diff --git a/internal/_serves-this-tree.mjs b/internal/_serves-this-tree.mjs
index eb1bd63ce..13c11e1cf 100644
--- a/internal/_serves-this-tree.mjs
+++ b/internal/_serves-this-tree.mjs
@@ -85,3 +85,41 @@ export async function serveThisTree(dir) {
   }
   return null
 }
+
+/**
+ * The same check, as a one-liner a gate can put right after it resolves its base URL.
+ *
+ * ★ EXIT 75, NOT 1. A gate pointed at another worktree's server has NOT MEASURED this build — it
+ * has not found a defect in it. flock uses 75 for the same idea (EX_TEMPFAIL) and the wave runner
+ * already reports 75 as ⊘ rather than ✗, so one code means "not measured" everywhere in this repo.
+ * Exiting 1 here would turn a mis-pointed probe into a red product gate, which is the failure this
+ * whole family of checks exists to prevent.
+ *
+ * @param {string} base   origin (or any URL on it) that should serve public/
+ * @param {string} repo   absolute path to the repo root
+ * @param {string} label  the gate's own name, for the message
+ */
+export async function requireThisTree(base, repo, label) {
+  let origin = String(base || '')
+  // A gate that loads file:// URLs is reading THIS checkout by construction — there is no server to
+  // be wrong about, so the guard stays silent rather than inventing a precondition.
+  if (!/^https?:/i.test(origin)) return { ok: true, why: 'not an http target' }
+  // ★ ONLY LOCAL SERVERS. The defect this guards is several worktrees sharing one machine's ports.
+  // A gate aimed at a DEPLOYED site (verify-map-paint defaults to the live host) is asking a
+  // different question on purpose — "does production match what we built" is a deploy check, not a
+  // mis-pointed probe — and enforcing local identity there would make it permanently unmeasured.
+  // MEASURED while rolling this out: that gate reported NOT MEASURED against the live site, which
+  // is the guard being wrong rather than the gate.
+  try {
+    const host = new URL(origin).hostname
+    if (!/^(localhost|127\.|0\.0\.0\.0$|\[?::1\]?$)/.test(host)) return { ok: true, why: 'remote target, not a worktree port' }
+  } catch { /* unparseable — fall through to the content check */ }
+  try { origin = new URL(origin).origin } catch { /* already an origin, or unusable — pass through */ }
+  const verdict = await servesThisTree(origin, repo)
+  if (/DIFFERENT build/.test(verdict.why)) {
+    console.log(`${label}: NOT MEASURED — ${verdict.why}`)
+    console.log('  Point this gate at a server for THIS checkout (bun run serve) and re-run.')
+    process.exit(75)
+  }
+  return verdict
+}
diff --git a/internal/check-aria-labels-localized.mjs b/internal/check-aria-labels-localized.mjs
index c15b9a076..c67bd36bf 100644
--- a/internal/check-aria-labels-localized.mjs
+++ b/internal/check-aria-labels-localized.mjs
@@ -27,8 +27,19 @@
 //
 // Usage: node internal/check-aria-labels-localized.mjs <leafUrl> [locales]
 import { chromium } from 'playwright'
+import { requireThisTree } from './_serves-this-tree.mjs'
+import { resolve as _resolvePath, dirname as _dirnamePath } from 'node:path'
+import { fileURLToPath as _fileURLToPath } from 'node:url'
 
