diff --git a/apps/web/src/lib/composerContextRecords.test.ts b/apps/web/src/lib/composerContextRecords.test.ts
index dff3f83a59554..9ac0eaf03d086 100644
--- a/apps/web/src/lib/composerContextRecords.test.ts
+++ b/apps/web/src/lib/composerContextRecords.test.ts
@@ -267,6 +267,12 @@ describe("composerContextRecords", () => {
     expect(restored.elements[0]?.id).toBe("el_1");
   });
 
+  it("clamps an oversized annotation comment so the record still decodes", () => {
+    const record = previewAnnotationContextRecord({ ...annotation, comment: "c".repeat(8_001) });
+    expect(record.comment.endsWith("… truncated …")).toBe(true);
+    expect(decodeMessageContext({ version: 1, records: [record] }).records).toEqual([record]);
+  });
+
   it("removes an expired terminal chip by its kind-scoped id, not the producer id", () => {
     const context = {
       id: "term-1",
diff --git a/apps/web/src/lib/composerContextRecords.ts b/apps/web/src/lib/composerContextRecords.ts
index a7ae316b5c865..2c107349de525 100644
--- a/apps/web/src/lib/composerContextRecords.ts
+++ b/apps/web/src/lib/composerContextRecords.ts
@@ -3,6 +3,7 @@ import {
   sourceControlClients,
 } from "@t3tools/client-runtime/source-control-clients";
 import {
+  COMPOSER_CONTEXT_PREVIEW_COMMENT_MAX_CHARS,
   COMPOSER_CONTEXT_REVIEW_DIFF_MAX_CHARS,
   COMPOSER_CONTEXT_REVIEW_TEXT_MAX_CHARS,
   COMPOSER_CONTEXT_TERMINAL_TEXT_MAX_CHARS,
@@ -301,7 +302,10 @@ export function previewAnnotationContextRecord(
     annotationId: annotation.id,
     pageUrl: annotation.pageUrl,
     pageTitle: annotation.pageTitle,
-    comment: annotation.comment.trim(),
+    comment: clampContextText(
+      annotation.comment.trim(),
+      COMPOSER_CONTEXT_PREVIEW_COMMENT_MAX_CHARS,
+    ),
     targetSummary: previewAnnotationTargetSummary(annotation),
     styleChanges: annotation.styleChanges.map(
       (change) => `${change.property}: ${change.previousValue || "(unset)"} → ${change.value}`,
diff --git a/packages/contracts/src/composerContext.ts b/packages/contracts/src/composerContext.ts
index d30ab84b73880..982202b05bc30 100644
--- a/packages/contracts/src/composerContext.ts
+++ b/packages/contracts/src/composerContext.ts
@@ -42,7 +42,7 @@ const COMPOSER_CONTEXT_ELEMENT_HTML_MAX_CHARS = 8_000;
 const COMPOSER_CONTEXT_ELEMENT_STYLES_MAX_CHARS = 8_000;
 export const COMPOSER_CONTEXT_REVIEW_TEXT_MAX_CHARS = 16_000;
 export const COMPOSER_CONTEXT_REVIEW_DIFF_MAX_CHARS = 32_000;
-const COMPOSER_CONTEXT_PREVIEW_COMMENT_MAX_CHARS = 8_000;
+export const COMPOSER_CONTEXT_PREVIEW_COMMENT_MAX_CHARS = 8_000;
 
 export const ComposerContextId = TrimmedNonEmptyString.check(
   Schema.isMaxLength(CONTEXT_ID_MAX_CHARS),