diff --git a/static/js/admin.js b/static/js/admin.js
index 201f63772..9c7a1ea32 100644
--- a/static/js/admin.js
+++ b/static/js/admin.js
@@ -955,6 +955,8 @@ function renderFeatherlessPanel(panel, ep, row) {
 
 // ChatGPT per-endpoint usage panel expanded state persistence.
 // Preserves only endpoint/auth identifiers, never tokens, secrets, or labels.
+// providerAuthSessionId is ProviderAuthSession.id, independently UUID-generated
+// by routes/chatgpt_subscription_routes.py, not an OAuth token or account ID.
 const CHATGPT_USAGE_EXPANDED_KEY = 'odysseus-chatgpt-usage-expanded';
 
 function _loadExpandedUsageEndpoints() {
@@ -976,23 +978,23 @@ function _saveExpandedUsageEndpoints(set) {
   } catch (_) {}
 }
 
-function _isChatgptUsageExpanded(endpointId, authId) {
+function _isChatgptUsageExpanded(endpointId, providerAuthSessionId) {
   const set = _loadExpandedUsageEndpoints();
   if (endpointId != null && set.has(String(endpointId))) return true;
-  if (authId != null && set.has(String(authId))) return true;
+  if (providerAuthSessionId != null && set.has(String(providerAuthSessionId))) return true;
   return false;
 }
 
