diff --git a/documentation/how-to.md b/documentation/how-to.md
index fa04f4649..2a12ac966 100644
--- a/documentation/how-to.md
+++ b/documentation/how-to.md
@@ -321,6 +321,22 @@ as before, and an embed that passes a token keeps getting Mapbox under `auto`.
 
 ---
 
+## Embed under a strict Content-Security-Policy
+
+No bundle needs `'unsafe-eval'` (translations compile without `eval`; `bun run check:no-eval`), and
+every third-party script is pinned with an integrity hash (`library/constants/cdn.js`,
+`bun run check:cdn-pins`). A page embedding the maps needs, in addition to its own sources:
+
+| Directive | Add | Why |
+|---|---|---|
+| `script-src` | `https://cdn.jsdelivr.net` (and `https://api.mapbox.com` for Mapbox) | the map engine and the search geocoder |
+| `style-src` | `'unsafe-inline'`, the same CDN hosts | each plugin styles its own shadow root with a `<style>` element |
+| `worker-src` | `blob:` | the map engines run their tile workers from a blob URL |
+| `connect-src` | the tile/style hosts you use (`https://tiles.openfreemap.org` for MapLibre, `https://*.mapbox.com` for Mapbox), your data API | tiles, styles, glyphs, data |
+| `img-src` | `data:` `blob:` and the same tile hosts | sprites and raster tiles |
+
+---
+
 ## Set the API + Mapbox token
 
