diff --git a/.github/workflows/pr-template-format.yml b/.github/workflows/pr-template-format.yml
new file mode 100644
index 000000000..33fd2d325
--- /dev/null
+++ b/.github/workflows/pr-template-format.yml
@@ -0,0 +1,105 @@
+name: PR Template Format
+
+on:
+  pull_request_target:
+    types: [opened, edited, reopened, synchronize, ready_for_review]
+
+permissions:
+  contents: read
+  issues: write
+  pull-requests: write
+
+jobs:
+  check-template-format:
+    name: Pull request template format
+    runs-on: ubuntu-latest
+    timeout-minutes: 2
+    steps:
+      - name: Check out policy from base branch
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6.0.2
+
+      - name: Evaluate PR template format
+        id: policy
+        env:
+          PR_BODY: ${{ github.event.pull_request.body }}
+          AUTHOR_ASSOCIATION: ${{ github.event.pull_request.author_association }}
+        run: node scripts/pr-template-policy.cjs
+
+      - name: Warn trusted contributor about missing template
+        if: steps.policy.outputs.action == 'warn'
+        uses: actions/github-script@d746ffe35508b1917358783b479e04febd2b8f71 # v9.0.0
+        with:
+          script: |
+            const marker = '<!-- gsd-pr-template-policy -->';
+            const pr = context.payload.pull_request;
+            const policy = JSON.parse(${{ toJSON(steps.policy.outputs.result) }});
+            const comments = await github.paginate(github.rest.issues.listComments, {
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: pr.number,
+              per_page: 100,
+            });
+            if (!comments.some((comment) => comment.body && comment.body.includes(marker))) {
+              await github.rest.issues.createComment({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                issue_number: pr.number,
+                body: [
+                  marker,
+                  '## Please use the PR template format',
+                  '',
+                  'This PR is allowed to stay open because the author is a contributor or higher, but the body does not follow one of the required PR templates.',
+                  '',
+                  'Please update the PR description to use the fix, enhancement, or feature template format from `CONTRIBUTING.md` so the automated documentation modules can do their job.',
+                  '',
+                  `Detected problem: ${policy.reason}`,
+                ].join('\n'),
+              });
+            }
+            core.warning(policy.reason);
+
+      - name: Comment, close, and fail untrusted malformed PR
+        if: steps.policy.outputs.action == 'close'
+        uses: actions/github-script@d746ffe35508b1917358783b479e04febd2b8f71 # v9.0.0
+        with:
+          script: |
+            const marker = '<!-- gsd-pr-template-policy -->';
+            const pr = context.payload.pull_request;
+            const repoUrl = `https://github.com/${context.repo.owner}/${context.repo.repo}`;
+            const policy = JSON.parse(${{ toJSON(steps.policy.outputs.result) }});
+            const comments = await github.paginate(github.rest.issues.listComments, {
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: pr.number,
+              per_page: 100,
+            });
+            if (!comments.some((comment) => comment.body && comment.body.includes(marker))) {
+              await github.rest.issues.createComment({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                issue_number: pr.number,
+                body: [
+                  marker,
+                  '## PR template required - PR auto-closed',
+                  '',
+                  'This PR does not follow one of the required pull request templates from the contribution guidelines.',
+                  '',
+                  'Please reopen with the correct typed template:',
+                  '',
+                  `- [Fix PR template](${repoUrl}/blob/main/.github/PULL_REQUEST_TEMPLATE/fix.md)`,
+                  `- [Enhancement PR template](${repoUrl}/blob/main/.github/PULL_REQUEST_TEMPLATE/enhancement.md)`,
+                  `- [Feature PR template](${repoUrl}/blob/main/.github/PULL_REQUEST_TEMPLATE/feature.md)`,
+                  '',
+                  'This check only validates template format. It does not close PRs for an unfilled issue number such as `Fixes #`; the issue-link workflow handles issue references separately after the PR exists.',
+                  '',
+                  `Detected problem: ${policy.reason}`,
+                ].join('\n'),
+              });
+            }
+            await github.rest.pulls.update({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              pull_number: pr.number,
+              state: 'closed',
+            });
+            core.setFailed(policy.reason);
diff --git a/scripts/pr-template-policy.cjs b/scripts/pr-template-policy.cjs
