feat: add missing-typography lint rule

README.md

@@ -262,6 +262,7 @@ The linter runs seven rules against a parsed DESIGN.md. Each rule produces findi
 | `orphaned-tokens` | warning | Color tokens defined but never referenced by any component |
 | `token-summary` | info | Summary of how many tokens are defined in each section |
 | `missing-sections` | info | Optional sections (spacing, rounded) absent when other tokens exist |
+| `missing-typography` | warning | Colors are defined but no typography tokens exist — agents will use default fonts |
 | `section-order` | warning | Sections appear out of the canonical order defined by the spec |
 
 ### Programmatic API

packages/cli/src/commands/spec.test.ts

@@ -75,6 +75,6 @@ describe('spec command', () => {
     const output = JSON.parse(outputStr);
     expect(output.spec).toBeDefined();
     expect(output.rules).toBeDefined();
-    expect(output.rules.length).toBe(7);
+    expect(output.rules.length).toBe(8);
   });
 });

packages/cli/src/linter/index.ts

@@ -28,6 +28,7 @@ export {
   orphanedTokens,
   tokenSummary,
   missingSections,
+  missingTypography,
 } from './linter/rules/index.js';
 export { contrastRatio } from './model/handler.js';
 export { TailwindEmitterHandler } from './tailwind/handler.js';

packages/cli/src/linter/linter/rules/index.ts

@@ -8,6 +8,7 @@ import { orphanedTokensRule } from './orphaned-tokens.js';
 import { tokenSummaryRule } from './token-summary.js';
 import { missingSectionsRule } from './missing-sections.js';
 import { sectionOrderRule } from './section-order.js';
+import { missingTypographyRule } from './missing-typography.js';
 
 /** The default set of lint rule descriptors, in order. */
 export const DEFAULT_RULE_DESCRIPTORS: RuleDescriptor[] = [
@@ -17,6 +18,7 @@ export const DEFAULT_RULE_DESCRIPTORS: RuleDescriptor[] = [
   orphanedTokensRule,
   tokenSummaryRule,
   missingSectionsRule,
+  missingTypographyRule,
   sectionOrderRule,
 ];
 
@@ -40,5 +42,6 @@ export { contrastCheck } from './contrast-ratio.js';
 export { orphanedTokens } from './orphaned-tokens.js';
 export { tokenSummary } from './token-summary.js';
 export { missingSections } from './missing-sections.js';
+export { missingTypography } from './missing-typography.js';
 export { sectionOrder } from './section-order.js';
 export type { LintRule } from './types.js';

packages/cli/src/linter/linter/rules/missing-typography.test.ts

@@ -0,0 +1,34 @@
+import { describe, it, expect } from 'bun:test';
+import { missingTypography } from './missing-typography.js';
+import { buildState } from './test-helpers.js';
+
+describe('missingTypography', () => {
+  it('emits warning when colors exist but no typography defined', () => {
+    const state = buildState({
+      colors: { primary: '#ff0000' },
+      // no typography
+    });
+    const findings = missingTypography(state);
+    expect(findings.length).toBe(1);
+    expect(findings[0]!.path).toBe('typography');
+    expect(findings[0]!.message).toMatch(/typography/i);
+  });
+
+  it('returns empty when typography IS defined', () => {
+    const state = buildState({
+      colors: { primary: '#ff0000' },
+      typography: {
+        'body-md': {
+          fontFamily: 'Inter',
+          fontSize: '16px',
+        },
+      },
+    });
+    expect(missingTypography(state)).toEqual([]);
+  });
+
+  it('returns empty when no colors defined (nothing to compare against)', () => {
+    const state = buildState({});
+    expect(missingTypography(state)).toEqual([]);
+  });
+});

packages/cli/src/linter/linter/rules/missing-typography.ts

@@ -0,0 +1,24 @@
+import type { DesignSystemState } from '../../model/spec.js';
+import type { RuleDescriptor, RuleFinding } from './types.js';
+
+/**
+ * Missing typography — warns when colors are defined but no typography tokens exist.
+ * Without typography tokens, agents will fall back to their own font choices,
+ * reducing the author's control over the design system's typographic identity.
+ */
+export function missingTypography(state: DesignSystemState): RuleFinding[] {
+  if (state.typography.size === 0 && state.colors.size > 0) {
+    return [{
+      path: 'typography',
+      message: "No typography tokens defined. Agents will use default font choices, reducing your control over the design system's typographic identity.",
+    }];
+  }
+  return [];
+}
+
+export const missingTypographyRule: RuleDescriptor = {
+  name: 'missing-typography',
+  severity: 'warning',
+  description: "Missing typography — warns when colors are defined but no typography tokens exist.",
+  run: missingTypography,
+};

packages/cli/src/linter/linter/rules/types.test.ts

@@ -26,7 +26,7 @@ describe('LintRule type', () => {
   });
 
   it('has all rules in DEFAULT_RULE_DESCRIPTORS', () => {
-    expect(DEFAULT_RULE_DESCRIPTORS.length).toBe(7);
+    expect(DEFAULT_RULE_DESCRIPTORS.length).toBe(8);
     DEFAULT_RULE_DESCRIPTORS.forEach((rule: RuleDescriptor) => {
       expect(rule.name).toBeTruthy();
       expect(rule.severity).toBeTruthy();