 Both the data backend and the Mapbox token are **runtime inputs**, never baked into a bundle.
diff --git a/internal/check-no-eval.mjs b/internal/check-no-eval.mjs
new file mode 100644
index 000000000..f3fd80a4f
--- /dev/null
+++ b/internal/check-no-eval.mjs
@@ -0,0 +1,69 @@
+#!/usr/bin/env node
+/**
+ * check-no-eval — no bundle needs CSP 'unsafe-eval', and translations still render without it. Headless.
+ *
+ * CRITIC-4 (2026-09-26): vue-i18n's default message compiler builds every message with `new Function`,
+ * so 20 of 25 bundles needed 'unsafe-eval' and a partner with a strict Content-Security-Policy got no
+ * translated text. vite.config.js now defines __INTLIFY_JIT_COMPILATION__ (compile to an AST, no eval).
+ *
+ * ASSERTS  (1) BUILT: no bundle under public/<tree>/ contains `new Function(` or a bare `eval(`.
+ *          (2) RUNTIME: vue-i18n in JIT mode, with the global Function constructor and eval DISABLED
+ *              (they throw, as under a strict CSP), renders real catalogue messages — plain,
+ *              {named} interpolation and plural — in en and ar, from library/i18n/locales.
+ * EXIT 0 pass · 1 fail
+ */
+import { readFileSync, readdirSync, existsSync } from 'node:fs'
+import { join, resolve, dirname } from 'node:path'
+import { fileURLToPath } from 'node:url'
+import { TREE_NAME } from './_tree-name.mjs'
+
+const ROOT = resolve(dirname(fileURLToPath(import.meta.url)), '..')
+let bad = 0
+// ── (1) built output ──
+const TREE = join(ROOT, 'public', TREE_NAME)
+let bundles = 0
+for (const d of existsSync(TREE) ? readdirSync(TREE) : []) {
+  const f = join(TREE, d, `${d}.js`)
+  if (!existsSync(f)) continue
+  bundles++
+  const src = readFileSync(f, 'utf8')
+  const nf = (src.match(/new Function\s*\(/g) || []).length, ev = (src.match(/(^|[^\w$.])eval\s*\(/g) || []).length
+  if (nf || ev) { bad++; console.log(`  FAIL  ${d}.js: ${nf} new Function, ${ev} eval — needs CSP 'unsafe-eval'`) }
+}
+if (!bundles) { bad++; console.log('  FAIL  no built bundles found (vacuous)') }
+else console.log(`  ${bad ? '    ' : 'ok  '}  ${bundles} built bundle(s) scanned for new Function / eval`)
+
+// ── (2) runtime, with eval unavailable ──
+globalThis.__INTLIFY_JIT_COMPILATION__ = true
+globalThis.__INTLIFY_DROP_MESSAGE_COMPILER__ = false
+globalThis.__VUE_I18N_FULL_INSTALL__ = true
+globalThis.__VUE_I18N_LEGACY_API__ = false
+globalThis.__INTLIFY_PROD_DEVTOOLS__ = false
+const { createI18n } = await import('vue-i18n')
+const RealFunction = globalThis.Function
+globalThis.eval = () => { throw new EvalError('CSP: eval blocked') }
+globalThis.Function = new Proxy(RealFunction, { construct() { throw new EvalError('CSP: new Function blocked') }, apply() { throw new EvalError('CSP: Function blocked') } })
+const cat = (lc, area) => JSON.parse(readFileSync(join(ROOT, 'library/i18n/locales', lc, `${area}.json`), 'utf8'))
+const walk = (o, p = '') => Object.entries(o).flatMap(([k, v]) => (v && typeof v === 'object' ? walk(v, p + k + '.') : [[p + k, v]]))
+for (const lc of ['en', 'ar']) {
+  const messages = { [lc]: { studio: cat(lc, 'studio'), search: cat(lc, 'search') } }
+  const i18n = createI18n({ legacy: false, locale: lc, messages, missingWarn: false, fallbackWarn: false })
+  const t = i18n.global.t
+  const keys = walk(messages[lc]).filter(([, v]) => typeof v === 'string')
+  const named = keys.find(([, v]) => /\{\w+\}/.test(v))
+  let n = 0
+  try {
+    for (const [k, v] of keys) {
+      const vars = {}; for (const m of v.matchAll(/\{(\w+)\}/g)) vars[m[1]] = 'X'
+      const out = t(k, vars)
+      if (typeof out !== 'string' || !out) throw new Error(`${k}: rendered nothing`)
+      if (/\{\w+\}/.test(out)) throw new Error(`${k}: placeholder left in "${out}"`)
+      n++
+    }
+    const nv = named ? t(named[0], Object.fromEntries([...named[1].matchAll(/\{(\w+)\}/g)].map((m) => [m[1], 'Q']))) : ''
+    console.log(`  ok    ${lc}: ${n} studio/search messages rendered with eval blocked${named ? ` (e.g. ${named[0]} → "${nv.slice(0, 50)}")` : ''}`)
+  } catch (e) { bad++; console.log(`  FAIL  ${lc}: ${e.message}`) }
+}
+globalThis.Function = RealFunction
+if (bad) { console.log(`NO-EVAL: FAIL — ${bad} problem(s).`); process.exit(1) }
+console.log("NO-EVAL: PASS — no bundle needs 'unsafe-eval', and translations render with eval blocked.")
diff --git a/vite.config.js b/vite.config.js
index 91b6ae727..0220c1a4f 100644
--- a/vite.config.js
+++ b/vite.config.js
@@ -99,6 +99,12 @@ export default defineConfig(({ command, mode }) => {
     // port. `--host` on the command line still overrides this for a deliberate LAN session.
     server: { host: '127.0.0.1' },
     define: {
+      // ★ NO 'unsafe-eval' (CRITIC-4, 2026-09-26). vue-i18n's default message compiler builds each message
+      // with `new Function`, so a partner with a strict Content-Security-Policy saw every translated string
+      // fail. The JIT compiler (vue-i18n >= 9.3) compiles messages to an AST and evaluates it without eval;
+      // defining the flag lets the bundler drop the eval path entirely (check:no-eval asserts it).
+      __INTLIFY_JIT_COMPILATION__: 'true',
+      __INTLIFY_DROP_MESSAGE_COMPILER__: 'false',
       __DOXA_QA__: JSON.stringify(process.env.DOXA_QA === '1'),
       // The output tree's name (vite.doxa-maps-build-config.json `name`, the same value OUT_ROOT uses),
       // for the few runtime paths that must name the tree — so renaming the tree needs no source edit.