new file mode 100644
index 000000000..f8dcc5455
--- /dev/null
+++ b/scripts/pr-template-policy.cjs
@@ -0,0 +1,167 @@
+#!/usr/bin/env node
+
+const TRUSTED_AUTHOR_ASSOCIATIONS = new Set([
+  'CONTRIBUTOR',
+  'COLLABORATOR',
+  'MEMBER',
+  'OWNER',
+]);
+
+const DEFAULT_TEMPLATE_MARKERS = [
+  'Wrong template',
+  'Every PR must use a typed template',
+  'Select the template that matches your PR',
+];
+
+const TEMPLATES = [
+  {
+    name: 'fix',
+    heading: 'Fix PR',
+    requiredHeadings: [
+      'Fix PR',
+      'Linked Issue',
+      'What was broken',
+      'What this fix does',
+      'Testing',
+      'Checklist',
+    ],
+  },
+  {
+    name: 'enhancement',
+    heading: 'Enhancement PR',
+    requiredHeadings: [
+      'Enhancement PR',
+      'Linked Issue',
+      'What this enhancement improves',
+      'Before / After',
+      'How it was implemented',
+      'Testing',
+      'Scope confirmation',
+      'Checklist',
+    ],
+  },
+  {
+    name: 'feature',
+    heading: 'Feature PR',
+    requiredHeadings: [
+      'Feature PR',
+      'Linked Issue',
+      'Feature summary',
+      'What changed',
+      'Implementation notes',
+      'Spec compliance',
+      'Testing',
+      'Scope confirmation',
+      'Checklist',
+    ],
+  },
+];
+
+function stripMarkdownDecoration(value) {
+  return value
+    .replace(/^\s*#+\s*/, '')
+    .replace(/\s*#+\s*$/, '')
+    .replace(/\*\*/g, '')
+    .trim()
+    .toLowerCase();
+}
+
+function extractHeadings(body) {
+  const headings = new Set();
+  for (const line of String(body || '').split(/\r?\n/)) {
+    if (/^\s*#{1,6}\s+\S/.test(line)) {
+      headings.add(stripMarkdownDecoration(line));
+    }
+  }
+  return headings;
+}
+
+function includesDefaultTemplate(body) {
+  const text = String(body || '').toLowerCase();
+  return DEFAULT_TEMPLATE_MARKERS.some((marker) => text.includes(marker.toLowerCase()));
+}
+
+function matchingTemplate(body) {
+  const headings = extractHeadings(body);
+  for (const template of TEMPLATES) {
+    if (!headings.has(stripMarkdownDecoration(template.heading))) continue;
+    const missingHeadings = template.requiredHeadings.filter((heading) => {
+      return !headings.has(stripMarkdownDecoration(heading));
+    });
+    return {
+      template: template.name,
+      missingHeadings,
+    };
+  }
+  return {
+    template: null,
+    missingHeadings: [],
+  };
+}
+
+function evaluatePrTemplate(body, authorAssociation) {
+  const association = String(authorAssociation || '').toUpperCase();
+  const trusted = TRUSTED_AUTHOR_ASSOCIATIONS.has(association);
+  const normalizedBody = String(body || '').trim();
+
+  let valid = true;
+  let reason = 'PR body uses a typed pull request template.';
+  let template = null;
+  let missingHeadings = [];
+
+  if (!normalizedBody) {
+    valid = false;
+    reason = 'PR body is empty; a typed pull request template is required.';
+  } else if (includesDefaultTemplate(normalizedBody)) {
+    valid = false;
+    reason = 'PR body still contains the default wrong-template guidance.';
+  } else {
+    const match = matchingTemplate(normalizedBody);
+    template = match.template;
+    missingHeadings = match.missingHeadings;
+    if (!template) {
+      valid = false;
+      reason = 'PR body does not match the fix, enhancement, or feature template.';
+    } else if (missingHeadings.length > 0) {
+      valid = false;
+      reason = `PR body appears to use the ${template} template but is missing required headings.`;
+    }
+  }
+
+  let action = 'pass';
+  if (!valid) {
+    action = trusted ? 'warn' : 'close';
+  }
+
+  return {
+    valid,
+    action,
+    trusted,
+    authorAssociation: association || 'UNKNOWN',
+    template,
+    reason,
+    missingHeadings,
+  };
+}
+
+function main() {
+  const result = evaluatePrTemplate(process.env.PR_BODY || '', process.env.AUTHOR_ASSOCIATION || '');
+  process.stdout.write(`${JSON.stringify(result)}\n`);
+  if (process.env.GITHUB_OUTPUT) {
+    const fs = require('fs');
+    fs.appendFileSync(process.env.GITHUB_OUTPUT, `result=${JSON.stringify(result)}\n`);
+    fs.appendFileSync(process.env.GITHUB_OUTPUT, `action=${result.action}\n`);
+    fs.appendFileSync(process.env.GITHUB_OUTPUT, `valid=${result.valid ? 'true' : 'false'}\n`);
+  }
+}
+
+if (require.main === module) {
+  main();
+}
+
+module.exports = {
+  evaluatePrTemplate,
+  extractHeadings,
+  includesDefaultTemplate,
+  matchingTemplate,
+};
diff --git a/tests/pr-template-policy.test.cjs b/tests/pr-template-policy.test.cjs
new file mode 100644
index 000000000..e5c818c3d
--- /dev/null
+++ b/tests/pr-template-policy.test.cjs
@@ -0,0 +1,174 @@
+const { describe, test } = require('node:test');
+const assert = require('node:assert/strict');
+
+const { evaluatePrTemplate } = require('../scripts/pr-template-policy.cjs');
+
