diff --git a/internal/_serve-reaped.mjs b/internal/_serve-reaped.mjs
index 95395de20..0eb5a4ae0 100644
--- a/internal/_serve-reaped.mjs
+++ b/internal/_serve-reaped.mjs
@@ -34,7 +34,7 @@ const HERE = dirname(fileURLToPath(import.meta.url))
 export function serveReaped(directory, port) {
   const child = spawn(
     process.execPath,
-    [resolve(HERE, 'serve-strict.mjs'), '--port', String(port), '--directory', directory],
+    [resolve(HERE, 'serve-strict.mjs'), '--port', String(port), '--directory', directory, '--exit-with-parent'],
     { stdio: 'ignore' },
   )
 
diff --git a/internal/check-auto-engine.mjs b/internal/check-auto-engine.mjs
index cdfbbf21c..c97dc2694 100644
--- a/internal/check-auto-engine.mjs
+++ b/internal/check-auto-engine.mjs
@@ -50,7 +50,7 @@ const FAKE_TOKEN = ['pk', b64({ u: 'auto-engine-check', a: 'not-a-real-token' })
 if (!existsSync(join(DIR, TREE_NAME, LEAF, 'index.html'))) { console.log(`AUTO-ENGINE: NOT MEASURED — no ${LEAF} under ${DIR}/${TREE_NAME}/`); process.exit(75) }
 
 const port = await new Promise((ok) => { const s = createServer().listen(0, '127.0.0.1', () => { const n = s.address().port; s.close(() => ok(n)) }) })
-const srv = spawn(process.execPath, [resolve(ROOT, 'internal/serve-strict.mjs'), '--port', String(port), '--directory', DIR], { stdio: 'ignore' })
+const srv = spawn(process.execPath, [resolve(ROOT, 'internal/serve-strict.mjs'), '--port', String(port), '--directory', DIR, '--exit-with-parent'], { stdio: 'ignore' })
 const stop = () => { try { srv.kill() } catch { /* gone */ } }
 let up = false
 for (let i = 0; i < 40 && !up; i++) { await new Promise((r) => setTimeout(r, 150)); up = await fetch(`http://127.0.0.1:${port}/${TREE_NAME}/manifest.json`).then((r) => r.ok).catch(() => false) }
diff --git a/internal/check-basemap-labels-localized.mjs b/internal/check-basemap-labels-localized.mjs
index 442981d17..841765ec7 100644
--- a/internal/check-basemap-labels-localized.mjs
+++ b/internal/check-basemap-labels-localized.mjs
@@ -40,7 +40,7 @@ const LEAF = arg('--leaf', 'doxa-simple-map/doxa-simple-map')
 const PAIRS = { Germany: 'Германия', Ukraine: 'Украина', Turkey: 'Турция', Egypt: 'Египет', Kazakhstan: 'Казахстан', Poland: 'Польша' }
 
 const port = await new Promise((ok) => { const s = createServer().listen(0, '127.0.0.1', () => { const p = s.address().port; s.close(() => ok(p)) }) })
-const srv = spawn(process.execPath, [resolve(ROOT, 'internal/serve-strict.mjs'), '--port', String(port), '--directory', DIR], { stdio: 'ignore' })
+const srv = spawn(process.execPath, [resolve(ROOT, 'internal/serve-strict.mjs'), '--port', String(port), '--directory', DIR, '--exit-with-parent'], { stdio: 'ignore' })
 await new Promise((r) => setTimeout(r, 900))
 const up = await fetch(`http://127.0.0.1:${port}/${TREE_NAME}/${LEAF}/index.html`).then((r) => r.ok).catch(() => false)
 if (!up) { srv.kill(); console.log(`BASEMAP-LABELS: NOT MEASURED — could not serve ${DIR}`); process.exit(2) }
diff --git a/internal/check-composite-embed-knobs.mjs b/internal/check-composite-embed-knobs.mjs
index d4e347e75..150ef38bd 100644
--- a/internal/check-composite-embed-knobs.mjs
+++ b/internal/check-composite-embed-knobs.mjs
@@ -134,7 +134,7 @@ const HOST_PORT = await freePort()
 const TREE = `http://127.0.0.1:${TREE_PORT}/${TREE_NAME}`
 
