diff --git a/.Jules/vantage.md b/.Jules/vantage.md
index e63beebe..6e9850b5 100644
--- a/.Jules/vantage.md
+++ b/.Jules/vantage.md
@@ -13,3 +13,5 @@
 ## 2026-05-15 - Standardizing Telemetry Resilience and Verifying Infrastructure Mocks | **Learning:** Telemetry must capture the full context of unknown errors via `String(e)` to avoid masking failure signals, and re-exporting mocks requires explicit execution to register in coverage reports. | **Action:** Updated `src/utils/github-releases.ts` to use `String(error)` in catch blocks and added an `exerciseMock` helper to `src/__tests__/mocks/astro-zod.ts` to achieve 100% coverage.
 
 ## 2026-05-20 - Hardening Telemetry Verification and Refining Stream Types | **Learning:** Index-based assertions in telemetry tests are brittle; using `.find()` ensures robust verification. Standardizing on `String(error)` across all API catch blocks prevents context loss during failure events. | **Action:** Refactored `chat-api.test.ts` and `github-releases.test.ts` to use search-based spy assertions, and added explicit return types to `chat-stream.ts` to resolve Astro compiler hints.
+
+## 2026-05-24 - Comprehensive Unit Testing for Visitor Changelog Formatting | **Learning:** Single-pass Edge transformations require dedicated unit tests covering edge cases like empty inputs, internal agent filtering, and fallback formatting to prevent silent regressions in SSR release streams. | **Action:** Added `src/utils/visitor-changelog.test.ts` to test `toVisitorChangelogTitle`, `stripChangelogChrome`, `toVisitorReleaseBody`, and `toVisitorRelease`.
diff --git a/src/utils/visitor-changelog.test.ts b/src/utils/visitor-changelog.test.ts
new file mode 100644
index 00000000..ee4715fb
--- /dev/null
+++ b/src/utils/visitor-changelog.test.ts
@@ -0,0 +1,118 @@
+import { describe, expect, it } from 'vitest';
+
+import {
+  stripChangelogChrome,
+  toVisitorChangelogTitle,
+  toVisitorRelease,
+  toVisitorReleaseBody,
+} from './visitor-changelog';
+
+describe('visitor-changelog utilities', () => {
+  describe('stripChangelogChrome', () => {
+    it('handles empty and whitespace-only strings', () => {
+      expect(stripChangelogChrome('')).toBe('');
+      expect(stripChangelogChrome('   ')).toBe('');
+    });
+
+    it('strips commit SHA, conventional commit prefix, and PR suffix', () => {
+      expect(stripChangelogChrome('a1b2c3d feat(ui): add new button (#123)')).toBe(
+        'add new button'
+      );
+      expect(stripChangelogChrome('fix: resolve alignment issue (#456)')).toBe(
+        'resolve alignment issue'
+      );
+      expect(stripChangelogChrome('chore(deps): update packages')).toBe('update packages');
+    });
+
+    it('collapses multiple whitespace characters', () => {
+      expect(stripChangelogChrome('feat:   multiple   spaces  ')).toBe('multiple spaces');
+    });
+  });
+
+  describe('toVisitorChangelogTitle', () => {
+    it('returns empty string for empty input', () => {
+      expect(toVisitorChangelogTitle('')).toBe('');
+      expect(toVisitorChangelogTitle('   ')).toBe('');
+    });
+
+    it('looks up known PR numbers', () => {
+      expect(toVisitorChangelogTitle('feat: add a live RSS feed (#520)')).toBe(
+        'RSS feed of the work'
+      );
+    });
+
+    it('looks up known subjects when PR number is omitted', () => {
+      expect(toVisitorChangelogTitle('add a live RSS feed for the work')).toBe(
+        'RSS feed of the work'
+      );
+    });
+
+    it('formats unknown commits by stripping chrome and capitalizing the first letter', () => {
+      expect(
+        toVisitorChangelogTitle('f1a2b3c feat(nav): improve keyboard accessibility (#999)')
+      ).toBe('Improve keyboard accessibility');
+    });
+
+    it('returns already clean visitor titles as-is', () => {
+      expect(toVisitorChangelogTitle('Clean visitor title without chrome')).toBe(
+        'Clean visitor title without chrome'
+      );
+    });
+
+    it('falls back gracefully when chrome stripping leaves an empty subject', () => {
+      expect(toVisitorChangelogTitle('a1b2c3d feat:')).toBe('Feat:');
+    });
+  });
+
+  describe('toVisitorReleaseBody', () => {
+    it('returns empty string for empty body', () => {
+      expect(toVisitorReleaseBody('')).toBe('');
+      expect(toVisitorReleaseBody('   ')).toBe('');
+    });
+
+    it('converts bullet point lines into visitor titles', () => {
+      const input =
+        '- 520 feat: add a live RSS feed for the work (#520)\n* 518 feat: add a working web app manifest (#518)';
+      const output = toVisitorReleaseBody(input);
+      expect(output).toBe('- RSS feed of the work\n- Web app manifest');
+    });
+
+    it('filters out internal agent or tool items from bullet lists', () => {
+      const input =
+        '- feat: add public feature\n- chore(jules): internal sync\n- refactor(engine): internal logic';
+      const output = toVisitorReleaseBody(input);
+      expect(output).toBe('- Add public feature');
+    });
+
+    it('falls back to toVisitorChangelogTitle if body contains no bullet items', () => {
+      const input = 'a1b2c3d feat: add a live RSS feed for the work (#520)';
+      expect(toVisitorReleaseBody(input)).toBe('RSS feed of the work');
+    });
+
+    it('falls back to toVisitorChangelogTitle if all bullet items are filtered as internal', () => {
+      const input = '- chore(jules): internal update\n- refactor(engine): backend tweak';
+      expect(toVisitorReleaseBody(input)).toBe(
+        '- chore(jules): internal update\n- refactor(engine): backend tweak'
+      );
+    });
+  });
+
+  describe('toVisitorRelease', () => {
+    it('transforms the release body while preserving other release properties', () => {
+      const release = {
+        version: 'v1.0.0',
+        publishedAt: '2026-05-01T12:00:00Z',
+        url: 'https://example.com/release/v1.0.0',
+        body: '- 520 feat: add a live RSS feed for the work (#520)',
+      };
+
+      const result = toVisitorRelease(release);
+      expect(result).toEqual({
+        version: 'v1.0.0',
+        publishedAt: '2026-05-01T12:00:00Z',
+        url: 'https://example.com/release/v1.0.0',
+        body: '- RSS feed of the work',
+      });
+    });
+  });
+});