-function _setChatgptUsageExpanded(endpointId, authId, expanded) {
+function _setChatgptUsageExpanded(endpointId, providerAuthSessionId, expanded) {
   const set = _loadExpandedUsageEndpoints();
   const epKey = endpointId != null ? String(endpointId) : null;
-  const authKey = authId != null ? String(authId) : null;
+  const providerAuthSessionRowId = providerAuthSessionId != null ? String(providerAuthSessionId) : null;
   if (expanded) {
     if (epKey) set.add(epKey);
-    if (authKey) set.add(authKey);
+    if (providerAuthSessionRowId) set.add(providerAuthSessionRowId);
   } else {
     if (epKey) set.delete(epKey);
-    if (authKey) set.delete(authKey);
+    if (providerAuthSessionRowId) set.delete(providerAuthSessionRowId);
   }
   _saveExpandedUsageEndpoints(set);
 }
diff --git a/static/js/emailLibrary/menus.js b/static/js/emailLibrary/menus.js
index 78a5cc32f..da859ecad 100644
--- a/static/js/emailLibrary/menus.js
+++ b/static/js/emailLibrary/menus.js
@@ -298,8 +298,17 @@ export function _showReaderMoreMenu(em, card, reader, anchor, data) {
     }
     const item = document.createElement('div');
     item.className = 'dropdown-item-compact' + (a.danger ? ' dropdown-item-danger' : '');
-    const arrow = a.submenu ? '<span style="margin-left:auto;opacity:0.5;">›</span>' : '';
-    item.innerHTML = _icon(a.icon) + `<span>${a.label}</span>${arrow}`;
+    // Icons come from repository-owned SVGs in this menu or reader buttons.
+    item.innerHTML = _icon(a.icon);
+    const label = document.createElement('span');
+    label.textContent = a.label;
+    item.appendChild(label);
+    if (a.submenu) {
+      const arrow = document.createElement('span');
+      arrow.style.cssText = 'margin-left:auto;opacity:0.5;';
+      arrow.textContent = '›';
+      item.appendChild(arrow);
+    }
     item.addEventListener('click', (e) => {
       e.stopPropagation();
       if (a.submenu === 'remind') {
diff --git a/static/js/markdown.js b/static/js/markdown.js
index 6b6be2868..cabb624b3 100644
--- a/static/js/markdown.js
+++ b/static/js/markdown.js
@@ -791,8 +791,13 @@ function renderSvgSandbox(source) {
   const height = viewBox ? Number(viewBox[2]) : 9;
   const ratio = Number.isFinite(width / height) && width > 0 && height > 0
     ? Math.max(0.5, Math.min(3, width / height)) : (16 / 9);
-  const titleMatch = cleaned.match(/<title(?:\s[^>]*)?>([\s\S]*?)<\/title>/i);
-  const title = (titleMatch?.[1] || 'Visual explanation').replace(/<[^>]*>/g, '').trim();
+  // Parse in an inert template: nested/malformed SVG title markup stays text.
+  let title = 'Visual explanation';
+  if (typeof document !== 'undefined') {
+    const template = document.createElement('template');
+    template.innerHTML = cleaned;
+    title = template.content.querySelector?.('svg title')?.textContent?.trim() || title;
+  }
   const csp = "default-src 'none'; img-src 'none'; media-src 'none'; font-src 'none'; style-src 'unsafe-inline'";
   const srcdoc = `<!doctype html><html><head><meta charset="utf-8"><meta name="viewport" content="width=device-width,initial-scale=1"><meta http-equiv="Content-Security-Policy" content="${csp}"><style>:root{${svgThemeCss()}}html,body{margin:0;min-height:100%;background:var(--bg);color:var(--fg);overflow:hidden}body{display:grid;place-items:center}svg{display:block;width:100%;height:100%;max-width:100%;background:var(--bg);color:var(--fg)}</style></head><body>${cleaned}</body></html>`;
   return `<figure class="chat-svg-visual"><iframe class="chat-svg-preview" sandbox="" referrerpolicy="no-referrer" loading="lazy" title="${escapeHtml(title)}" style="aspect-ratio:${ratio}" srcdoc="${escapeHtml(srcdoc)}"></iframe></figure>`;
diff --git a/tests/codeql_security_browser.cjs b/tests/codeql_security_browser.cjs
new file mode 100644
index 000000000..a7d6854c1
--- /dev/null
+++ b/tests/codeql_security_browser.cjs
@@ -0,0 +1,185 @@
+const { chromium } = require('playwright');
+const { readFileSync } = require('node:fs');
+const assert = require('node:assert/strict');
+const { extractThemeBootstrap } = require('./helpers/theme_bootstrap.cjs');
+
+(async () => {
+  const origin = process.env.ODYSSEUS_TEST_STATIC_ORIGIN;
+  const browser = await chromium.launch({ headless: true });
+  try {
+    const page = await browser.newPage();
+    const errors = [];
+    const svgRequests = [];
+    const svgFailures = [];
+    page.on('pageerror', error => errors.push(error.message));
+    page.on('request', request => { if (request.url().includes('example.invalid/security-probe')) svgRequests.push(request.url()); });
+    page.on('requestfailed', request => { if (request.url().includes('example.invalid/security-probe')) svgFailures.push(request.failure().errorText); });
+    await page.route('**/security-harness', route => route.fulfill({ contentType: 'text/html', body:
+      '<!doctype html><div id="toast"></div><div id="sidebar"></div><div id="chat-container"></div><div id="chat-history"></div><div id="adm-epList-local"></div><div id="adm-epList-api"></div>' }));
+    const secrets = { access_token: 'ACCESS-SENTINEL', refresh_token: 'REFRESH-SENTINEL', api_key: 'KEY-SENTINEL', password: 'PASSWORD-SENTINEL' };
+    const endpoints = ['a', 'b'].map(id => ({ id: 'endpoint-' + id, provider_auth_id: 'session-' + id,
+      provider: 'chatgpt-subscription', name: 'ChatGPT · LABEL-SENTINEL', category: 'api',
+      base_url: 'https://chatgpt.com/backend-api/codex', is_enabled: true, online: true, models: [], ...secrets }));
+    await page.route('**/api/**', route => {
+      const url = new URL(route.request().url());
+      if (url.pathname === '/api/model-endpoints') return route.fulfill({ json: endpoints });
+      if (url.pathname.endsWith('/usage')) return route.fulfill({ json: { available: true, usage: { limits: [] }, ...secrets } });
+      if (url.pathname.includes('/device/')) return route.fulfill({ status: 400, json: { detail: 'Fixture declines device flow' } });
+      return route.fulfill({ json: { fonts: {}, value: null, tools: [], models: [] } });
+    });
+    // Expose the real internal loader only in this served test copy.
+    await page.route('**/static/js/admin-codeql-harness.js', route => route.fulfill({ contentType: 'application/javascript',
+      body: readFileSync('static/js/admin.js', 'utf8') + '\nexport { loadEndpoints };\n' }));
+    await page.goto(origin + '/security-harness');
+
+    const rendered = await page.evaluate(async () => {
+      const { addMessage } = await import('/static/js/chatRenderer.js');
+      const markdown = await import('/static/js/markdown.js');
+      window.executed = 0;
+      const payloads = [
+        '<img src=x onerror="window.executed++">',
+        '<svg onload="parent.executed++"><script>parent.executed++</script></svg>',
+        '<script>window.executed++</script>',
+        '\"\'><img src=x onerror="window.executed++"> & <angle>',
+        '<details><summary>Nested</summary><img src=x onerror="window.executed++"><a href="javascript:window.executed++">link</a><svg onload="window.executed++"></svg></details>',
+        '<think><img src=x onerror="window.executed++"></think>**Valid** instruction',
+      ];
+      const results = [];
+      for (const payload of payloads) {
+        const message = addMessage('user', 'In the document, edit this specific text (line 1):\n```\nselected\n```\n\nInstruction: ' + payload);
+        if (!message) throw new Error('addMessage failed');
+        const body = message.querySelector('.body');
+        results.push({ tag: body.querySelector('.doc-edit-tag')?.dataset.docEditRef,
+          unsafe: body.querySelectorAll('script, svg[onload], [onerror], [onload], a[href^="javascript:"]').length });
+        const direct = document.createElement('div');
+        direct.innerHTML = markdown.processWithThinking(payload);
+        results.push({ unsafe: direct.querySelectorAll('script, [onerror], [onload], a[href^="javascript:"]').length });
+        message.remove();
+      }
+      const valid = addMessage('user', 'In the document, edit this specific text (lines 1–2):\n```\nselected\n```\n\nInstruction: **Keep bold** and `code`');
+      const titles = [
+        { source: '<svg><title>Nested <b>bold</b> &amp; text</title></svg>', title: 'Nested bold & text' },
+        { source: '<svg><title>\" onload=\"parent.executed++ &lt;script&gt;</title></svg>', title: '\" onload=\"parent.executed++ <script>' },
+        { source: '<svg><title>Malformed <b>nested</title ></svg>', title: 'Malformed nested' },
+        { source: '<svg><title> </title></svg>', title: 'Visual explanation' },