 let pageHtml = '<!doctype html><html><body>nothing yet</body></html>'
-const tree = spawn(process.execPath, ['internal/serve-strict.mjs', '--port', String(TREE_PORT)], { cwd: ROOT, stdio: 'ignore' })
+const tree = spawn(process.execPath, ['internal/serve-strict.mjs', '--port', String(TREE_PORT), '--exit-with-parent'], { cwd: ROOT, stdio: 'ignore' })
 const host = createServer((_, r) => { r.writeHead(200, { 'content-type': 'text/html' }); r.end(pageHtml) }).listen(HOST_PORT, 'localhost')
 const cleanup = () => { try { tree.kill() } catch { /* already gone */ } try { host.close() } catch { /* already closed */ } }
 await new Promise((r) => setTimeout(r, 900))
diff --git a/internal/check-element-census-vs-live.mjs b/internal/check-element-census-vs-live.mjs
index 5799da819..fa5ec9efb 100644
--- a/internal/check-element-census-vs-live.mjs
+++ b/internal/check-element-census-vs-live.mjs
@@ -99,7 +99,7 @@ for (const [, p] of presets) for (const pg of p.pages) {
 
 // ── our side: this checkout's tree on an OS-assigned port ─────────────────────────────────────────
 const port = await new Promise((ok) => { const s = createServer().listen(0, '127.0.0.1', () => { const n = s.address().port; s.close(() => ok(n)) }) })
-const srv = spawn(process.execPath, [resolve(ROOT, 'internal/serve-strict.mjs'), '--port', String(port), '--directory', DIR], { stdio: 'ignore' })
+const srv = spawn(process.execPath, [resolve(ROOT, 'internal/serve-strict.mjs'), '--port', String(port), '--directory', DIR, '--exit-with-parent'], { stdio: 'ignore' })
 const stopSrv = () => { try { srv.kill() } catch { /* already gone */ } }
 let up = false
 for (let i = 0; i < 40 && !up; i++) { await new Promise((r) => setTimeout(r, 150)); up = await fetch(`http://127.0.0.1:${port}/${TREE_NAME}/manifest.json`).then((r) => r.ok).catch(() => false) }
diff --git a/internal/check-experimental-shelf.mjs b/internal/check-experimental-shelf.mjs
index 332572495..bae86a062 100644
--- a/internal/check-experimental-shelf.mjs
+++ b/internal/check-experimental-shelf.mjs
@@ -105,7 +105,7 @@ const SEED = {
 
 // ── our own server, on a port nobody else can be holding ──────────────────────
 const port = await new Promise(ok => { const s = createServer().listen(0, '127.0.0.1', () => { const p = s.address().port; s.close(() => ok(p)) }) })
-const srv = spawn(process.execPath, [resolve(ROOT, 'internal/serve-strict.mjs'), '--port', String(port), '--directory', 'public'], { cwd: ROOT, stdio: 'ignore' })
+const srv = spawn(process.execPath, [resolve(ROOT, 'internal/serve-strict.mjs'), '--port', String(port), '--directory', 'public', '--exit-with-parent'], { cwd: ROOT, stdio: 'ignore' })
 const reap = () => { try { srv.kill() } catch (_) {} }
 process.on('exit', reap); for (const s of ['SIGINT', 'SIGTERM']) process.on(s, () => { reap(); process.exit(130) })
 const BASE = `http://127.0.0.1:${port}/${TREE_NAME}`
diff --git a/internal/check-fits-the-screen.mjs b/internal/check-fits-the-screen.mjs
index 49017a7cf..5e441413e 100644
--- a/internal/check-fits-the-screen.mjs
+++ b/internal/check-fits-the-screen.mjs
@@ -124,7 +124,7 @@ for (const b of mf.bundles || []) {
 }
 