+const fixBody = [
+  '## Fix PR',
+  '',
+  '## Linked Issue',
+  'Fixes #123',
+  '',
+  '## What was broken',
+  'The thing was broken.',
+  '',
+  '## What this fix does',
+  'The thing now works.',
+  '',
+  '## Root cause',
+  'A missing guard.',
+  '',
+  '## Testing',
+  'node --test tests/example.test.cjs',
+  '',
+  '## Checklist',
+  '- [x] Issue linked above with `Fixes #NNN`',
+].join('\n');
+
+const enhancementBody = [
+  '## Enhancement PR',
+  '',
+  '## Linked Issue',
+  'Closes #123',
+  '',
+  '## What this enhancement improves',
+  'Existing output.',
+  '',
+  '## Before / After',
+  '**Before:** noisy',
+  '**After:** clear',
+  '',
+  '## How it was implemented',
+  'Small refactor.',
+  '',
+  '## Testing',
+  'node --test tests/example.test.cjs',
+  '',
+  '## Scope confirmation',
+  '- [x] Matches approved issue.',
+  '',
+  '## Checklist',
+  '- [x] Tests pass',
+].join('\n');
+
+const featureBody = [
+  '## Feature PR',
+  '',
+  '## Linked Issue',
+  'Closes #123',
+  '',
+  '## Feature summary',
+  'Adds a new thing.',
+  '',
+  '## What changed',
+  '### New files',
+  'None.',
+  '### Modified files',
+  'One file.',
+  '',
+  '## Implementation notes',
+  'Implemented as approved.',
+  '',
+  '## Spec compliance',
+  '- [x] Criterion met',
+  '',
+  '## Testing',
+  'node --test tests/example.test.cjs',
+  '',
+  '## Scope confirmation',
+  '- [x] Exact scope.',
+  '',
+  '## Checklist',
+  '- [x] Tests pass',
+].join('\n');
+
+describe('pr-template-policy', () => {
+  test('passes PR bodies that use the fix template', () => {
+    const result = evaluatePrTemplate(fixBody, 'NONE');
+
+    assert.equal(result.valid, true);
+    assert.equal(result.action, 'pass');
+    assert.equal(result.template, 'fix');
+  });
+
+  test('passes PR bodies that use the enhancement template', () => {
+    const result = evaluatePrTemplate(enhancementBody, 'FIRST_TIMER');
+
+    assert.equal(result.valid, true);
+    assert.equal(result.action, 'pass');
+    assert.equal(result.template, 'enhancement');
+  });
+
+  test('passes PR bodies that use the feature template', () => {
+    const result = evaluatePrTemplate(featureBody, 'FIRST_TIME_CONTRIBUTOR');
+
+    assert.equal(result.valid, true);
+    assert.equal(result.action, 'pass');
+    assert.equal(result.template, 'feature');
+  });
+
+  test('closes first-time PRs that keep the default template', () => {
+    const result = evaluatePrTemplate([
+      '## Wrong template - please use the correct one for your PR type',
+      '',
+      'Every PR must use a typed template.',
+    ].join('\n'), 'FIRST_TIMER');
+
+    assert.equal(result.valid, false);
+    assert.equal(result.action, 'close');
+    assert.equal(result.trusted, false);
+    assert.match(result.reason, /default wrong-template guidance/);
+  });
+
+  test('warns contributors instead of closing when the template is missing', () => {
+    const result = evaluatePrTemplate('This is a free-form PR body.', 'CONTRIBUTOR');
+
+    assert.equal(result.valid, false);
+    assert.equal(result.action, 'warn');
+    assert.equal(result.trusted, true);
+  });
+
+  test('warns collaborators, members, and owners instead of closing', () => {
+    for (const association of ['COLLABORATOR', 'MEMBER', 'OWNER']) {
+      const result = evaluatePrTemplate('This is a free-form PR body.', association);
+
+      assert.equal(result.valid, false);
+      assert.equal(result.action, 'warn');
+      assert.equal(result.trusted, true);
+    }
+  });
+
+  test('does not close for an unfilled issue slug when the template is present', () => {
+    const body = fixBody.replace('Fixes #123', 'Fixes #');
+    const result = evaluatePrTemplate(body, 'FIRST_TIMER');
+
+    assert.equal(result.valid, true);
+    assert.equal(result.action, 'pass');
+    assert.equal(result.template, 'fix');
+  });
+
+  test('closes first-time PRs that remove required template sections', () => {
+    const result = evaluatePrTemplate(fixBody.replace('## What was broken', '## Background'), 'NONE');
+
+    assert.equal(result.valid, false);
+    assert.equal(result.action, 'close');
+    assert.deepEqual(result.missingHeadings, ['What was broken']);
+  });
+
+  test('closes first-time PRs with empty body', () => {
+    const result = evaluatePrTemplate('', 'FIRST_TIMER');
+
+    assert.equal(result.valid, false);
+    assert.equal(result.action, 'close');
+    assert.match(result.reason, /PR body is empty; a typed pull request template is required\./);
+  });
+
+  test('warns trusted contributors with empty body', () => {
+    const result = evaluatePrTemplate('', 'CONTRIBUTOR');
+
+    assert.equal(result.valid, false);
+    assert.equal(result.action, 'warn');
+    assert.equal(result.trusted, true);
+    assert.match(result.reason, /PR body is empty; a typed pull request template is required\./);
+  });
+});