 const URL_ = process.argv[2] || process.env.ARIA_URL
+const ROOT = _resolvePath(_dirnamePath(_fileURLToPath(import.meta.url)), '..')
+
+// ★ MEASURE THIS BUILD, OR MEASURE NOTHING. Several worktrees run on one machine and a default port
+// belongs to whichever server started first — measured 2026-09-24 on :4173, where browser gates
+// reported confidently about a build nobody here had touched. 75 (EX_TEMPFAIL), not 1: the wrong
+// tree is a precondition, not a product defect, and the wave runner reports 75 as ⊘ rather than ✗.
+// A file:// target passes straight through — there is no server there to be wrong about.
+await requireThisTree(URL_, ROOT, 'ARIA-LABELS-LOCALIZED')
 if (!URL_) {
   console.log('ARIA-LABELS-LOCALIZED: SKIP — no leaf url given.')
   console.log('  Pass one, or set ARIA_URL. Serve the TREE ROOT (public/) and point at a leaf,')
diff --git a/internal/check-card-deck.mjs b/internal/check-card-deck.mjs
index 2c2dec078..1beaf8587 100644
--- a/internal/check-card-deck.mjs
+++ b/internal/check-card-deck.mjs
@@ -13,8 +13,19 @@
 // Usage: node internal/check-card-deck.mjs [lang] [stock]
 //   PACKET_ORIGIN (default http://127.0.0.1:4898) · PACKET_API · PACKET_ISO3
 import { chromium } from 'playwright'
+import { requireThisTree } from './_serves-this-tree.mjs'
+import { resolve as _resolvePath, dirname as _dirnamePath } from 'node:path'
+import { fileURLToPath as _fileURLToPath } from 'node:url'
 
 const ORIGIN = process.env.PACKET_ORIGIN || 'http://127.0.0.1:4898'
+const ROOT = _resolvePath(_dirnamePath(_fileURLToPath(import.meta.url)), '..')
+
+// ★ MEASURE THIS BUILD, OR MEASURE NOTHING. Several worktrees run on one machine and a default port
+// belongs to whichever server started first — measured 2026-09-24 on :4173, where browser gates
+// reported confidently about a build nobody here had touched. 75 (EX_TEMPFAIL), not 1: the wrong
+// tree is a precondition, not a product defect, and the wave runner reports 75 as ⊘ rather than ✗.
+// A file:// target passes straight through — there is no server there to be wrong about.
+await requireThisTree(ORIGIN, ROOT, 'CARD-DECK')
 const API = process.env.PACKET_API || 'https://pray.doxa.life'
 const ISO3 = process.env.PACKET_ISO3 || 'LAO'
 const LANG = process.argv[2] || 'en'
diff --git a/internal/check-deck-click.mjs b/internal/check-deck-click.mjs
index 05c9dc235..153637296 100644
--- a/internal/check-deck-click.mjs
+++ b/internal/check-deck-click.mjs
@@ -17,8 +17,17 @@ import { chromium } from 'playwright'
 import { readFileSync, existsSync } from 'node:fs'
 import { resolve, dirname, join } from 'node:path'
 import { fileURLToPath } from 'node:url'
+import { requireThisTree } from './_serves-this-tree.mjs'
 
 const URL_ = process.argv[2]
+const ROOT = resolve(dirname(fileURLToPath(import.meta.url)), '..')
+
+// ★ MEASURE THIS BUILD, OR MEASURE NOTHING. Several worktrees run on one machine and a default port
+// belongs to whichever server started first — measured 2026-09-24 on :4173, where browser gates
+// reported confidently about a build nobody here had touched. 75 (EX_TEMPFAIL), not 1: the wrong
+// tree is a precondition, not a product defect, and the wave runner reports 75 as ⊘ rather than ✗.
+// A file:// target passes straight through — there is no server there to be wrong about.
+await requireThisTree(URL_, ROOT, 'DECK-CLICK')
 if (!URL_) { console.error('usage: check-deck-click.mjs <wallUrl> [stock] [expectedPage]'); process.exit(2) }
 const STOCK = process.argv[3] || ''
 const EXPECT_PAGE = process.argv[4] || (STOCK === 'pokerLandscape' ? '3.5in 2.5in' : '2.5in 3.5in')
diff --git a/internal/check-fixed-anchoring.mjs b/internal/check-fixed-anchoring.mjs
index dc3e6f4f8..c2f5efa4a 100644
--- a/internal/check-fixed-anchoring.mjs
+++ b/internal/check-fixed-anchoring.mjs
@@ -34,8 +34,19 @@
  * exactly where the old probe passed, which is the property that makes it worth having.
  */
 import { chromium } from 'playwright'
+import { requireThisTree } from './_serves-this-tree.mjs'
+import { resolve as _resolvePath, dirname as _dirnamePath } from 'node:path'
+import { fileURLToPath as _fileURLToPath } from 'node:url'
 
