !r.passed);
+
+  if (failedEntries.length === 0) {
+    console.log('All size-limit checks passed. Nothing to bump.');
+    return;
+  }
+
+  console.log(`Found ${failedEntries.length} failing size-limit entries:`);
+
+  let config = readFileSync(SIZE_LIMIT_CONFIG, 'utf-8');
+  const summaryLines = [];
+
+  for (const entry of failedEntries) {
+    const actualSize = entry.size;
+    const margin = Math.min(actualSize * 0.1, 1024);
+    const newLimitKB = roundUpToHalfKB(actualSize + margin);
+    const newLimitStr = `${newLimitKB} KB`;
+
+    const nameEscaped = entry.name.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+    const regex = new RegExp(`(name:\\s*'${nameEscaped}'[\\s\\S]*?limit:\\s*')([^']+)(')`);
+
+    const match = config.match(regex);
+    if (!match) {
+      console.error(`  WARNING: Could not find limit entry for "${entry.name}" in ${SIZE_LIMIT_CONFIG}`);
+      continue;
+    }
+
+    const oldLimitStr = match[2];
+    console.log(`  ${entry.name}: ${oldLimitStr} -> ${newLimitStr}`);
+    summaryLines.push(`- \`${entry.name}\`: ${oldLimitStr} -> ${newLimitStr}`);
+
+    config = config.replace(regex, `$1${newLimitStr}$3`);
+  }
+
+  writeFileSync(SIZE_LIMIT_CONFIG, config, 'utf-8');
+  console.log(`\nUpdated ${SIZE_LIMIT_CONFIG}`);
+
+  // Write summary to $GITHUB_OUTPUT for the PR comment step
+  if (process.env.GITHUB_OUTPUT) {
+    const summary = `Bumped size limits:\n${summaryLines.join('\n')}`;
+    // Multi-line output requires delimiter syntax
+    const delimiter = `EOF_${Date.now()}`;
+    appendFileSync(process.env.GITHUB_OUTPUT, `summary<<${delimiter}\n${summary}\n${delimiter}\n`);
+  }
+}
+
+run();