diff --git a/.oxfmtrc.json b/.oxfmtrc.json
index 4920f0d4..5e5f8271 100644
--- a/.oxfmtrc.json
+++ b/.oxfmtrc.json
@@ -21,7 +21,14 @@
     ".serena/project.yml",
     ".github/copilot-instructions.md",
     ".github/instructions/**",
-    "rulesync.jsonc",
     "rulesync.local.jsonc"
+  ],
+  "overrides": [
+    {
+      "files": ["**/*.json", "**/*.jsonc"],
+      "options": {
+        "trailingComma": "none"
+      }
+    }
   ]
 }
diff --git a/rulesync.jsonc b/rulesync.jsonc
index 68b356e5..047f769b 100644
--- a/rulesync.jsonc
+++ b/rulesync.jsonc
@@ -7,32 +7,32 @@
     "copilot": {
       "rules": {
         "ruleDiscoveryMode": "explicit",
-        "includeLocalRoot": false,
+        "includeLocalRoot": false
       },
       "commands": true,
       "mcp": false,
       "subagents": true,
-      "skills": true,
+      "skills": true
     },
     "claudecode": {
       "rules": true,
       "commands": true,
       "mcp": true,
       "subagents": true,
-      "skills": true,
+      "skills": true
     },
     "opencode": {
       "rules": true,
       "commands": true,
       "mcp": true,
       "subagents": true,
-      "skills": true,
+      "skills": true
     },
     "takt": {
       "rules": true,
       "commands": true,
       "subagents": true,
-      "skills": true,
+      "skills": true
     }
   },
 
@@ -50,5 +50,5 @@
 
   // When true (default), `rulesync gitignore` only emits entries for the
   // tools listed in `targets`.
-  "gitignoreTargetsOnly": true,
+  "gitignoreTargetsOnly": true
 }