+        { source: '<svg><text>No title</text></svg>', title: 'Visual explanation' },
+      ].map(({ source, title }) => {
+        const host = document.createElement('div');
+        host.innerHTML = markdown.mdToHtml('```svg\n' + source + '\n```');
+        const frame = host.querySelector('iframe');
+        return { expected: title, actual: frame.title, sandbox: frame.getAttribute('sandbox'),
+          referrer: frame.referrerPolicy, onload: frame.hasAttribute('onload'),
+          csp: new DOMParser().parseFromString(frame.srcdoc, 'text/html').querySelector('meta[http-equiv="Content-Security-Policy"]').content };
+      });
+      const svgHost = document.createElement('div');
+      svgHost.innerHTML = markdown.mdToHtml('```svg\n<svg onload="parent.executed++"><title>Attack</title><script>parent.executed++</script><image href="https://example.invalid/security-probe"/></svg>\n```');
+      document.body.appendChild(svgHost);
+      const directValid = document.createElement('div');
+      directValid.innerHTML = markdown.processWithThinking('**Keep bold** and `code`');
+      return { results, titles, instruction: valid.querySelector('.body').textContent,
+        bold: directValid.querySelector('strong')?.textContent, code: directValid.querySelector('code')?.textContent };
+    });
+    assert(rendered.results.every(result => result.unsafe === 0));
+    assert(rendered.results.filter((result, index) => index % 2 === 0).every(result => result.tag === 'line 1'));
+    assert(rendered.instruction.includes('Keep bold and code'));
+    assert.equal(rendered.bold, 'Keep bold');
+    assert.equal(rendered.code, 'code');
+    for (const title of rendered.titles) {
+      assert.equal(title.actual, title.expected);
+      assert.equal(title.sandbox, '');
+      assert.equal(title.referrer, 'no-referrer');
+      assert.equal(title.onload, false);
+      assert.equal(title.csp, "default-src 'none'; img-src 'none'; media-src 'none'; font-src 'none'; style-src 'unsafe-inline'");
+    }
+
+    const menus = await page.evaluate(async () => {
+      const { _showReaderMoreMenu } = await import('/static/js/emailLibrary/menus.js');
+      const { _safeRenderEmailBody } = await import('/static/js/emailLibrary/bodyRender.js');
+      const reader = document.createElement('div');
+      const anchor = document.createElement('button');
+      document.body.append(reader, anchor);
+      const labels = ['<img src=x onerror="window.executed++">', '<svg onload="window.executed++">', '<script>window.executed++</script>', '\" & <angle>', '<b><i>nested</i></b>'];
+      let clicks = 0;
+      for (const [index, label] of labels.entries()) {
+        const button = document.createElement('button');
+        button.className = 'reader-action-overflowed';
+        button.innerHTML = '<svg viewBox="0 0 24 24"><path d="M1 1h2"/></svg>';
+        if (index === 0) button.title = label;
+        else {
+          const span = document.createElement('span');
+          span.className = 'reader-btn-label';
+          span.textContent = label;
+          button.appendChild(span);
+        }
+        button.addEventListener('click', () => clicks++);
+        reader.appendChild(button);
+      }
+      // A remote HTML body can preserve action-like CSS classes and escaped
+      // label text, even though the email sanitizer removes its SVG/handlers.
+      const remoteLabel = '<img src=x onerror="window.executed++">';
+      const remoteBody = document.createElement('div');
+      remoteBody.className = 'email-reader-body';
+      remoteBody.innerHTML = _safeRenderEmailBody({ body_html:
+        '<button class="reader-action-overflowed"><svg onload="window.executed++"></svg><span class="reader-btn-label">&lt;img src=x onerror=&quot;window.executed++&quot;&gt;</span></button>' });
+      if (!remoteBody.querySelector('.reader-action-overflowed')) throw new Error('Remote label fixture was lost');
+      if (remoteBody.querySelector('svg, [onload], [onerror]')) throw new Error('Email body sanitizer failed');
+      reader.appendChild(remoteBody);
+      labels.push(remoteLabel);
+      _showReaderMoreMenu({ uid: 'fixture' }, document.createElement('div'), reader, anchor, {});
+      const menu = document.querySelector('.email-card-dropdown');
+      const items = [...menu.querySelectorAll('.dropdown-item-compact')].slice(0, labels.length);
+      items[0].click();
+      return { labels, actual: items.map(item => item.children[1].textContent), clicks,
+        icons: items.slice(0, -1).every(item => item.querySelector('.dropdown-icon svg path')),
+        remoteIconRemoved: !items.at(-1).querySelector('svg'),
+        arrows: [...menu.querySelectorAll('.dropdown-item-compact')].filter(item => item.lastChild.textContent === '›').length,
+        unsafe: menu.querySelectorAll('script, img, [onload], [onerror]').length };
+    });
+    assert.deepEqual(menus.actual, menus.labels);
+    assert.equal(menus.clicks, 1);
+    assert.equal(menus.icons, true);
+    assert.equal(menus.remoteIconRemoved, true);
+    assert(menus.arrows >= 2);
+    assert.equal(menus.unsafe, 0);
+
+    await page.evaluate(async () => {
+      localStorage.removeItem('odysseus-chatgpt-usage-expanded');
+      window.adminTest = await import('/static/js/admin-codeql-harness.js');
+      await window.adminTest.loadEndpoints();
+    });
+    const toggle = id => page.locator(`[data-adm-chatgpt-usage-toggle="session-${id}"]`);
+    const stored = () => page.evaluate(() => JSON.parse(localStorage.getItem('odysseus-chatgpt-usage-expanded') || '[]').sort());
+    assert.deepEqual(await stored(), []);
+    await toggle('a').click();
+    assert.deepEqual(await stored(), ['endpoint-a', 'session-a']);
+    assert.equal(await toggle('a').getAttribute('aria-expanded'), 'true');
+    assert.equal(await toggle('b').getAttribute('aria-expanded'), 'false');
+    await page.evaluate(() => window.adminTest.loadEndpoints());
+    assert.equal(await toggle('a').getAttribute('aria-expanded'), 'true');
+    await toggle('a').click();
+    assert.deepEqual(await stored(), []);
+    await page.locator('.adm-chatgpt-controls [data-adm-chatgpt-reconnect="session-b"]').click();
+    assert.deepEqual(await stored(), ['endpoint-b', 'session-b']);
+    const storageText = JSON.stringify(await stored());
+    for (const secret of [...Object.values(secrets), 'LABEL-SENTINEL']) assert(!storageText.includes(secret));
+
+    const code = '/* Apply font early */ window.executed++';
+    const fixtures = [
+      `<SCRIPT>${code}</SCRIPT >`,
+      `<script data-note=">">${code}</script\t>`,
+      `<!-- <script>${code}</script> --><script src="external.js">${code}</script><script>${code}</script>`,
+    ];
+    for (const html of fixtures) assert.equal(await page.evaluate(extractThemeBootstrap, html), code);
+    await assert.rejects(page.evaluate(extractThemeBootstrap, `<script>${code}</script><script>${code}</script>`), /found 2/);
+    await assert.rejects(page.evaluate(extractThemeBootstrap, '<script>unrelated</script>'), /found 0/);
+    assert.equal(await page.evaluate(() => window.executed), 0);
+    // Chromium reports a request event even when CSP prevents network access.
+    assert(svgRequests.length > 0);
+    assert.equal(svgFailures.length, svgRequests.length);
+    assert(svgFailures.every(reason => reason === 'csp'));
+    assert.deepEqual(errors, []);
+    console.log(JSON.stringify({ chat: true, markdown: true, svg: true, menus: true, admin: true, bootstrap: true }));
+  } finally {
+    await browser.close();
+  }
+})().catch(error => { console.error(error); process.exit(1); });
diff --git a/tests/css_snapshot/capture.mjs b/tests/css_snapshot/capture.mjs
index 1e8e88c4d..d57865fab 100644
--- a/tests/css_snapshot/capture.mjs
+++ b/tests/css_snapshot/capture.mjs
@@ -7,8 +7,8 @@
 //
 // Determinism rules that matter here, because the digest is only useful if an
 // unchanged stylesheet always produces the same bytes:
-//   - every <script> is stripped from the document, so the DOM stays exactly
-//     what the server sends and no app module can mutate classes underneath us;
+//   - active script elements are removed and script execution is blocked, so
+//     no app module can mutate the served shell's classes underneath us;
 //   - the theme/density classes are injected into the <html> tag *before* the
 //     first paint instead of toggled afterwards, so no CSS transition is ever
 //     mid-interpolation while getComputedStyle runs;
@@ -227,6 +227,9 @@ async function main() {
   const missing = {};
 
