diff --git a/.gitignore b/.gitignore
index 80a53c6..88be451 100644
--- a/.gitignore
+++ b/.gitignore
@@ -20,3 +20,5 @@ devenv.local.nix
 
 node_modules/
 appcast/dist/
+appcast/logs/
+appcast/report/
diff --git a/BuildScripts/appcast-report.sh b/BuildScripts/appcast-report.sh
new file mode 100755
index 0000000..4c24663
--- /dev/null
+++ b/BuildScripts/appcast-report.sh
@@ -0,0 +1,29 @@
+#!/bin/sh
+
+set -eu
+
+project_dir=$(CDPATH= cd -- "$(dirname -- "$0")/.." && pwd)
+logs_dir="$project_dir/appcast/logs"
+report_dir="$project_dir/appcast/report"
+account_id=$(aws sts get-caller-identity --query Account --output text)
+log_source="s3://tmpdisk-appcast-logs-prod/AWSLogs/$account_id/CloudFront/tmpdisk/"
+
+mkdir -p "$logs_dir" "$report_dir"
+aws s3 sync "$log_source" "$logs_dir" --exclude "*" --include "*.gz"
+
+log_paths=$(find "$logs_dir" -type f -name "*.gz" -print)
+if [ -z "$log_paths" ]; then
+  echo "no appcast logs found at $log_source" >&2
+  exit 1
+fi
+
+# CloudFront-generated object names contain no whitespace, so splitting the
+# newline-delimited find output produces one argument per log file.
+# shellcheck disable=SC2086
+"$project_dir/node_modules/.bin/twinkle" report \
+  "$project_dir/appcast/current.json" \
+  $log_paths \
+  --html "$report_dir/index.html" \
+  > "$report_dir/report.json"
+
+cat "$report_dir/report.json"
diff --git a/appcast/README.md b/appcast/README.md
index d144615..d6d4442 100644
--- a/appcast/README.md
+++ b/appcast/README.md
@@ -24,3 +24,13 @@ AWS_PROFILE=cg-prod npm run appcast:publish
 ```
 
 Publishing validates both manifests before any upload. Published objects are versioned in S3; CloudFront caches them for five minutes.
+
+## Offline metrics
+
+Download the retained CloudFront logs and generate local JSON and HTML reports:
+
+```sh
+AWS_PROFILE=cg-prod npm run appcast:report
+```
+
+Outputs are written to the gitignored `appcast/report/` directory. Raw logs remain local in `appcast/logs/`. The report counts update checks and estimates version adoption; it does not measure installations or completed downloads.
diff --git a/package-lock.json b/package-lock.json
index 05a7f77..976cf3f 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -6,13 +6,13 @@
     "": {
       "name": "tmpdisk-release-tools",
       "devDependencies": {
-        "twinkle-appcast": "https://github.com/cosmicglue-io/twinkle/archive/8fdf6eb74ca51ba9d5d587d3c94e1032b68c79eb.tar.gz"
+        "twinkle-appcast": "https://github.com/cosmicglue-io/twinkle/archive/e45e3be7f9bf684ee123c9b790e9850feef14ae0.tar.gz"
       }
     },
     "node_modules/twinkle-appcast": {
       "version": "0.1.0",
-      "resolved": "https://github.com/cosmicglue-io/twinkle/archive/8fdf6eb74ca51ba9d5d587d3c94e1032b68c79eb.tar.gz",
-      "integrity": "sha512-TL+w+dbtJryfgXOzD3lSE8ortQbhb2v3ZRmXeSD3sDAwkYYLji5Y6kIrd48ztPvrjSRrIcsqCYIF1AP/8u6XDA==",
+      "resolved": "https://github.com/cosmicglue-io/twinkle/archive/e45e3be7f9bf684ee123c9b790e9850feef14ae0.tar.gz",
+      "integrity": "sha512-u5rTK/BTWyfUPt/Bq06BHiOOr2YkxgjwlyuuN5YRMX40alxYgLYfwkz9wQo56CNwLaHJLeyEAPXWfMFkSuM5HQ==",
       "dev": true,
       "license": "Apache-2.0",
       "bin": {
diff --git a/package.json b/package.json
index 8024b87..0325bdb 100644
--- a/package.json
+++ b/package.json
@@ -3,9 +3,10 @@
   "private": true,
   "scripts": {
     "appcast:render": "sh BuildScripts/appcast.sh render all",
-    "appcast:publish": "sh BuildScripts/appcast.sh publish"
+    "appcast:publish": "sh BuildScripts/appcast.sh publish",
+    "appcast:report": "sh BuildScripts/appcast-report.sh"
   },
   "devDependencies": {
-    "twinkle-appcast": "https://github.com/cosmicglue-io/twinkle/archive/8fdf6eb74ca51ba9d5d587d3c94e1032b68c79eb.tar.gz"
+    "twinkle-appcast": "https://github.com/cosmicglue-io/twinkle/archive/e45e3be7f9bf684ee123c9b790e9850feef14ae0.tar.gz"
   }
 }