 const BASE = process.env.BASE || 'http://127.0.0.1:4173/doxa-maps'
+const ROOT = _resolvePath(_dirnamePath(_fileURLToPath(import.meta.url)), '..')
+
+// ★ MEASURE THIS BUILD, OR MEASURE NOTHING. Several worktrees run on one machine and a default port
+// belongs to whichever server started first — measured 2026-09-24 on :4173, where browser gates
+// reported confidently about a build nobody here had touched. 75 (EX_TEMPFAIL), not 1: the wrong
+// tree is a precondition, not a product defect, and the wave runner reports 75 as ⊘ rather than ✗.
+// A file:// target passes straight through — there is no server there to be wrong about.
+await requireThisTree(BASE, ROOT, 'FIXED-ANCHORING')
 const TK = process.env.MAPBOX_TOKEN ? `?tk=${process.env.MAPBOX_TOKEN}` : ''
 
 const DEEP = `(sel)=>{const out=[],seen=new Set();const w=(r)=>{if(!r||seen.has(r))return;seen.add(r);try{out.push(...r.querySelectorAll(sel))}catch(e){};for(const el of r.querySelectorAll('*'))if(el.shadowRoot)w(el.shadowRoot)};w(document);return out}`
diff --git a/internal/check-gospel-composed-filters.mjs b/internal/check-gospel-composed-filters.mjs
index 1dd239964..6df377008 100644
--- a/internal/check-gospel-composed-filters.mjs
+++ b/internal/check-gospel-composed-filters.mjs
@@ -29,11 +29,20 @@ import { chromium } from 'playwright'
 import { serveReaped } from './_serve-reaped.mjs'
 import { resolve, dirname } from 'node:path'
 import { fileURLToPath } from 'node:url'
+import { requireThisTree } from './_serves-this-tree.mjs'
 
 const HERE = dirname(fileURLToPath(import.meta.url))
 const PUBLIC = resolve(HERE, '../public')
 const PORT = Number(process.env.PORT || 5399)
 const BASE = process.env.BASE_URL || `http://127.0.0.1:${PORT}`
+const ROOT = resolve(dirname(fileURLToPath(import.meta.url)), '..')
+
+// ★ MEASURE THIS BUILD, OR MEASURE NOTHING. Several worktrees run on one machine and a default port
+// belongs to whichever server started first — measured 2026-09-24 on :4173, where browser gates
+// reported confidently about a build nobody here had touched. 75 (EX_TEMPFAIL), not 1: the wrong
+// tree is a precondition, not a product defect, and the wave runner reports 75 as ⊘ rather than ✗.
+// A file:// target passes straight through — there is no server there to be wrong about.
+await requireThisTree(BASE, ROOT, 'GOSPEL-COMPOSED-FILTERS')
 const PATHNAME = '/doxa-maps/gospel-resources/gospel-dashboard/index.html'
 
 let srv = null
diff --git a/internal/check-legend-info-localized.mjs b/internal/check-legend-info-localized.mjs
index 544d09022..c86204f15 100644
--- a/internal/check-legend-info-localized.mjs
+++ b/internal/check-legend-info-localized.mjs
@@ -32,11 +32,21 @@ import { chromium } from 'playwright'
 import { readFileSync, existsSync } from 'node:fs'
 import { join, dirname } from 'node:path'
 import { fileURLToPath } from 'node:url'
+import { requireThisTree } from './_serves-this-tree.mjs'
+import { resolve as _resolvePath, dirname as _dirnamePath } from 'node:path'
 