   try {
+    // Keep parsing separate from the page whose navigation is intercepted.
+    const parser = await browser.newPage();
+    await parser.route('**/*', route => route.abort());
     let swapped = 0;
     for (const page of job.pages) {
       snapshot[page.name] = {};
@@ -280,7 +283,14 @@ async function main() {
         await tab.route(`**${documentPath}`, async route => {
           const response = await route.fetch();
           let html = await response.text();
-          html = html.replace(/<script\b[^>]*>[\s\S]*?<\/script>/gi, '');
+          // Browser parsing handles HTML/SVG scripts and unusual end tags.
+          // The parsed document is inert; only the script-free shell is served.
+          html = await parser.evaluate(source => {
+            const doc = new DOMParser().parseFromString(source, 'text/html');
+            doc.querySelectorAll('script').forEach(script => script.remove());
+            const doctype = doc.doctype ? new XMLSerializer().serializeToString(doc.doctype) : '';
+            return doctype + doc.documentElement.outerHTML;
+          }, html);
           // Focus states are outside this idle-state inventory. Autofocus can
           // run after load, racing the measurement and changing outline-offset.
           html = html.replace(/(<[^>]*?)\sautofocus(?=[\s=>])(?:\s*=\s*(?:"[^"]*"|'[^']*'|[^\s>]+))?/gi, '$1');
@@ -291,7 +301,13 @@ async function main() {
           const classes = [variant.theme === 'light' ? 'light' : '', variant.density && variant.density !== 'comfortable' ? `density-${variant.density}` : '']
             .filter(Boolean).join(' ');
           html = html.replace(/<html\b([^>]*)>/i, (match, attrs) => `<html${attrs.replace(/\sclass="[^"]*"/i, '')} class="${classes}">`);
-          await route.fulfill({ response, body: html, headers: { ...response.headers(), 'content-type': 'text/html; charset=utf-8' } });
+          const headers = response.headers();
+          // Also deny handlers or scripts exposed by serialization/re-parsing.
+          // Playwright evaluation still runs the CSS measurement functions.
+          const scriptPolicy = "script-src 'none'";
+          headers['content-security-policy'] = headers['content-security-policy']
+            ? `${headers['content-security-policy']}, ${scriptPolicy}` : scriptPolicy;
+          await route.fulfill({ response, body: html, headers: { ...headers, 'content-type': 'text/html; charset=utf-8' } });
         });
 
