diff --git a/src/lib/ai/generate-insight.ts b/src/lib/ai/generate-insight.ts
index 3cb1444f1..4b8fb939c 100644
--- a/src/lib/ai/generate-insight.ts
+++ b/src/lib/ai/generate-insight.ts
@@ -46,7 +46,10 @@ export interface GenerateInsightOutcome {
  * what went wrong on the first attempt. Includes the violated zod
  * issues verbatim (truncated to 1KB) so the model can self-correct.
  */
-function buildRetryCorrectionMessage(reason: string, details: string): string {
+export function buildRetryCorrectionMessage(
+  reason: string,
+  details: string,
+): string {
   return `
 Your previous response did not satisfy the required JSON schema.
 Reason: ${reason}
diff --git a/src/lib/insights/__tests__/comprehensive-json-retry.test.ts b/src/lib/insights/__tests__/comprehensive-json-retry.test.ts
new file mode 100644
index 000000000..047525350
--- /dev/null
+++ b/src/lib/insights/__tests__/comprehensive-json-retry.test.ts
@@ -0,0 +1,128 @@
+/**
+ * v1.18.7 (MEDIUM-5) — comprehensive JSON-retry robustness.
+ *
+ * The comprehensive path used to fail cold to `invalid-json` on a first-pass
+ * parse miss. It now reuses `buildRetryCorrectionMessage` for ONE corrective
+ * retry before declaring failure. These tests pin: a first-pass miss followed
+ * by a valid retry succeeds; two misses fail; and a first-pass success runs
+ * no retry.
+ */
+import { describe, it, expect, vi, beforeEach } from "vitest";
+
+const findUnique = vi.fn();
+const userUpdate = vi.fn();
+const resolveProviderChain = vi.fn();
+const resolveProvider = vi.fn();
+const runRawCompletionWithFallback = vi.fn();
+const extractFeatures = vi.fn();
+
+vi.mock("@/lib/db", () => ({
+  prisma: {
+    user: {
+      findUnique: (...a: unknown[]) => findUnique(...a),
+      update: (...a: unknown[]) => userUpdate(...a),
+    },
+    auditLog: { deleteMany: vi.fn() },
+  },
+}));
+vi.mock("@/lib/ai/provider", () => ({
+  resolveProviderChain: (...a: unknown[]) => resolveProviderChain(...a),
+  resolveProvider: (...a: unknown[]) => resolveProvider(...a),
+}));
+vi.mock("@/lib/ai/provider-runner", () => ({
+  AllProvidersFailedError: class extends Error {},
+  runRawCompletionWithFallback: (...a: unknown[]) =>
+    runRawCompletionWithFallback(...a),
+}));
+vi.mock("@/lib/insights/features", () => ({
+  FeaturesPayloadTooLargeError: class extends Error {
+    sizeBytes = 0;
+  },
+  extractFeatures: (...a: unknown[]) => extractFeatures(...a),
+}));
+vi.mock("@/lib/insights/glp1-plateau", () => ({
+  detectGlp1Plateau: vi.fn(async () => null),
+  buildGlp1PlateauPrompt: vi.fn(() => ""),
+}));
+vi.mock("@/lib/ai/coach/about-me", () => ({
+  getSelfContextTextForUser: vi.fn(async () => null),
+  buildAboutMeInsightBlock: vi.fn(() => ""),
+}));
+vi.mock("@/lib/cache/invalidate", () => ({
+  invalidateUserInsights: vi.fn(),
+}));
+
+import { generateComprehensiveInsight } from "../comprehensive-generate";
+
+const FEATURES = { weight: { count: 12, latest: 81.4, mean30: 82.1 } };
+
+beforeEach(() => {
+  vi.clearAllMocks();
+  resolveProviderChain.mockResolvedValue([
+    { providerType: "openai", instance: {} },
+  ]);
+  resolveProvider.mockResolvedValue({ type: "none" });
+  extractFeatures.mockResolvedValue(FEATURES);
+  userUpdate.mockResolvedValue({});
+  // No cached text / hash → always runs a full generation (no gate hit).
+  findUnique.mockResolvedValue({
+    insightsPrivacyMode: "aggregated",
+    insightsCachedAt: null,
+    insightsCachedText: null,
+    insightsExcludeMetrics: [],
+    insightsSnapshotHash: null,
+    insightsBriefingRerollDate: null,
+  });
+});
+
+const VALID = JSON.stringify({ dailyBriefing: { paragraph: "ok" } });
+
+describe("comprehensive JSON-retry", () => {
+  it("recovers via one corrective retry after a first-pass JSON miss", async () => {
+    runRawCompletionWithFallback
+      .mockResolvedValueOnce({
+        result: { content: "I'm sorry, here is the data:", tokensUsed: 5, model: "m" },
+        workingProvider: { providerType: "openai" },
+        fallbackHops: [],
+      })
+      .mockResolvedValueOnce({
+        result: { content: VALID, tokensUsed: 10, model: "m" },
+        workingProvider: { providerType: "openai" },
+        fallbackHops: [],
+      });
+
+    const outcome = await generateComprehensiveInsight("u1", { locale: "de" });
+
+    expect(outcome).toEqual({ status: "generated", providerType: "openai" });
+    expect(runRawCompletionWithFallback).toHaveBeenCalledTimes(2);
+    // The retry call appends the correction to the user prompt.
+    const retryParams = runRawCompletionWithFallback.mock.calls[1][0].params;
+    expect(retryParams.userPrompt).toContain("did not satisfy the required");
+  });
+
+  it("fails with invalid-json when both attempts miss", async () => {
+    runRawCompletionWithFallback.mockResolvedValue({
+      result: { content: "still not json", tokensUsed: 5, model: "m" },
+      workingProvider: { providerType: "openai" },
+      fallbackHops: [],
+    });
+
+    const outcome = await generateComprehensiveInsight("u1", { locale: "de" });
+
+    expect(outcome).toEqual({ status: "failed", reason: "invalid-json" });
+    expect(runRawCompletionWithFallback).toHaveBeenCalledTimes(2);
+  });
+
+  it("runs no retry when the first pass is valid", async () => {
+    runRawCompletionWithFallback.mockResolvedValue({
+      result: { content: VALID, tokensUsed: 10, model: "m" },
+      workingProvider: { providerType: "openai" },
+      fallbackHops: [],
+    });
+
+    const outcome = await generateComprehensiveInsight("u1", { locale: "de" });
+
+    expect(outcome).toEqual({ status: "generated", providerType: "openai" });
+    expect(runRawCompletionWithFallback).toHaveBeenCalledTimes(1);
+  });
+});
diff --git a/src/lib/insights/comprehensive-generate.ts b/src/lib/insights/comprehensive-generate.ts
index 97c1b2ea9..7f263103f 100644
--- a/src/lib/insights/comprehensive-generate.ts
+++ b/src/lib/insights/comprehensive-generate.ts
@@ -34,6 +34,7 @@ import {
   type ComparisonSnapshot,
 } from "@/lib/ai/prompts/insight-system-prompt";
 import { buildSystemPromptWithReferences } from "@/lib/ai/prompts/insight-generator";
+import { buildRetryCorrectionMessage } from "@/lib/ai/generate-insight";
 import {
   buildAboutMeInsightBlock,
   getSelfContextTextForUser,
@@ -234,6 +235,28 @@ async function rerollBriefingParagraph(args: {
   return { text: JSON.stringify(merged), providerType };
 }
 