 const REPO = join(dirname(fileURLToPath(import.meta.url)), '..')
 const LOCALES = join(REPO, 'library/i18n/locales')
 
 const URL_ = process.argv[2] || process.env.LEGEND_URL
+const ROOT = _resolvePath(_dirnamePath(_fileURLToPath(import.meta.url)), '..')
+
+// ★ MEASURE THIS BUILD, OR MEASURE NOTHING. Several worktrees run on one machine and a default port
+// belongs to whichever server started first — measured 2026-09-24 on :4173, where browser gates
+// reported confidently about a build nobody here had touched. 75 (EX_TEMPFAIL), not 1: the wrong
+// tree is a precondition, not a product defect, and the wave runner reports 75 as ⊘ rather than ✗.
+// A file:// target passes straight through — there is no server there to be wrong about.
+await requireThisTree(URL_, ROOT, 'LEGEND-INFO-LOCALIZED')
 if (!URL_) {
   console.log('LEGEND-INFO-LOCALIZED: SKIP — no leaf url given.')
   console.log('  Pass one, or set LEGEND_URL. Serve the TREE ROOT (public/doxa-maps) and point')
diff --git a/internal/check-map-unmount-mid-init.mjs b/internal/check-map-unmount-mid-init.mjs
index 1b01e5f03..9b1c2c748 100644
--- a/internal/check-map-unmount-mid-init.mjs
+++ b/internal/check-map-unmount-mid-init.mjs
@@ -24,9 +24,20 @@
  * actually removed before release, the race was not staged and it exits 2, not 0.
  */
 import { chromium } from 'playwright'
+import { requireThisTree } from './_serves-this-tree.mjs'
+import { resolve as _resolvePath, dirname as _dirnamePath } from 'node:path'
+import { fileURLToPath as _fileURLToPath } from 'node:url'
 
 const i = process.argv.indexOf('--url')
 const BASE = (i > -1 ? process.argv[i + 1] : '').replace(/#.*$/, '')
+const ROOT = _resolvePath(_dirnamePath(_fileURLToPath(import.meta.url)), '..')
+
+// ★ MEASURE THIS BUILD, OR MEASURE NOTHING. Several worktrees run on one machine and a default port
+// belongs to whichever server started first — measured 2026-09-24 on :4173, where browser gates
+// reported confidently about a build nobody here had touched. 75 (EX_TEMPFAIL), not 1: the wrong
+// tree is a precondition, not a product defect, and the wave runner reports 75 as ⊘ rather than ✗.
+// A file:// target passes straight through — there is no server there to be wrong about.
+await requireThisTree(BASE, ROOT, 'MAP-UNMOUNT-MID-INIT')
 if (!BASE) { console.error('check-map-unmount-mid-init: pass --url <studio page>'); process.exit(2) }
 
 // Production map plugins that go through useMapInstance, opened by their studio key.
diff --git a/internal/check-mfe-two-tab.mjs b/internal/check-mfe-two-tab.mjs
index d03a54841..2d4e467b1 100644
--- a/internal/check-mfe-two-tab.mjs
+++ b/internal/check-mfe-two-tab.mjs
@@ -13,8 +13,19 @@
 //
 // Usage: node internal/check-mfe-two-tab.mjs <url> [expectedTabCount]
 import { chromium } from 'playwright'
+import { requireThisTree } from './_serves-this-tree.mjs'
+import { resolve as _resolvePath, dirname as _dirnamePath } from 'node:path'
+import { fileURLToPath as _fileURLToPath } from 'node:url'
 
 const URL = process.argv[2]
+const ROOT = _resolvePath(_dirnamePath(_fileURLToPath(import.meta.url)), '..')
+
+// ★ MEASURE THIS BUILD, OR MEASURE NOTHING. Several worktrees run on one machine and a default port
+// belongs to whichever server started first — measured 2026-09-24 on :4173, where browser gates
+// reported confidently about a build nobody here had touched. 75 (EX_TEMPFAIL), not 1: the wrong
+// tree is a precondition, not a product defect, and the wave runner reports 75 as ⊘ rather than ✗.
+// A file:// target passes straight through — there is no server there to be wrong about.
+await requireThisTree(URL, ROOT, 'MFE-TWO-TAB')
 if (!URL) { console.error('usage: check-mfe-two-tab.mjs <url> [tabs]'); process.exit(2) }
 const WANT_TABS = Number(process.argv[3] || 2)
 