         const response = await tab.goto(job.origin + page.url, { waitUntil: 'load' });
diff --git a/tests/helpers/theme_bootstrap.cjs b/tests/helpers/theme_bootstrap.cjs
new file mode 100644
index 000000000..1632856fb
--- /dev/null
+++ b/tests/helpers/theme_bootstrap.cjs
@@ -0,0 +1,13 @@
+// Runs inside a browser via Playwright evaluate; parsing does not execute code.
+function extractThemeBootstrap(html) {
+  const doc = new DOMParser().parseFromString(html, 'text/html');
+  const matches = Array.from(doc.querySelectorAll('script:not([src])'))
+    .map(script => script.textContent)
+    .filter(code => code.includes('Apply font early'));
+  if (matches.length !== 1) {
+    throw new Error(`Expected one early theme bootstrap, found ${matches.length}`);
+  }
+  return matches[0];
+}
+
+module.exports = { extractThemeBootstrap };
diff --git a/tests/publication_plan_b_browser.cjs b/tests/publication_plan_b_browser.cjs
index 929201bf7..f3debc34f 100644
--- a/tests/publication_plan_b_browser.cjs
+++ b/tests/publication_plan_b_browser.cjs
@@ -2,6 +2,7 @@
 const { chromium } = require('playwright');
 const { readFileSync } = require('fs');
 const assert = require('node:assert/strict');
+const { extractThemeBootstrap } = require('./helpers/theme_bootstrap.cjs');
 
