diff --git a/.github/workflows/close-unvetted-pr.yml b/.github/workflows/close-unvetted-pr.yml
new file mode 100644
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+++ b/.github/workflows/close-unvetted-pr.yml
@@ -0,0 +1,252 @@
+name: Close Unvetted Non-Maintainer PRs
+
+on:
+  pull_request_target:
+    types: [opened]
+
+jobs:
+  validate-non-maintainer-pr:
+    name: Validate Non-Maintainer PR
+    runs-on: ubuntu-24.04
+    permissions:
+      pull-requests: write
+      contents: write
+    steps:
+      - name: Generate GitHub App token
+        id: app-token
+        uses: actions/create-github-app-token@f8d387b68d61c58ab83c6c016672934102569859  # v2
+        with:
+          app-id: ${{ vars.SDK_MAINTAINER_BOT_APP_ID }}
+          private-key: ${{ secrets.SDK_MAINTAINER_BOT_PRIVATE_KEY }}
+
+      - name: Validate PR
+        uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea  # v7.0.1
+        with:
+          github-token: ${{ steps.app-token.outputs.token }}
+          script: |
+            const pullRequest = context.payload.pull_request;
+            const repo = context.repo;
+            const prAuthor = pullRequest.user.login;
+            const contributingUrl = `https://github.com/${repo.owner}/${repo.repo}/blob/master/CONTRIBUTING.md`;
+
+            // --- Helper: check if a user has admin or maintain permission on a repo (cached) ---
+            const maintainerCache = new Map();
+            async function isMaintainer(owner, repoName, username) {
+              const key = `${owner}/${repoName}:${username}`;
+              if (maintainerCache.has(key)) return maintainerCache.get(key);
+              let result = false;
+              try {
+                const { data } = await github.rest.repos.getCollaboratorPermissionLevel({
+                  owner,
+                  repo: repoName,
+                  username,
+                });
+                // permission field uses legacy values (admin/write/read/none) where
+                // maintain maps to write. Use role_name for the actual role.
+                result = ['admin', 'maintain'].includes(data.role_name);
+              } catch {
+                // noop — result stays false
+              }
+              maintainerCache.set(key, result);
+              return result;
+            }
+
+            // --- Step 1: Check if PR author is a maintainer (admin or maintain role) ---
+            const authorIsMaintainer = await isMaintainer(repo.owner, repo.repo, prAuthor);
+            if (authorIsMaintainer) {
+              core.info(`PR author ${prAuthor} has admin/maintain access. Skipping.`);
+              return;
+            }
+            core.info(`PR author ${prAuthor} is not a maintainer.`);
+
+            // --- Step 2: Parse issue references from PR body ---
+            const body = pullRequest.body || '';
+
+            // Match all issue reference formats:
+            //   #123, Fixes #123, getsentry/repo#123, Fixes getsentry/repo#123
+            //   https://github.com/getsentry/repo/issues/123
+            const issueRefs = [];
+            const seen = new Set();
+
+            // Pattern 1: Full GitHub URLs
+            const urlPattern = /https?:\/\/github\.com\/(getsentry)\/([\w.-]+)\/issues\/(\d+)/gi;
+            for (const match of body.matchAll(urlPattern)) {
+              const key = `${match[1]}/${match[2]}#${match[3]}`;
+              if (!seen.has(key)) {
+                seen.add(key);
+                issueRefs.push({ owner: match[1], repo: match[2], number: parseInt(match[3]) });
+              }
+            }
+
+            // Pattern 2: Cross-repo references (getsentry/repo#123)
+            const crossRepoPattern = /(?:(?:fix|fixes|fixed|close|closes|closed|resolve|resolves|resolved)\s+)?(getsentry)\/([\w.-]+)#(\d+)/gi;
+            for (const match of body.matchAll(crossRepoPattern)) {
+              const key = `${match[1]}/${match[2]}#${match[3]}`;
+              if (!seen.has(key)) {
+                seen.add(key);
+                issueRefs.push({ owner: match[1], repo: match[2], number: parseInt(match[3]) });
+              }
+            }
+
+            // Pattern 3: Same-repo references (#123)
+            // Negative lookbehind to avoid matching cross-repo refs or URLs already captured
+            const sameRepoPattern = /(?:(?:fix|fixes|fixed|close|closes|closed|resolve|resolves|resolved)\s+)?(?<![/\w])#(\d+)/gi;
+            for (const match of body.matchAll(sameRepoPattern)) {
+              const key = `${repo.owner}/${repo.repo}#${match[1]}`;
+              if (!seen.has(key)) {
+                seen.add(key);
+                issueRefs.push({ owner: repo.owner, repo: repo.repo, number: parseInt(match[1]) });
+              }
+            }
+
+            core.info(`Found ${issueRefs.length} issue reference(s): ${[...seen].join(', ')}`);
+
+            // --- Helper: close PR with comment and label ---
+            async function closePR(message) {
+              await github.rest.issues.addLabels({
+                ...repo,
+                issue_number: pullRequest.number,
+                labels: ['violating-contribution-guidelines'],
+              });
+
+              await github.rest.issues.createComment({
+                ...repo,
+                issue_number: pullRequest.number,
+                body: message,
+              });
+
+              await github.rest.pulls.update({
+                ...repo,
+                pull_number: pullRequest.number,
+                state: 'closed',
+              });
+            }
+
+            // --- Step 3: No issue references ---
+            if (issueRefs.length === 0) {
+              core.info('No issue references found. Closing PR.');
+              await closePR([
+                'This PR has been automatically closed. All non-maintainer contributions must reference an existing GitHub issue.',
+                '',
+                '**Next steps:**',
+                '1. Find or open an issue describing the problem or feature',
+                '2. Discuss the approach with a maintainer in the issue',
+                '3. Once a maintainer has acknowledged your proposed approach, open a new PR referencing the issue',
+                '',
+                `Please review our [contributing guidelines](${contributingUrl}) for more details.`,
+              ].join('\n'));
+              return;
+            }
+
+            // --- Step 4: Validate each referenced issue ---
+            // A PR is valid if ANY referenced issue passes all checks.
