diff --git a/.gitignore b/.gitignore
index af9263d..97cc78a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,8 +9,14 @@ node_modules/
 # The bind mounts (PLAN.md §6, §7). Neither belongs in the repo: `brand/` is the
 # operator's override of the stock branding, and `data/` is the beta signup store.
 # `brand-default/` IS committed — it is baked into the image and must always be complete.
-brand/
-data/
+#
+# Both patterns are anchored with a leading slash, and that is load-bearing: an
+# unanchored `data/` matches a directory of that name at ANY depth, so it silently
+# swallowed `src/data/platform.json` — the one file the whole accuracy machinery reads.
+# The working tree still had it, so every local check passed; CI, cloning fresh, failed
+# on the missing module. Anchor anything meant to match only the repository root.
+/brand/
+/data/
 
 # Environment
 .env
diff --git a/src/data/platform.json b/src/data/platform.json
new file mode 100644
index 0000000..6c61e3e
--- /dev/null
+++ b/src/data/platform.json
@@ -0,0 +1,60 @@
+{
+  "$comment": [
+    "PLAN.md §12: one file holding every externally-sourced fact. Every page reads from",
+    "here, and NO version number is ever hardcoded in prose.",
+    "",
+    "`scripts/checkFacts.mjs` fetches the authority for each value below and fails the build",
+    "on any disagreement. When the platform moves, this repo goes red so someone updates the",
+    "site — that failure is the feature, exactly as in the Integration Kit's checkCoreApi.js.",
+    "",
+    "Do not edit a value here to make the check pass without also re-reading the page that",
+    "quotes it. §1's process rule exists because a stale local `main` is what produced the",
+    "wrong protocol number in the first place."
+  ],
+
+  "verifiedOn": "2026-08-19",
+
+  "protocol": 4,
+
+  "moduleApi": "1.6.0",
+
+  "bundle": {
+    "tag": "2026.08.19",
+    "sidecar": "v2.0.0",
+    "overlay": "v1.0.0",
+    "servuoMin": "57.4"
+  },
+
+  "releases": {
+    "link": "v2.0.0",
+    "installer": "v0.1.0",
+    "Module-uo": "v1.0.1",
+    "Android-app": "v0.5.0"
+  },
+
+  "$comment_website": [
+    "`website` publishes no releases at all — it ships as container images and is never",
+    "tagged. The site must never print a 'website version'; it refers to the platform by",
+    "bundle tag and Module API version instead. checkFacts.mjs asserts the releases list is",
+    "still empty, so the day that changes, this repo notices."
+  ],
+  "websiteHasReleases": false,
+
+  "moduleUoCapabilities": [
+    "shard",
+    "atlas",
+    "market",
+    "governors",
+    "guilds",
+    "houses",
+    "champs",
+    "cliloc"
+  ],
+
+  "androidApplicationId": "com.runicgateway.app",
+
+  "gitea": {
+    "base": "https://gitea.whitlocktech.com",
+    "org": "RunicGateway"
+  }
+}