 (async () => {
   const origin = process.env.ODYSSEUS_TEST_STATIC_ORIGIN;
@@ -111,7 +112,7 @@ const assert = require('node:assert/strict');
 
     // Verify the real early bootstrap handles persisted legacy preferences.
     const appHtml = readFileSync('static/index.html', 'utf8');
-    const bootstrap = [...appHtml.matchAll(/<script(?:\s[^>]*)?>([\s\S]*?)<\/script>/g)].map(m => m[1]).find(code => code.includes('Apply font early'));
+    const bootstrap = await page.evaluate(extractThemeBootstrap, appHtml);
     assert(bootstrap);
     const early = await page.evaluate(async code => {
       const theme = await import('/static/js/theme.js');
diff --git a/tests/test_chatgpt_subscription_routes.py b/tests/test_chatgpt_subscription_routes.py
index 3f35da339..5714bc4b3 100644
--- a/tests/test_chatgpt_subscription_routes.py
+++ b/tests/test_chatgpt_subscription_routes.py
@@ -2,6 +2,7 @@
 
 import json
 from types import SimpleNamespace
+from uuid import UUID
 
 import pytest
 from sqlalchemy import create_engine
@@ -22,6 +23,32 @@ def _mem_db(monkeypatch):
     return TestSessionLocal
 
