diff --git a/.github/workflows/validate-schemas.yml b/.github/workflows/validate-schemas.yml
index f39bf64..183f70b 100644
--- a/.github/workflows/validate-schemas.yml
+++ b/.github/workflows/validate-schemas.yml
@@ -32,3 +32,6 @@ jobs:
 
       - name: Validate schemas and examples
         run: npm test
+
+      - name: Check spec-schema sync
+        run: npm run check:sync
diff --git a/spec/core/04-presentation-layers.md b/spec/core/04-presentation-layers.md
index 42e716d..c8271e7 100644
--- a/spec/core/04-presentation-layers.md
+++ b/spec/core/04-presentation-layers.md
@@ -997,7 +997,7 @@ If `matrix` is specified, it overrides all other transform properties.
 
 ## 17. Examples
 
-### 16.1 Minimal Continuous Presentation
+### 17.1 Minimal Continuous Presentation
 
 ```json
 {
@@ -1024,7 +1024,7 @@ If `matrix` is specified, it overrides all other transform properties.
 }
 ```
 
-### 16.2 Print-Ready Paginated Presentation
+### 17.2 Print-Ready Paginated Presentation
 
 ```json
 {
diff --git a/spec/extensions/README.md b/spec/extensions/README.md
index d1716a3..c03f1c3 100644
--- a/spec/extensions/README.md
+++ b/spec/extensions/README.md
@@ -108,4 +108,6 @@ When implementing Codex support, consider the following priority order:
   - Minor: New optional features, backward-compatible
   - Major: Breaking changes
 
+**Note:** Most extensions are at version 0.1 (initial draft). The Collaboration extension is at version 0.2 because it underwent breaking changes to its comment threading model during development. This version difference is intentional and reflects actual specification maturity.
+
 See individual extension READMEs for version history and migration notes.