diff --git a/internal/check-nav-reachable-mobile.mjs b/internal/check-nav-reachable-mobile.mjs
index 9ca2a3a67..7753cacca 100644
--- a/internal/check-nav-reachable-mobile.mjs
+++ b/internal/check-nav-reachable-mobile.mjs
@@ -37,10 +37,18 @@ import { readFileSync, existsSync } from 'node:fs'
 import { resolve, dirname, join } from 'node:path'
 import { fileURLToPath } from 'node:url'
 import { chromium } from 'playwright'
+import { requireThisTree } from './_serves-this-tree.mjs'
 
 const ROOT = resolve(dirname(fileURLToPath(import.meta.url)), '..')
 const MANIFEST = join(ROOT, 'public', 'doxa-maps', 'manifest.json')
 const BASE = process.env.BASE || 'http://127.0.0.1:4173/doxa-maps/'
+
+// ★ MEASURE THIS BUILD, OR MEASURE NOTHING. Several worktrees of this repo run on one machine and
+// a default port belongs to whichever server started first — measured 2026-09-24, :4173 was another
+// worktree's, and browser gates reported confidently on a build nobody here had touched. Exit 75
+// (EX_TEMPFAIL) rather than 1: pointing at the wrong tree is a precondition, not a product defect,
+// and the wave runner already reports 75 as ⊘ instead of ✗.
+await requireThisTree(BASE, ROOT, 'NAV-REACHABLE-MOBILE')
 // 414x896 = iPhone-class portrait, comfortably inside the layout's 760px breakpoint.
 const VIEWPORT = { width: Number(process.env.W || 414), height: Number(process.env.H || 896) }
 
diff --git a/internal/check-poster-degrades-honestly.mjs b/internal/check-poster-degrades-honestly.mjs
index 8ba1da8b1..0ff59870e 100644
--- a/internal/check-poster-degrades-honestly.mjs
+++ b/internal/check-poster-degrades-honestly.mjs
@@ -25,8 +25,19 @@
 //
 // Usage: node internal/check-poster-degrades-honestly.mjs <wallUrl> [zoneId]
 import { chromium } from 'playwright'
+import { requireThisTree } from './_serves-this-tree.mjs'
+import { resolve as _resolvePath, dirname as _dirnamePath } from 'node:path'
+import { fileURLToPath as _fileURLToPath } from 'node:url'
 
 const WALL = process.argv[2] || process.env.POSTER_WALL_URL
+const ROOT = _resolvePath(_dirnamePath(_fileURLToPath(import.meta.url)), '..')
+
+// ★ MEASURE THIS BUILD, OR MEASURE NOTHING. Several worktrees run on one machine and a default port
+// belongs to whichever server started first — measured 2026-09-24 on :4173, where browser gates
+// reported confidently about a build nobody here had touched. 75 (EX_TEMPFAIL), not 1: the wrong
+// tree is a precondition, not a product defect, and the wave runner reports 75 as ⊘ rather than ✗.
+// A file:// target passes straight through — there is no server there to be wrong about.
+await requireThisTree(WALL, ROOT, 'POSTER-DEGRADES-HONESTLY')
 if (!WALL) {
   console.log('POSTER-DEGRADES: SKIP — no wall url given.')
   console.log('  Serve the TREE ROOT (public/<name>), not public/, or assetsBase resolves')
diff --git a/internal/check-poster-print-fallback.mjs b/internal/check-poster-print-fallback.mjs
index 480b1f968..a9aaadb3a 100644
--- a/internal/check-poster-print-fallback.mjs
+++ b/internal/check-poster-print-fallback.mjs
@@ -24,12 +24,23 @@
 //
 // Usage: node internal/check-poster-print-fallback.mjs <wallUrl> [zoneId]
 import { chromium } from 'playwright'
+import { requireThisTree } from './_serves-this-tree.mjs'
+import { resolve as _resolvePath, dirname as _dirnamePath } from 'node:path'
+import { fileURLToPath as _fileURLToPath } from 'node:url'
 