 
+def test_provider_auth_identifier_is_generated_independently_of_credentials(monkeypatch):
+    TestSessionLocal = _mem_db(monkeypatch)
+    identifiers = iter([
+        UUID("12345678-0000-4000-8000-000000000001"),
+        UUID("87654321-0000-4000-8000-000000000002"),
+    ])
+    monkeypatch.setattr(csr.uuid, "uuid4", lambda: next(identifiers))
+    monkeypatch.setattr(csr.chatgpt_subscription, "fetch_available_models", lambda token: ["fixture-model"])
+    tokens = {"access_token": "ACCESS-SENTINEL", "refresh_token": "REFRESH-SENTINEL",
+              "api_key": "KEY-SENTINEL", "password": "PASSWORD-SENTINEL", "account_id": "ACCOUNT-SENTINEL"}
+    result = csr._provision_endpoint(tokens, "alice", label="label-sentinel")
+    assert result["provider_auth_id"] == "12345678"
+    assert result["id"] == "87654321"
+    assert not any(value in json.dumps(result) for value in tokens.values())
+    db = TestSessionLocal()
+    try:
+        auth = db.query(ProviderAuthSession).filter_by(id=result["provider_auth_id"]).one()
+        endpoint = db.query(ModelEndpoint).filter_by(id=result["id"]).one()
+        assert auth.access_token == tokens["access_token"]
+        assert auth.refresh_token == tokens["refresh_token"]
+        assert endpoint.provider_auth_id == auth.id
+        assert endpoint.api_key is None
+    finally:
+        db.close()
+
+
 def test_provision_creates_owner_scoped_auth_session_and_endpoint(monkeypatch):
     TestSessionLocal = _mem_db(monkeypatch)
     monkeypatch.setattr(csr.chatgpt_subscription, "fetch_available_models", lambda token: ["gpt-5.5", "o4-mini"])
diff --git a/tests/test_codeql_security_js.py b/tests/test_codeql_security_js.py
new file mode 100644
index 000000000..d3552fb07
--- /dev/null
+++ b/tests/test_codeql_security_js.py
@@ -0,0 +1,17 @@
+"""Real Chromium regressions for the corrected CodeQL data-flow contracts."""
+import json
+import subprocess
+from pathlib import Path
+
+
+def test_codeql_security_browser_contracts():
+    root = Path(__file__).resolve().parents[1]
+    result = subprocess.run(
+        ["node", "tests/codeql_security_browser.cjs"], cwd=root,
+        capture_output=True, text=True, timeout=60,
+    )
+    assert result.returncode == 0, result.stdout + result.stderr
+    assert json.loads(result.stdout) == {
+        "chat": True, "markdown": True, "svg": True,
+        "menus": True, "admin": True, "bootstrap": True,
+    }
diff --git a/tests/test_css_computed_style_snapshot.py b/tests/test_css_computed_style_snapshot.py
index 79aaa28a8..173f8a257 100644
--- a/tests/test_css_computed_style_snapshot.py
+++ b/tests/test_css_computed_style_snapshot.py
@@ -67,6 +67,37 @@ def test_baseline_covers_every_inventory_entry():
         assert set(baseline["variants"][name]) == variant_names
 
