diff --git a/packages/cli/src/linter/model/handler.test.ts b/packages/cli/src/linter/model/handler.test.ts
index 0e0e05b..d3d6fda 100644
--- a/packages/cli/src/linter/model/handler.test.ts
+++ b/packages/cli/src/linter/model/handler.test.ts
@@ -506,4 +506,58 @@ describe('ModelHandler', () => {
       expect(btn?.properties.get('fontWeight')).toBe(600);
     });
   });
+
+  // ── Fix #75: non-string YAML scalars crash model builder ────────────
+  describe('non-string component property values (Issue #75)', () => {
+    it('does not crash when a component property is a float (opacity: 0.9)', () => {
+      const result = handler.execute(makeParsed({
+        colors: { primary: '#FF0000', 'on-primary': '#FFFFFF' },
+        components: {
+          button: {
+            backgroundColor: '{colors.primary}',
+            textColor: '{colors.on-primary}',
+            opacity: 0.9 as unknown as string,
+          },
+        },
+      }));
+      expect(result.findings.filter(f => f.severity === 'error')).toHaveLength(0);
+      const btn = result.designSystem.components.get('button');
+      expect(btn?.properties.get('opacity')).toBe(0.9);
+    });
+
+    it('does not crash when a component property is a boolean (visible: true)', () => {
+      const result = handler.execute(makeParsed({
+        components: {
+          banner: {
+            visible: true as unknown as string,
+          },
+        },
+      }));
+      expect(result.findings.filter(f => f.severity === 'error')).toHaveLength(0);
+      const banner = result.designSystem.components.get('banner');
+      expect(banner?.properties.get('visible')).toBe(true);
+    });
+
+    it('handles mixed number, boolean, and string props without crashing', () => {
+      const result = handler.execute(makeParsed({
+        colors: { primary: '#ff0000' },
+        components: {
+          card: {
+            backgroundColor: '{colors.primary}',
+            borderRadius: '8px',
+            fontWeight: 500 as unknown as string,
+            opacity: 0.85 as unknown as string,
+            visible: true as unknown as string,
+            disabled: false as unknown as string,
+          },
+        },
+      }));
+      expect(result.findings.filter(f => f.severity === 'error')).toHaveLength(0);
+      const card = result.designSystem.components.get('card');
+      expect(card?.properties.get('fontWeight')).toBe(500);
+      expect(card?.properties.get('opacity')).toBe(0.85);
+      expect(card?.properties.get('visible')).toBe(true);
+      expect(card?.properties.get('disabled')).toBe(false);
+    });
+  });
 });
\ No newline at end of file
diff --git a/packages/cli/src/linter/model/handler.ts b/packages/cli/src/linter/model/handler.ts
index 8cfd71c..004475d 100644
--- a/packages/cli/src/linter/model/handler.ts
+++ b/packages/cli/src/linter/model/handler.ts
@@ -177,12 +177,12 @@ export class ModelHandler implements ModelSpec {
           const unresolvedRefs: string[] = [];
 
           for (const [propName, rawValue] of Object.entries(props)) {
-            // Numeric values (e.g. fontWeight: 600, borderWidth: 1) are valid
-            // per spec and must be stored as-is. We check for 'number' here,
-            // but isTokenReference, isValidColor, and isParseableDimension
-            // are also guarded against other non-string types (like booleans)
-            // to prevent crashes like "raw.match is not a function".
-            if (typeof rawValue === 'number') {
+            // Non-string scalars (numbers, booleans) are valid YAML values
+            // that can appear in component properties (e.g. fontWeight: 600,
+            // visible: true, opacity: 0.9). Store them as-is rather than
+            // passing them to string-only helpers like isTokenReference or
+            // isValidColor, which would either silently coerce or crash.
+            if (typeof rawValue === 'number' || typeof rawValue === 'boolean') {
               properties.set(propName, rawValue);
             } else if (isTokenReference(rawValue)) {
               const refPath = rawValue.slice(1, -1);