 // SKIP, never fail, when the preconditions are absent. This gate needs a SERVED tree
 // that carries posters/<id>.html (posterSources:true or bundlePosters:true). The
 // default tree ships neither, and a clean checkout has no server at all — failing the
 // build on that would only teach people to disable the gate. It says what is missing.
 const WALL = process.argv[2] || process.env.POSTER_WALL_URL
+const ROOT = _resolvePath(_dirnamePath(_fileURLToPath(import.meta.url)), '..')
+
+// ★ MEASURE THIS BUILD, OR MEASURE NOTHING. Several worktrees run on one machine and a default port
+// belongs to whichever server started first — measured 2026-09-24 on :4173, where browser gates
+// reported confidently about a build nobody here had touched. 75 (EX_TEMPFAIL), not 1: the wrong
+// tree is a precondition, not a product defect, and the wave runner reports 75 as ⊘ rather than ✗.
+// A file:// target passes straight through — there is no server there to be wrong about.
+await requireThisTree(WALL, ROOT, 'POSTER-PRINT-FALLBACK')
 if (!WALL) {
   console.log('POSTER-PRINT-FALLBACK: SKIP — no wall url given.')
   console.log('  Pass one, or set POSTER_WALL_URL. Needs a tree built with posterSources:true')
diff --git a/internal/check-poster-raster.mjs b/internal/check-poster-raster.mjs
index f588d80cb..100ffce67 100644
--- a/internal/check-poster-raster.mjs
+++ b/internal/check-poster-raster.mjs
@@ -17,8 +17,19 @@
 // Usage: node internal/check-poster-raster.mjs [zoneId]
 //   PACKET_ORIGIN (default http://127.0.0.1:4898)
 import { chromium } from 'playwright'
+import { requireThisTree } from './_serves-this-tree.mjs'
+import { resolve as _resolvePath, dirname as _dirnamePath } from 'node:path'
+import { fileURLToPath as _fileURLToPath } from 'node:url'
 
 const ORIGIN = process.env.PACKET_ORIGIN || 'http://127.0.0.1:4898'
+const ROOT = _resolvePath(_dirnamePath(_fileURLToPath(import.meta.url)), '..')
+
+// ★ MEASURE THIS BUILD, OR MEASURE NOTHING. Several worktrees run on one machine and a default port
+// belongs to whichever server started first — measured 2026-09-24 on :4173, where browser gates
+// reported confidently about a build nobody here had touched. 75 (EX_TEMPFAIL), not 1: the wrong
+// tree is a precondition, not a product defect, and the wave runner reports 75 as ⊘ rather than ✗.
+// A file:// target passes straight through — there is no server there to be wrong about.
+await requireThisTree(ORIGIN, ROOT, 'POSTER-RASTER')
 const ZONE = process.argv[2] || 'laos'
 const HTML = `${ORIGIN}/library/scripts/posters/out/posters/${ZONE}.html`
 
diff --git a/internal/check-print-geometry.mjs b/internal/check-print-geometry.mjs
index 7ce5df5c2..642b94c98 100644
--- a/internal/check-print-geometry.mjs
+++ b/internal/check-print-geometry.mjs
@@ -14,8 +14,19 @@
 // Usage: node internal/check-print-geometry.mjs
 //   PACKET_ORIGIN (default http://127.0.0.1:4898) — a static server over the repo root
 import { chromium } from 'playwright'
+import { requireThisTree } from './_serves-this-tree.mjs'
+import { resolve as _resolvePath, dirname as _dirnamePath } from 'node:path'
+import { fileURLToPath as _fileURLToPath } from 'node:url'
 