 
+@_requires_browser
+def test_capture_does_not_execute_script_markup_or_handlers(tmp_path):
+    """Use the real capture subprocess: every script vector would turn green."""
+    attack = "document.getElementById('guard').style.color='rgb(0, 128, 0)'"
+    source = f'''<!doctype html><html><head><style>#guard {{ color: rgb(255, 0, 0); }}</style></head>
+      <body onload="{attack}"><div id="guard">Stable</div>
+      <script>{attack}</script >
+      <SCRIPT>{attack}</SCRIPT>
+      <script data-note=">">{attack}</script\t>
+      <script src="attack.js"></script>
+      <svg onload="{attack}"><script>{attack}</script></svg>
+      <img src=x onerror="{attack}">
+      <template><script>{attack}</script></template>
+      </body></html>'''
+    (tmp_path / "fixture.html").write_text(source)
+    (tmp_path / "attack.js").write_text(attack)
+    inventory = {
+        "properties": ["color"],
+        "variants": [snapshot.load_inventory()["variants"][0]],
+        "pages": [{"name": "fixture", "url": "/fixture.html",
+                   "elements": [{"key": "guard", "selector": "#guard"}]}],
+    }
+    origin, shutdown = snapshot.serve_repository(tmp_path)
+    try:
+        captured = snapshot.capture(origin, inventory, measurement_delay_ms=100)
+        assert captured["missing"] == {}
+        assert captured["snapshot"]["fixture"][inventory["variants"][0]["name"]]["guard"]["color"] == "rgb(255, 0, 0)"
+    finally:
+        shutdown()
+
+
 @_requires_browser
 def test_computed_styles_match_the_committed_baseline():
     captured = snapshot.capture(static_origin())
diff --git a/tests/test_markdown_rendering_js.py b/tests/test_markdown_rendering_js.py
index 06dea0485..34cc18265 100644
--- a/tests/test_markdown_rendering_js.py
+++ b/tests/test_markdown_rendering_js.py
@@ -1,6 +1,7 @@
 """Regression coverage for the browser markdown renderer."""
 
 import json
+import os
 import shutil
 import subprocess
 import textwrap
@@ -112,6 +113,32 @@ def _run_markdown_case(markdown: str, render_expr: str = "mod.mdToHtml(input)",
     return json.loads(result.stdout.splitlines()[-1])["html"]
 
 
+def _run_svg_case(markdown: str):
+    # SVG title extraction requires a real inert DOM, not the Node template stub.
+    script = r'''
+      const { chromium } = require('playwright');
+      (async () => {
+        const browser = await chromium.launch({ headless: true });
+        try {
+          const page = await browser.newPage();
+          await page.goto(process.env.ODYSSEUS_TEST_STATIC_ORIGIN + '/static/js/documentStats.js');
+          await page.setContent('<div id="toast"></div><div id="sidebar"></div>');
+          const html = await page.evaluate(async input => {
+            const mod = await import('/static/js/markdown.js');
+            return mod.mdToHtml(input);
+          }, JSON.parse(process.env.ODYSSEUS_SVG_TEST_INPUT));
+          console.log(JSON.stringify({ html }));
+        } finally { await browser.close(); }
+      })().catch(error => { console.error(error); process.exit(1); });
+    '''
+    result = subprocess.run(
+        ["node", "-e", script], cwd=_REPO, capture_output=True, text=True,
+        env={**os.environ, "ODYSSEUS_SVG_TEST_INPUT": json.dumps(markdown)}, timeout=30,
+    )
+    assert result.returncode == 0, result.stderr
+    return json.loads(result.stdout)["html"]
+
+
 def test_ordered_lists_render_as_one_unwrapped_ol(node_available):
     html = _run_markdown_case(
         "Before\n\n"
@@ -134,7 +161,7 @@ def test_ordered_lists_render_as_one_unwrapped_ol(node_available):
 
 
 def test_fenced_svg_renders_inline_in_a_locked_sandbox(node_available):
-    html = _run_markdown_case(
+    html = _run_svg_case(
         "```svg\n"
         '<svg viewBox="0 0 1200 800"><title>Black hole formation</title>'
         '<circle cx="200" cy="300" r="80"/></svg>\n'
@@ -158,7 +185,7 @@ def test_fenced_svg_renders_inline_in_a_locked_sandbox(node_available):
 
 
 def test_multiple_fenced_svgs_remain_interleaved_with_explanations(node_available):
-    html = _run_markdown_case(
+    html = _run_svg_case(
         "```svg\n"
         '<svg viewBox="0 0 720 360"><title>Stage one</title></svg>\n'
         "```\n\nThe first mechanism explained.\n\n"
@@ -174,7 +201,7 @@ def test_multiple_fenced_svgs_remain_interleaved_with_explanations(node_availabl
 
 
 def test_complete_raw_svg_uses_the_same_locked_renderer(node_available):
-    html = _run_markdown_case(
+    html = _run_svg_case(
         "Before the visual.\n\n"
         '<svg viewBox="0 0 720 360"><title>Raw model SVG</title>'
         '<rect width="720" height="360" fill="var(--bg)"/></svg>'