 // ── 2. SERVE THE BUILT TREE the way production serves it (directories 404) ─────────────────────
-const server = spawn(process.execPath, ['internal/serve-strict.mjs', '--port', String(PORT), '--directory', 'public'], {
+const server = spawn(process.execPath, ['internal/serve-strict.mjs', '--port', String(PORT), '--directory', 'public', '--exit-with-parent'], {
   cwd: ROOT, stdio: 'pipe',
 })
 let serverErr = ''
diff --git a/internal/check-host-locale-contract.mjs b/internal/check-host-locale-contract.mjs
index 2684c1c91..6bd8bc6ca 100644
--- a/internal/check-host-locale-contract.mjs
+++ b/internal/check-host-locale-contract.mjs
@@ -63,7 +63,7 @@ for (const b of manifest.bundles || []) for (const p of b.profiles || []) {
 if (!leaves.includes(CONTROL)) { console.log(`HOST-LOCALE: NOT MEASURED — the control ${CONTROL} is not in this tree`); process.exit(75) }
 
 const port = await new Promise((ok) => { const s = createServer().listen(0, '127.0.0.1', () => { const p = s.address().port; s.close(() => ok(p)) }) })
-const srv = spawn(process.execPath, [resolve(ROOT, 'internal/serve-strict.mjs'), '--port', String(port), '--directory', DIR], { stdio: 'ignore' })
+const srv = spawn(process.execPath, [resolve(ROOT, 'internal/serve-strict.mjs'), '--port', String(port), '--directory', DIR, '--exit-with-parent'], { stdio: 'ignore' })
 const stop = () => { try { srv.kill() } catch { /* already gone */ } }
 let up = false
 for (let i = 0; i < 40 && !up; i++) { await new Promise((r) => setTimeout(r, 150)); up = await fetch(`http://127.0.0.1:${port}/${TREE_NAME}/manifest.json`).then((r) => r.ok).catch(() => false) }
diff --git a/internal/check-leaf-engine-per-provider.mjs b/internal/check-leaf-engine-per-provider.mjs
index ef0efa4ec..3fb82dbb9 100644
--- a/internal/check-leaf-engine-per-provider.mjs
+++ b/internal/check-leaf-engine-per-provider.mjs
@@ -62,7 +62,7 @@ if (!leaves.length) { console.log('LEAF-ENGINE: NOT MEASURED — no leaves match
 
 async function serve(dir) {
   const port = await new Promise((ok) => { const s = createServer().listen(0, '127.0.0.1', () => { const n = s.address().port; s.close(() => ok(n)) }) })
-  const srv = spawn(process.execPath, [resolve(ROOT, 'internal/serve-strict.mjs'), '--port', String(port), '--directory', dir], { stdio: 'ignore' })
+  const srv = spawn(process.execPath, [resolve(ROOT, 'internal/serve-strict.mjs'), '--port', String(port), '--directory', dir, '--exit-with-parent'], { stdio: 'ignore' })
   let up = false
   for (let i = 0; i < 40 && !up; i++) { await new Promise((r) => setTimeout(r, 150)); up = await fetch(`http://127.0.0.1:${port}/${TREE_NAME}/manifest.json`).then((r) => r.ok).catch(() => false) }
   if (!up) { try { srv.kill() } catch { /* gone */ } return null }
diff --git a/internal/check-map-embed-cells.mjs b/internal/check-map-embed-cells.mjs
index d323adf13..9a7622b42 100644
--- a/internal/check-map-embed-cells.mjs
+++ b/internal/check-map-embed-cells.mjs
@@ -70,7 +70,7 @@ const TREE_PORT = await freePort()
 const HOST_PORT = await freePort()
 const TREE = `http://127.0.0.1:${TREE_PORT}/${TREE_NAME}`
 let pageHtml = '<!doctype html><title>host</title><body>nothing</body>'
-const tree = spawn(process.execPath, ['internal/serve-strict.mjs', '--port', String(TREE_PORT)], { cwd: ROOT, stdio: 'ignore' })
+const tree = spawn(process.execPath, ['internal/serve-strict.mjs', '--port', String(TREE_PORT), '--exit-with-parent'], { cwd: ROOT, stdio: 'ignore' })
 const host = createServer((_, r) => { r.writeHead(200, { 'content-type': 'text/html; charset=utf-8' }); r.end(pageHtml) }).listen(HOST_PORT, 'localhost')
 const cleanup = () => { try { tree.kill() } catch (_) {} try { host.close() } catch (_) {} }
 await new Promise((r) => setTimeout(r, 900))
diff --git a/internal/check-mapbox-drew.mjs b/internal/check-mapbox-drew.mjs
index 55993778d..22ea77ed8 100644
--- a/internal/check-mapbox-drew.mjs
+++ b/internal/check-mapbox-drew.mjs
@@ -93,7 +93,7 @@ if (!leaves.length) { console.log('MAPBOX-DREW: NOT MEASURED — no composed map
 
