diff --git a/plugins/voyage/tests/validators/brief-validator-annotation-fields.test.mjs b/plugins/voyage/tests/validators/brief-validator-annotation-fields.test.mjs
new file mode 100644
index 0000000..33fee13
--- /dev/null
+++ b/plugins/voyage/tests/validators/brief-validator-annotation-fields.test.mjs
@@ -0,0 +1,87 @@
+// tests/validators/brief-validator-annotation-fields.test.mjs
+// Pin forward-compat for v4.2 annotation frontmatter fields on brief.md.
+// Adding revision/source_annotations/annotation_digest/revision_reason must NOT
+// trigger BRIEF_UNKNOWN_FIELD or similar — validator is purely additive-tolerant
+// per source_findings precedent. No code change required; this test pins the policy.
+
+import { test } from 'node:test';
+import { strict as assert } from 'node:assert';
+import { validateBriefContent } from '../../lib/validators/brief-validator.mjs';
+
+const BASE_BRIEF = `---
+type: trekbrief
+brief_version: "2.0"
+created: 2026-05-09
+task: "Annotated revision for testing forward-compat"
+slug: ann-fwd-compat
+project_dir: .claude/projects/2026-05-09-ann-fwd-compat/
+research_topics: 0
+research_status: skipped
+auto_research: false
+interview_turns: 1
+source: interview
+---
+
+# Task: Annotated revision
+
+## Intent
+
+Why.
+
+## Goal
+
+What.
+
+## Success Criteria
+
+- Done.
+`;
+
+test('brief-validator forward-compat — baseline (no annotation fields) still valid', () => {
+  const r = validateBriefContent(BASE_BRIEF, { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('brief-validator forward-compat — accepts revision: 0', () => {
+  const t = BASE_BRIEF.replace('---\ninterview_turns: 1', '---\ninterview_turns: 1\nrevision: 0');
+  const r = validateBriefContent(t, { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('brief-validator forward-compat — accepts revision: 5', () => {
+  const t = BASE_BRIEF.replace('source: interview', 'source: interview\nrevision: 5');
+  const r = validateBriefContent(t, { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('brief-validator forward-compat — accepts source_annotations list-of-dict', () => {
+  const inject = `\nrevision: 1\nsource_annotations:\n  - id: ANN-0001\n    target_artifact: brief.md\n    target_anchor: intent\n    intent: change\n    comment: "tighten the intent paragraph"\n    timestamp: "2026-05-09T10:00:00Z"`;
+  const t = BASE_BRIEF.replace('source: interview', 'source: interview' + inject);
+  const r = validateBriefContent(t, { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('brief-validator forward-compat — accepts annotation_digest string', () => {
+  const t = BASE_BRIEF.replace('source: interview', 'source: interview\nrevision: 1\nannotation_digest: abc123def4567890');
+  const r = validateBriefContent(t, { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('brief-validator forward-compat — accepts revision_reason for non-additive revision', () => {
+  const t = BASE_BRIEF.replace('source: interview', 'source: interview\nrevision: 2\nrevision_reason: "restructured Goals section"');
+  const r = validateBriefContent(t, { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('brief-validator forward-compat — all 4 fields together still valid', () => {
+  const inject = `\nrevision: 3\nrevision_reason: "applied 5 annotations"\nannotation_digest: 0123456789abcdef\nsource_annotations:\n  - id: ANN-0001\n    target_artifact: brief.md\n    target_anchor: goal\n    intent: change`;
+  const t = BASE_BRIEF.replace('source: interview', 'source: interview' + inject);
+  const r = validateBriefContent(t, { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('brief-validator forward-compat — unrecognized future field still tolerated (forward-compat policy)', () => {
+  const t = BASE_BRIEF.replace('source: interview', 'source: interview\nfuture_v4_3_field: "anything"');
+  const r = validateBriefContent(t, { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
diff --git a/plugins/voyage/tests/validators/plan-validator-annotation-fields.test.mjs b/plugins/voyage/tests/validators/plan-validator-annotation-fields.test.mjs
new file mode 100644
index 0000000..6a74f5d
--- /dev/null
+++ b/plugins/voyage/tests/validators/plan-validator-annotation-fields.test.mjs
@@ -0,0 +1,79 @@
+// tests/validators/plan-validator-annotation-fields.test.mjs
+// Pin forward-compat for v4.2 annotation frontmatter fields on plan.md.
+// Adding revision/source_annotations/annotation_digest/revision_reason must NOT
+// trigger PLAN_UNKNOWN_FIELD or similar — validator is purely additive-tolerant
+// per source_findings precedent. No code change required; this test pins the policy.