 const ORIGIN = process.env.PACKET_ORIGIN || 'http://127.0.0.1:4898'
+const ROOT = _resolvePath(_dirnamePath(_fileURLToPath(import.meta.url)), '..')
+
+// ★ MEASURE THIS BUILD, OR MEASURE NOTHING. Several worktrees run on one machine and a default port
+// belongs to whichever server started first — measured 2026-09-24 on :4173, where browser gates
+// reported confidently about a build nobody here had touched. 75 (EX_TEMPFAIL), not 1: the wrong
+// tree is a precondition, not a product defect, and the wave runner reports 75 as ⊘ rather than ✗.
+// A file:// target passes straight through — there is no server there to be wrong about.
+await requireThisTree(ORIGIN, ROOT, 'PRINT-GEOMETRY')
 const API = process.env.PACKET_API || 'https://pray.doxa.life'
 const ISO3 = process.env.PACKET_ISO3 || 'LAO'
 
diff --git a/internal/check-scrim-covers-viewport.mjs b/internal/check-scrim-covers-viewport.mjs
index 26eb59480..24865c1dc 100644
--- a/internal/check-scrim-covers-viewport.mjs
+++ b/internal/check-scrim-covers-viewport.mjs
@@ -44,8 +44,19 @@
  * Exit: 0 all pass · 1 any fail · 2 dev server unreachable (a precondition, not a defect).
  */
 import { chromium } from 'playwright'
+import { requireThisTree } from './_serves-this-tree.mjs'
+import { resolve as _resolvePath, dirname as _dirnamePath } from 'node:path'
+import { fileURLToPath as _fileURLToPath } from 'node:url'
 
 const BASE = (process.env.DEV_URL || 'http://localhost:5173').replace(/\/+$/, '')
+const ROOT = _resolvePath(_dirnamePath(_fileURLToPath(import.meta.url)), '..')
+
+// ★ MEASURE THIS BUILD, OR MEASURE NOTHING. Several worktrees of this repo run on one machine and
+// a default port belongs to whichever server started first — measured 2026-09-24, :4173 was another
+// worktree's, and browser gates reported confidently on a build nobody here had touched. Exit 75
+// (EX_TEMPFAIL) rather than 1: pointing at the wrong tree is a precondition, not a product defect,
+// and the wave runner already reports 75 as ⊘ instead of ✗.
+await requireThisTree(BASE, ROOT, 'SCRIM-COVERS-VIEWPORT')
 const SELF_TEST = process.argv.includes('--self-test')
 const VW = 1280, VH = 900
 
diff --git a/internal/check-studio-every-plugin.mjs b/internal/check-studio-every-plugin.mjs
index da2731cfe..319ce116d 100644
--- a/internal/check-studio-every-plugin.mjs
+++ b/internal/check-studio-every-plugin.mjs
@@ -24,9 +24,20 @@
  * another worktree's tree — so this one refuses to guess.
  */
 import { chromium } from 'playwright'
+import { requireThisTree } from './_serves-this-tree.mjs'
+import { resolve as _resolvePath, dirname as _dirnamePath } from 'node:path'
+import { fileURLToPath as _fileURLToPath } from 'node:url'
 
