diff --git a/.github/rpg-runtime/verify-release.py b/.github/rpg-runtime/verify-release.py
index 936c14741..cc27d1e06 100755
--- a/.github/rpg-runtime/verify-release.py
+++ b/.github/rpg-runtime/verify-release.py
@@ -10,7 +10,7 @@
 from pathlib import Path
 
 
-TAG = re.compile(r"^rpg-runtime-gae2602f1f83c-r[1-9][0-9]*(-rc\.[1-9][0-9]*)?$")
+TAG = re.compile(r"^retrom-core-gae2602f1f83c-r[1-9][0-9]*(-rc\.[1-9][0-9]*)?$")
 COMMIT = re.compile(r"^[0-9a-f]{40}$")
 BASELINE = "ae2602f1f83ca70d69b1ca8e66eb336141fe2a16"
 
@@ -37,7 +37,7 @@ def main() -> int:
     args = parser.parse_args()
     if TAG.fullmatch(args.tag) is None or COMMIT.fullmatch(args.commit) is None:
         raise SystemExit("RPG_RUNTIME_RELEASE_IDENTITY_INVALID")
-    if args.repository != "https://github.com/xxxsen/Butterscotch":
+    if args.repository != "https://github.com/retrom-project/Butterscotch":
         raise SystemExit("RPG_RUNTIME_RELEASE_REPOSITORY_INVALID")
 
     names = [
diff --git a/.github/rpg-runtime/verify-source.py b/.github/rpg-runtime/verify-source.py
index 3d016832b..6f844aa26 100755
--- a/.github/rpg-runtime/verify-source.py
+++ b/.github/rpg-runtime/verify-source.py
@@ -21,7 +21,7 @@ def main() -> int:
     manifest = json.loads((ROOT / "retrom-fork.json").read_text(encoding="utf-8"))
     expected = {
         "schemaVersion": 1,
-        "forkRepository": "https://github.com/xxxsen/Butterscotch",
+        "forkRepository": "https://github.com/retrom-project/Butterscotch",
         "defaultBranch": "retrom/gae2602f1f83c",
         "upstreamMirrorBranch": "main",
         "upstreams": [{
@@ -32,7 +32,7 @@ def main() -> int:
             "commit": BASELINE,
         }],
         "releaseTagPattern": (
-            r"^rpg-runtime-gae2602f1f83c-r[1-9][0-9]*"
+            r"^retrom-core-gae2602f1f83c-r[1-9][0-9]*"
             r"(-rc\.[1-9][0-9]*)?$"
         ),
         "adapterAbi": "butterscotch-checkpoint-v2",
diff --git a/.github/workflows/rpg-runtime-quality.yml b/.github/workflows/rpg-runtime-quality.yml
index 55d65541d..bf0283901 100644
--- a/.github/workflows/rpg-runtime-quality.yml
+++ b/.github/workflows/rpg-runtime-quality.yml
@@ -31,7 +31,7 @@ jobs:
           python3 .github/rpg-runtime/verify-release.py \
             --output "$RUNNER_TEMP/rpg-runtime-output" \
             --repository "https://github.com/$GITHUB_REPOSITORY" \
-            --tag rpg-runtime-gae2602f1f83c-r1-rc.1 \
+            --tag retrom-core-gae2602f1f83c-r1-rc.1 \
             --commit "$GITHUB_SHA"
       - name: Upload branch integration candidate
         uses: actions/upload-artifact@v4
diff --git a/.github/workflows/rpg-runtime-release.yml b/.github/workflows/rpg-runtime-release.yml
index 5193a72d4..48d45cbcf 100644
--- a/.github/workflows/rpg-runtime-release.yml
+++ b/.github/workflows/rpg-runtime-release.yml
@@ -2,7 +2,7 @@ name: RPG Runtime Release
 
 on:
   push:
-    tags: ["rpg-runtime-gae2602f1f83c-r*"]
+    tags: ["retrom-core-gae2602f1f83c-r*"]
 
 permissions:
   contents: write
@@ -22,7 +22,7 @@ jobs:
       - name: Validate release identity
         run: |
           set -euo pipefail
-          [[ "$GITHUB_REF_NAME" =~ ^rpg-runtime-gae2602f1f83c-r[1-9][0-9]*(-rc\.[1-9][0-9]*)?$ ]]
+          [[ "$GITHUB_REF_NAME" =~ ^retrom-core-gae2602f1f83c-r[1-9][0-9]*(-rc\.[1-9][0-9]*)?$ ]]
           git fetch --force origin \
             "refs/tags/$GITHUB_REF_NAME:refs/tags/$GITHUB_REF_NAME"
           test "$(git cat-file -t "refs/tags/$GITHUB_REF_NAME")" = tag
diff --git a/AGENTS.md b/AGENTS.md
index fd253d293..93dc8ebee 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -1,7 +1,7 @@
 # Retrom Butterscotch fork maintenance rules
 
 This fork builds the GameMaker: Studio browser runner consumed by
-`xxxsen/retrom-runtime`. It remains independent of Retrom application APIs,
+`retrom-project/retrom-runtime`. It remains independent of Retrom application APIs,
 databases, review workflows, credentials, and private games.
 
 ## Repository identity
@@ -58,9 +58,11 @@ databases, review workflows, credentials, and private games.
   `.github/rpg-runtime/verify-release.py` with a valid candidate identity.
 - PRs to `retrom/gae2602f1f83c` must pass
   `.github/workflows/rpg-runtime-quality.yml`.
-- Release tags are `rpg-runtime-gae2602f1f83c-rN`, with optional `-rc.N` only
+- Release tags are `retrom-core-gae2602f1f83c-rN`, with optional `-rc.N` only
   for integration candidates. Increment `rN` for any source, build, asset, or
   adapter-contract change on this baseline.
+- Existing `rpg-runtime-*` tags are immutable historical records. Never create
+  another tag in that retired namespace.
 - Tags are annotated and immutable. The tag workflow is the only supported way
   to build and publish the Web assets and `rpg-runtime-release.json`; never
   publish aliases such as `latest` or `stable`.
diff --git a/retrom-fork.json b/retrom-fork.json
index fe3c018f4..f93901e3c 100644
--- a/retrom-fork.json
+++ b/retrom-fork.json
@@ -1,6 +1,6 @@
 {
   "schemaVersion": 1,
-  "forkRepository": "https://github.com/xxxsen/Butterscotch",
+  "forkRepository": "https://github.com/retrom-project/Butterscotch",
   "defaultBranch": "retrom/gae2602f1f83c",
   "upstreamMirrorBranch": "main",
   "upstreams": [
@@ -12,7 +12,7 @@
       "commit": "ae2602f1f83ca70d69b1ca8e66eb336141fe2a16"
     }
   ],
-  "releaseTagPattern": "^rpg-runtime-gae2602f1f83c-r[1-9][0-9]*(-rc\\.[1-9][0-9]*)?$",
+  "releaseTagPattern": "^retrom-core-gae2602f1f83c-r[1-9][0-9]*(-rc\\.[1-9][0-9]*)?$",
   "adapterAbi": "butterscotch-checkpoint-v2",
   "releaseAssets": [
     "butterscotch.mjs",