 async function serve(dir) {
   const port = await new Promise((ok) => { const s = createServer().listen(0, '127.0.0.1', () => { const n = s.address().port; s.close(() => ok(n)) }) })
-  const srv = spawn(process.execPath, [resolve(ROOT, 'internal/serve-strict.mjs'), '--port', String(port), '--directory', dir], { stdio: 'ignore' })
+  const srv = spawn(process.execPath, [resolve(ROOT, 'internal/serve-strict.mjs'), '--port', String(port), '--directory', dir, '--exit-with-parent'], { stdio: 'ignore' })
   await new Promise((r) => setTimeout(r, 600))
   return { port, stop: () => { try { srv.kill() } catch (_) {} } }
 }
diff --git a/internal/check-prayer-walk-planner.mjs b/internal/check-prayer-walk-planner.mjs
index 8bd13ac1b..bd46e7591 100644
--- a/internal/check-prayer-walk-planner.mjs
+++ b/internal/check-prayer-walk-planner.mjs
@@ -34,7 +34,7 @@ try { ({ chromium } = await import('./lib/playwright-guarded.mjs')) } catch { co
 const OUT = process.env.OUT || '/tmp'
 const free = () => new Promise(ok => { const s = createServer().listen(0, '127.0.0.1', () => { const p = s.address().port; s.close(() => ok(p)) }) })
 const TP = await free(), HP = await free(), TREE = `http://127.0.0.1:${TP}/${TREE_NAME}`
-const srv = spawn('node', ['internal/serve-strict.mjs', '--port', String(TP)], { cwd: ROOT, stdio: 'ignore' })
+const srv = spawn('node', ['internal/serve-strict.mjs', '--port', String(TP), '--exit-with-parent'], { cwd: ROOT, stdio: 'ignore' })
 const host = createServer((q, r) => { const l = new URL(q.url, 'http://x').searchParams.get('l') || 'en'; r.writeHead(200, { 'content-type': 'text/html' }); r.end(`<!doctype html><html lang="${l}"><body style="margin:0"><script src="${TREE}/doxa-maps-spa/doxa-maps-spa.js"></script><doxa-maps-spa tab="prayer-walk-planner" style="height:100vh"></doxa-maps-spa></body></html>`) }).listen(HP, 'localhost')
 await new Promise(r => setTimeout(r, 800))
 
diff --git a/internal/check-research-gallery-embed.mjs b/internal/check-research-gallery-embed.mjs
index 90b2d7a29..8813fe524 100644
--- a/internal/check-research-gallery-embed.mjs
+++ b/internal/check-research-gallery-embed.mjs
@@ -139,7 +139,7 @@ const hostPage = () => {
 <style>body{margin:0} header,footer{height:60px;background:#eee}</style></head>
 <body><header id=hdr>HOST HEADER</header><main style="max-width:1200px;margin:0 auto">${embed}</main><footer>HOST FOOTER</footer></body></html>`
 }
-const tree = spawn(process.execPath, ['internal/serve-strict.mjs', '--port', String(TREE_PORT)], { cwd: ROOT, stdio: 'ignore', env: { ...process.env, LIVE_CORS: LIVE_CORS ? '1' : '' } })
+const tree = spawn(process.execPath, ['internal/serve-strict.mjs', '--port', String(TREE_PORT), '--exit-with-parent'], { cwd: ROOT, stdio: 'ignore', env: { ...process.env, LIVE_CORS: LIVE_CORS ? '1' : '' } })
 const host = createServer((_, r) => { r.writeHead(200, { 'content-type': 'text/html' }); r.end(hostPage()) }).listen(HOST_PORT, 'localhost')
 const cleanup = () => { try { tree.kill() } catch {} try { host.close() } catch {} }
 await new Promise(r => setTimeout(r, 800))
diff --git a/internal/measure-map-load.mjs b/internal/measure-map-load.mjs
index 853730f9f..0de36ccd7 100644
--- a/internal/measure-map-load.mjs
+++ b/internal/measure-map-load.mjs
@@ -29,7 +29,7 @@ const ONLY = arg('--only', '') ? arg('--only', '').split(',') : DEFAULT
 const manifest = JSON.parse(readFileSync(`public/${TREE_NAME}/manifest.json`, 'utf8'))
 