 const i = process.argv.indexOf('--url')
 const URL_ = i > -1 ? process.argv[i + 1] : ''
+const ROOT = _resolvePath(_dirnamePath(_fileURLToPath(import.meta.url)), '..')
+
+// ★ MEASURE THIS BUILD, OR MEASURE NOTHING. Several worktrees run on one machine and a default port
+// belongs to whichever server started first — measured 2026-09-24 on :4173, where browser gates
+// reported confidently about a build nobody here had touched. 75 (EX_TEMPFAIL), not 1: the wrong
+// tree is a precondition, not a product defect, and the wave runner reports 75 as ⊘ rather than ✗.
+// A file:// target passes straight through — there is no server there to be wrong about.
+await requireThisTree(URL_, ROOT, 'STUDIO-EVERY-PLUGIN')
 if (!URL_) {
   console.error('check-studio-every-plugin: pass --url <studio page>, e.g. --url http://localhost:5299/')
   process.exit(2)
diff --git a/internal/verify-5-capabilities.mjs b/internal/verify-5-capabilities.mjs
index d1394d5b5..72670f6d2 100644
--- a/internal/verify-5-capabilities.mjs
+++ b/internal/verify-5-capabilities.mjs
@@ -33,9 +33,20 @@
  * Exits non-zero if any level fails, so it can gate a release.
  */
 import { chromium } from 'playwright'
+import { requireThisTree } from './_serves-this-tree.mjs'
+import { resolve as _resolvePath, dirname as _dirnamePath } from 'node:path'
+import { fileURLToPath as _fileURLToPath } from 'node:url'
 
 const GL=['--use-gl=swiftshader','--enable-unsafe-swiftshader','--ignore-gpu-blocklist','--enable-webgl','--no-sandbox']
 const B=(process.env.BASE || 'https://nuxtbase.app/plugin-assets/doxa-maps/').replace(/\/?$/,'/')
+const ROOT = _resolvePath(_dirnamePath(_fileURLToPath(import.meta.url)), '..')
+
+// ★ MEASURE THIS BUILD, OR MEASURE NOTHING. Several worktrees run on one machine and a default port
+// belongs to whichever server started first — measured 2026-09-24 on :4173, where browser gates
+// reported confidently about a build nobody here had touched. 75 (EX_TEMPFAIL), not 1: the wrong
+// tree is a precondition, not a product defect, and the wave runner reports 75 as ⊘ rather than ✗.
+// A file:// target passes straight through — there is no server there to be wrong about.
+await requireThisTree(B, ROOT, '5-CAPABILITIES')
 // capability = 5 - PROFILE_TIER (discover.mjs). One representative per level.
 const REPS=[
  // ★ CORRECTED 2026-09-20 by the manifest reconciliation added below, on its FIRST RUN.
diff --git a/internal/verify-map-paint.mjs b/internal/verify-map-paint.mjs
index 7993171cc..f13a39ee4 100644
--- a/internal/verify-map-paint.mjs
+++ b/internal/verify-map-paint.mjs
@@ -30,6 +30,9 @@
  * Exits non-zero if any leaf fails, so it can become a gate.
  */
 import { chromium } from 'playwright'
+import { requireThisTree } from './_serves-this-tree.mjs'
+import { resolve as _resolvePath, dirname as _dirnamePath } from 'node:path'
+import { fileURLToPath as _fileURLToPath } from 'node:url'
 
 // The SwiftShader launch. Without these a headless Chromium here has NO GL context at all.
 const GL_ARGS = [
@@ -41,6 +44,14 @@ const GL_ARGS = [
 ]
 
 const BASE = process.env.BASE || 'https://nuxtbase.app/plugin-assets/doxa-maps'
+const ROOT = _resolvePath(_dirnamePath(_fileURLToPath(import.meta.url)), '..')
+
+// ★ MEASURE THIS BUILD, OR MEASURE NOTHING. Several worktrees run on one machine and a default port
+// belongs to whichever server started first — measured 2026-09-24 on :4173, where browser gates
+// reported confidently about a build nobody here had touched. 75 (EX_TEMPFAIL), not 1: the wrong
+// tree is a precondition, not a product defect, and the wave runner reports 75 as ⊘ rather than ✗.
+// A file:// target passes straight through — there is no server there to be wrong about.
+await requireThisTree(BASE, ROOT, 'MAP-PAINT')
 // ★ WIDENED 2026-09-22 — 4 of 12 map profiles were covered, now 11.
 // The four originals were the ones that happened to be under investigation when this file was
 // written. Measuring the manifest showed 12 profiles carry isMap=true, so EIGHT painted leaves