diff --git a/marketplaces/default.json b/marketplaces/default.json
index 1120ee86..5af0eaf8 100644
--- a/marketplaces/default.json
+++ b/marketplaces/default.json
@@ -10,6 +10,17 @@
         "pluginRoot": "./skills"
     },
     "plugins": [
+        {
+            "name": "test-marker-372",
+            "source": "./test-marker-372",
+            "description": "[TEST-BRANCH-372-MARKER] Test marker to verify extensions branch selection is working",
+            "category": "testing",
+            "keywords": [
+                "test",
+                "marker",
+                "branch"
+            ]
+        },
         {
             "name": "add-skill",
             "source": "./add-skill",
diff --git a/skills/github/SKILL.md b/skills/github/SKILL.md
index 4d22785b..c8a07f60 100644
--- a/skills/github/SKILL.md
+++ b/skills/github/SKILL.md
@@ -1,11 +1,13 @@
 ---
 name: github
-description: Interact with GitHub repositories, pull requests, issues, and workflows using the GITHUB_TOKEN environment variable and GitHub CLI. Use when working with code hosted on GitHub or managing GitHub resources.
+description: "[TEST-BRANCH-372-MARKER] Interact with GitHub repositories, pull requests, issues, and workflows using the GITHUB_TOKEN environment variable and GitHub CLI. Use when working with code hosted on GitHub or managing GitHub resources."
 triggers:
 - github
 - git
 ---
 
+**🔍 TEST MARKER FOR ISSUE #372: If you see this message, the extensions branch selection feature is working! This skill was loaded from the test branch `test/extensions-branch-selection-372` instead of main. 🔍**
+
 You have access to an environment variable, `GITHUB_TOKEN`, which allows you to interact with
 the GitHub API.
 
diff --git a/skills/test-marker-372/SKILL.md b/skills/test-marker-372/SKILL.md
new file mode 100644
index 00000000..8d35b60c
--- /dev/null
+++ b/skills/test-marker-372/SKILL.md
@@ -0,0 +1,27 @@
+---
+name: test-marker-372
+description: "[TEST-BRANCH-372-MARKER] This is a test marker skill to verify extensions branch selection is working"
+triggers:
+- python
+- fix
+- test
+- error
+- bug
+- issue
+---
+
+# 🔍🔍🔍 TEST MARKER FOR ISSUE #372 🔍🔍🔍
+
+**⚠️ IMPORTANT: If you see this message, the extensions branch selection feature is working! ⚠️**
+
+This skill was loaded from the test branch `test/extensions-branch-selection-372` instead of main.
+
+**This confirms:**
+✅ The `extensions_branch` parameter was passed correctly
+✅ The `EXTENSIONS_REF` environment variable was set
+✅ The SDK loaded extensions from the specified branch
+✅ The feature is working end-to-end!
+
+**DO NOT use this skill for anything - it's only a test marker.**
+
+# 🔍🔍🔍 END TEST MARKER 🔍🔍🔍