 const port = await new Promise((ok) => { const s = createServer().listen(0, '127.0.0.1', () => { const p = s.address().port; s.close(() => ok(p)) }) })
-const srv = spawn(process.execPath, ['internal/serve-strict.mjs', '--port', String(port)], { stdio: 'ignore' })
+const srv = spawn(process.execPath, ['internal/serve-strict.mjs', '--port', String(port), '--exit-with-parent'], { stdio: 'ignore' })
 const hostPort = await new Promise((ok) => { const s = createServer().listen(0, '127.0.0.1', () => { const p = s.address().port; s.close(() => ok(p)) }) })
 let hostHtml = ''
 const host = createServer((_, r) => { r.writeHead(200, { 'content-type': 'text/html; charset=utf-8' }); r.end(hostHtml) }).listen(hostPort, 'localhost')
diff --git a/internal/serve-strict.mjs b/internal/serve-strict.mjs
index 8d6b3c60a..197467733 100644
--- a/internal/serve-strict.mjs
+++ b/internal/serve-strict.mjs
@@ -33,7 +33,11 @@
  * HTTP 200 on the box's PUBLIC IP while a browser gate was running. Override with HOST only if you
  * deliberately want another host to reach it.
  *
- * Usage: node internal/serve-strict.mjs [--port 4173] [--directory public]
+ * Usage: node internal/serve-strict.mjs [--port 4173] [--directory public] [--exit-with-parent]
+ *   --exit-with-parent  for a gate that spawns this server: exit once the process that started it is gone.
+ *                       A gate that crashes or is refused by the browser-slot guard cannot kill its child, and
+ *                       on 2026-09-29 41 such servers had outlived their gates (279 MB, the oldest 5 days).
+ *                       Opt-in, so a server someone deliberately left running is never taken down.
  */
 import { createServer } from 'node:http'
 import { createReadStream, statSync } from 'node:fs'
@@ -49,6 +53,10 @@ const argOf = (name, dflt) => { const i = argv.indexOf(name); return i >= 0 && a
 const PORT = Number(process.env.PORT || argOf('--port', '4173'))
 const HOST = process.env.HOST || '127.0.0.1'
 const DIR = resolve(ROOT, argOf('--directory', 'public'))
+if (argv.includes('--exit-with-parent')) {
+  const parent = process.ppid
+  setInterval(() => { if (process.ppid !== parent) process.exit(0) }, 2000).unref()
+}
 
 const TYPES = {
   '.html': 'text/html; charset=utf-8', '.js': 'text/javascript; charset=utf-8',
diff --git a/internal/verify-gospel-map.mjs b/internal/verify-gospel-map.mjs
index 8378c3559..7727619a6 100644
--- a/internal/verify-gospel-map.mjs
+++ b/internal/verify-gospel-map.mjs
@@ -117,7 +117,7 @@ if (adopted !== true) {
   // Ephemeral port so two gates running at once cannot collide on 4173.
   const port = 5100 + Math.floor(Math.random() * 800)
   base = `http://127.0.0.1:${port}`
-  server = spawn(process.execPath, [resolve(HERE, 'serve-strict.mjs'), '--port', String(port), '--directory', resolve(REPO, 'public')], { stdio: 'ignore', detached: false })
+  server = spawn(process.execPath, [resolve(HERE, 'serve-strict.mjs'), '--port', String(port), '--directory', resolve(REPO, 'public'), '--exit-with-parent'], { stdio: 'ignore', detached: false })
   const until = Date.now() + 15000
   while (Date.now() < until && !(await alive(base))) await new Promise((r) => setTimeout(r, 250))
   if (!(await alive(base))) {