+            let hasAssigneeConflict = false;
+            let hasNoDiscussion = false;
+
+            for (const ref of issueRefs) {
+              core.info(`Checking issue ${ref.owner}/${ref.repo}#${ref.number}...`);
+
+              let issue;
+              try {
+                const { data } = await github.rest.issues.get({
+                  owner: ref.owner,
+                  repo: ref.repo,
+                  issue_number: ref.number,
+                });
+                issue = data;
+              } catch (e) {
+                core.warning(`Could not fetch issue ${ref.owner}/${ref.repo}#${ref.number}: ${e.message}`);
+                continue;
+              }
+
+              // Check assignee: if assigned to someone other than PR author, flag it
+              if (issue.assignees && issue.assignees.length > 0) {
+                const assignedToAuthor = issue.assignees.some(a => a.login === prAuthor);
+                if (!assignedToAuthor) {
+                  core.info(`Issue ${ref.owner}/${ref.repo}#${ref.number} is assigned to someone else.`);
+                  hasAssigneeConflict = true;
+                  continue;
+                }
+              }
+
+              // Check discussion: both PR author and a maintainer must have commented
+              const comments = await github.paginate(github.rest.issues.listComments, {
+                owner: ref.owner,
+                repo: ref.repo,
+                issue_number: ref.number,
+                per_page: 100,
+              });
+
+              // Also consider the issue author as a participant (opening the issue is a form of discussion)
+              // Guard against null user (deleted/suspended GitHub accounts)
+              const prAuthorParticipated =
+                issue.user?.login === prAuthor ||
+                comments.some(c => c.user?.login === prAuthor);
+
+              let maintainerParticipated = false;
+              if (prAuthorParticipated) {
+                // Check each commenter (and issue author) for admin/maintain access on the issue's repo
+                const usersToCheck = new Set();
+                if (issue.user?.login) usersToCheck.add(issue.user.login);
+                for (const comment of comments) {
+                  if (comment.user?.login && comment.user.login !== prAuthor) {
+                    usersToCheck.add(comment.user.login);
+                  }
+                }
+
+                for (const user of usersToCheck) {
+                  if (user === prAuthor) continue;
+                  if (await isMaintainer(repo.owner, repo.repo, user)) {
+                    maintainerParticipated = true;
+                    core.info(`Maintainer ${user} participated in ${ref.owner}/${ref.repo}#${ref.number}.`);
+                    break;
+                  }
+                }
+              }
+
+              if (prAuthorParticipated && maintainerParticipated) {
+                core.info(`Issue ${ref.owner}/${ref.repo}#${ref.number} has valid discussion. PR is allowed.`);
+                return;  // PR is valid — at least one issue passes all checks
+              }
+
+              core.info(`Issue ${ref.owner}/${ref.repo}#${ref.number} lacks discussion between author and maintainer.`);
+              hasNoDiscussion = true;
+            }
+
+            // --- Step 5: No valid issue found — close with the most relevant reason ---
+            if (hasAssigneeConflict) {
+              core.info('Closing PR: referenced issue is assigned to someone else.');
+              await closePR([
+                'This PR has been automatically closed. The referenced issue is already assigned to someone else.',
+                '',
+                'If you believe this assignment is outdated, please comment on the issue to discuss before opening a new PR.',
+                '',
+                `Please review our [contributing guidelines](${contributingUrl}) for more details.`,
+              ].join('\n'));
+              return;
+            }
+
+            if (hasNoDiscussion) {
+              core.info('Closing PR: no discussion between PR author and a maintainer in the referenced issue.');
+              await closePR([
+                'This PR has been automatically closed. The referenced issue does not show a discussion between you and a maintainer.',
+                '',
+                'To avoid wasted effort on both sides, please discuss your proposed approach in the issue first and wait for a maintainer to respond before opening a PR.',
+                '',
+                `Please review our [contributing guidelines](${contributingUrl}) for more details.`,
+              ].join('\n'));
+              return;
+            }
+
+            // If we get here, all issue refs were unfetchable
+            core.info('Could not validate any referenced issues. Closing PR.');
+            await closePR([
+              'This PR has been automatically closed. The referenced issue(s) could not be found.',
+              '',
+              '**Next steps:**',
+              '1. Ensure the issue exists and is in a `getsentry` repository',
+              '2. Discuss the approach with a maintainer in the issue',
+              '3. Once a maintainer has acknowledged your proposed approach, open a new PR referencing the issue',
+              '',
+              `Please review our [contributing guidelines](${contributingUrl}) for more details.`,
+            ].join('\n'));