+
+import { test } from 'node:test';
+import { strict as assert } from 'node:assert';
+import { validatePlanContent } from '../../lib/validators/plan-validator.mjs';
+
+const STEP_BLOCK = `### Step 1: Do thing
+
+- Files: a.ts
+- Manifest:
+  \`\`\`yaml
+  manifest:
+    expected_paths:
+      - a.ts
+    min_file_count: 1
+    commit_message_pattern: "^feat:"
+    bash_syntax_check: []
+    forbidden_paths: []
+    must_contain: []
+  \`\`\`
+`;
+
+const baseFm = (extra = '') => `---
+plan_version: "1.7"
+profile: balanced${extra}
+---
+
+# Plan
+
+## Implementation Plan
+
+${STEP_BLOCK}
+`;
+
+test('plan-validator forward-compat — baseline (no annotation fields) still valid', () => {
+  const r = validatePlanContent(baseFm(), { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('plan-validator forward-compat — accepts revision: 0', () => {
+  const r = validatePlanContent(baseFm('\nrevision: 0'), { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('plan-validator forward-compat — accepts revision: 5', () => {
+  const r = validatePlanContent(baseFm('\nrevision: 5'), { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('plan-validator forward-compat — accepts source_annotations list-of-dict', () => {
+  const inject = `\nrevision: 1\nsource_annotations:\n  - id: ANN-0001\n    target_artifact: plan.md\n    target_anchor: step-3\n    intent: change\n    comment: "reorder ahead of step 4"\n    timestamp: "2026-05-09T10:00:00Z"`;
+  const r = validatePlanContent(baseFm(inject), { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('plan-validator forward-compat — accepts annotation_digest string', () => {
+  const r = validatePlanContent(baseFm('\nrevision: 1\nannotation_digest: 0123456789abcdef'), { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('plan-validator forward-compat — accepts revision_reason', () => {
+  const r = validatePlanContent(baseFm('\nrevision: 2\nrevision_reason: "structural step reorder"'), { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('plan-validator forward-compat — all 4 fields together with source_findings', () => {
+  const inject = `\nrevision: 3\nrevision_reason: "applied 5 annotations"\nannotation_digest: abc1234567890def\nsource_annotations:\n  - id: ANN-0001\n    target_artifact: plan.md\n    target_anchor: step-3\n    intent: change\nsource_findings:\n  - 0123456789abcdef0123456789abcdef01234567`;
+  const r = validatePlanContent(baseFm(inject), { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('plan-validator forward-compat — unrecognized future field tolerated', () => {
+  const r = validatePlanContent(baseFm('\nfuture_v4_3_key: "any"'), { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
diff --git a/plugins/voyage/tests/validators/review-validator-annotation-fields.test.mjs b/plugins/voyage/tests/validators/review-validator-annotation-fields.test.mjs
new file mode 100644
index 0000000..d791509
--- /dev/null
+++ b/plugins/voyage/tests/validators/review-validator-annotation-fields.test.mjs
@@ -0,0 +1,89 @@
+// tests/validators/review-validator-annotation-fields.test.mjs
+// Pin forward-compat for v4.2 annotation frontmatter fields on review.md.
+// Adding revision/source_annotations/annotation_digest/revision_reason must NOT
+// trigger REVIEW_UNKNOWN_FIELD or similar — validator is purely additive-tolerant
+// per source_findings precedent. No code change required; this test pins the policy.
+
+import { test } from 'node:test';
+import { strict as assert } from 'node:assert';
+import { validateReviewContent } from '../../lib/validators/review-validator.mjs';
+
+const BASE_REVIEW = `---
+type: trekreview
+review_version: "1.0"
+created: 2026-05-09
+task: "Annotated revision forward-compat"
+slug: ann-fwd-compat
+project_dir: .claude/projects/2026-05-09-ann-fwd-compat/
+brief_path: .claude/projects/2026-05-09-ann-fwd-compat/brief.md
+scope_sha_start: abc123
+scope_sha_end: def456
+reviewed_files_count: 1
+findings: []
+---
+
+# Review
+
+## Executive Summary
+
+Verdict: ALLOW.
+
+## Coverage
+
+| File | Treatment | Reason |
+|------|-----------|--------|
+| lib/foo.mjs | deep-review | risk |
+
+## Remediation Summary
+
+None.
+`;
+
+test('review-validator forward-compat — baseline (no annotation fields) still valid', () => {
+  const r = validateReviewContent(BASE_REVIEW, { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('review-validator forward-compat — accepts revision: 0', () => {
+  const t = BASE_REVIEW.replace('findings: []', 'findings: []\nrevision: 0');
+  const r = validateReviewContent(t, { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('review-validator forward-compat — accepts revision: 5', () => {
+  const t = BASE_REVIEW.replace('findings: []', 'findings: []\nrevision: 5');
+  const r = validateReviewContent(t, { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('review-validator forward-compat — accepts source_annotations alongside source-style findings', () => {
+  const inject = `\nrevision: 1\nsource_annotations:\n  - id: ANN-0001\n    target_artifact: review.md\n    target_anchor: executive-summary\n    intent: question\n    comment: "wording is ambiguous"\n    timestamp: "2026-05-09T10:00:00Z"`;
+  const t = BASE_REVIEW.replace('findings: []', 'findings: []' + inject);
+  const r = validateReviewContent(t, { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('review-validator forward-compat — accepts annotation_digest string', () => {
+  const t = BASE_REVIEW.replace('findings: []', 'findings: []\nrevision: 1\nannotation_digest: 0123456789abcdef');
+  const r = validateReviewContent(t, { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('review-validator forward-compat — accepts revision_reason for non-additive revision', () => {
+  const t = BASE_REVIEW.replace('findings: []', 'findings: []\nrevision: 2\nrevision_reason: "removed coverage section"');
+  const r = validateReviewContent(t, { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('review-validator forward-compat — all 4 annotation fields together still valid', () => {
+  const inject = `\nrevision: 3\nrevision_reason: "applied 2 annotations"\nannotation_digest: 0123456789abcdef\nsource_annotations:\n  - id: ANN-0001\n    target_artifact: review.md\n    target_anchor: coverage\n    intent: change`;
+  const t = BASE_REVIEW.replace('findings: []', 'findings: []' + inject);
+  const r = validateReviewContent(t, { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});
+
+test('review-validator forward-compat — unrecognized future field tolerated', () => {
+  const t = BASE_REVIEW.replace('findings: []', 'findings: []\nfuture_v4_3_key: "any"');
+  const r = validateReviewContent(t, { strict: true });
+  assert.equal(r.valid, true, JSON.stringify(r.errors));
+});