+/**
+ * Parse + (best-effort) validate a comprehensive provider reply. Returns the
+ * parsed payload (validated when it matches `insightResultSchema`, else the
+ * raw object so the richer optional blocks survive), or null when the reply
+ * is not valid JSON even after fence-stripping. Null signals the caller to
+ * run its one corrective retry.
+ */
+function parseComprehensiveResult(
+  content: string,
+): InsightResult | Record<string, unknown> | null {
+  let parsed: unknown;
+  try {
+    parsed = JSON.parse(stripJsonFences(content));
+  } catch {
+    return null;
+  }
+  const validated = insightResultSchema.safeParse(parsed);
+  return validated.success
+    ? validated.data
+    : (parsed as Record<string, unknown>);
+}
+
 /**
  * Comparison-snapshot builder — shared with the on-demand route. Returns
  * null when the user's comparison toggle is off (most users), so the
@@ -856,16 +879,45 @@ export async function generateComprehensiveInsight(
     return { status: "failed", reason: "provider-error" };
   }
 
-  let insights: InsightResult | Record<string, unknown>;
-  try {
-    // Anthropic + local have no native JSON mode, so a ```json-fenced or
-    // sentence-prefixed reply would otherwise fail the whole generation.
-    // Strip the fence before parsing; clean JSON passes through unchanged.
-    const parsed = JSON.parse(stripJsonFences(result.content));
-    const validated = insightResultSchema.safeParse(parsed);
-    insights = validated.success ? validated.data : parsed;
-  } catch {
-    return { status: "failed", reason: "invalid-json" };
+  // Anthropic + local have no native JSON mode, so a ```json-fenced or
+  // sentence-prefixed reply would otherwise fail the whole generation.
+  // Strip the fence before parsing; clean JSON passes through unchanged.
+  let insights = parseComprehensiveResult(result.content);
+  if (insights === null) {
+    // v1.18.7 (MEDIUM-5) — one corrective retry before declaring failure,
+    // reusing the same `buildRetryCorrectionMessage` the strict insight
+    // wrapper uses next door. The comprehensive path previously failed cold
+    // to `invalid-json` on a first-pass miss even though the recovery helper
+    // sat right there. The retry appends the correction to the user prompt
+    // and re-runs the chain once.
+    annotate({
+      action: { name: "insights.generate.json_retry" },
+      meta: { locale },
+    });
+    try {
+      const retry = await runRawCompletionWithFallback({
+        userId,
+        providers: chain,
+        params: {
+          systemPrompt,
+          userPrompt: `${userPrompt}\n\n${buildRetryCorrectionMessage(
+            "Response was not valid JSON",
+            "The previous reply could not be parsed as a JSON object.",
+          )}`,
+          temperature: AI_BUDGETS.comprehensive.temperature,
+          maxTokens: AI_BUDGETS.comprehensive.maxTokens,
+          responseFormat: "json",
+        },
+      });
+      result = retry.result;
+      workingProviderType = retry.workingProvider.providerType;
+    } catch {
+      return { status: "failed", reason: "invalid-json" };
+    }
+    insights = parseComprehensiveResult(result.content);
+    if (insights === null) {
+      return { status: "failed", reason: "invalid-json" };
+    }
   }
 
   // v1.9.0 — the caller abandoned this generation (its bounded timeout