diff --git a/server/_core/embeddings/degradation-alert.ts b/server/_core/embeddings/degradation-alert.ts
new file mode 100644
index 00000000..50a2d45f
--- /dev/null
+++ b/server/_core/embeddings/degradation-alert.ts
@@ -0,0 +1,62 @@
+/**
+ * Silent-degradation detection for clinical search.
+ *
+ * Two failure modes must never reach a paramedic silently:
+ *  1. Semantic search degrades to keyword-only (embedding 403 / invalid key /
+ *     circuit open) — results still return but retrieval quality silently drops.
+ *  2. A clinical query WITH a resolved agency returns zero results — a blank
+ *     screen for e.g. "chest pain dose" mid-call.
+ *
+ * Both are surfaced as Sentry alerts (operator signal) in addition to logs.
+ * Required before TestFlight beta per the resubmission AI-council (2026-06-01).
+ */
+import { captureMessage } from '../sentry';
+import { logger } from '../logger';
+
+export interface EmbeddingDegradedDetail {
+  reason: 'circuit_open' | 'embedding_error';
+  query: string;
+  agencyId?: number | null;
+  err?: unknown;
+}
+
+/**
+ * Fire when semantic search falls back to keyword-only because embeddings are
+ * unavailable. Operators must know clinical retrieval is degraded, not just see
+ * a buried logger.warn.
+ */
+export function alertEmbeddingDegraded(detail: EmbeddingDegradedDetail): void {
+  logger.error(
+    { reason: detail.reason, agencyId: detail.agencyId ?? null, err: detail.err },
+    '[Degradation] Semantic search degraded to keyword-only',
+  );
+  captureMessage(
+    `Clinical search degraded to keyword-only (${detail.reason}); semantic embeddings unavailable`,
+    'error',
+  );
+}
+
+export interface SilentEmptyDetail {
+  query: string;
+  agencyId: number | null;
+  agencyName?: string | null;
+  isClinical: boolean;
+}
+
+/**
+ * Fire when a clinical query that resolved to a real agency returns zero
+ * results — the "blank screen mid-call" case. Only fires when an agency is
+ * resolved AND the query is clinical, so unauthenticated / no-context probes
+ * that are empty by design do not alert.
+ */
+export function alertSilentEmptyResult(detail: SilentEmptyDetail): void {
+  if (detail.agencyId == null || !detail.isClinical) return;
+  logger.error(
+    { agencyId: detail.agencyId, agencyName: detail.agencyName ?? null, query: detail.query },
+    '[Degradation] Clinical query with resolved agency returned ZERO results',
+  );
+  captureMessage(
+    `Clinical search returned ZERO results for a resolved agency (agencyId=${detail.agencyId}) — possible silent retrieval failure`,
+    'error',
+  );
+}
diff --git a/server/_core/embeddings/search.ts b/server/_core/embeddings/search.ts
index 86be7d41..988bfaee 100644
--- a/server/_core/embeddings/search.ts
+++ b/server/_core/embeddings/search.ts
@@ -16,6 +16,7 @@ import type { SupabaseRpcResult, SearchResult } from './types';
 // Import and re-export keyword search utilities for backward compatibility
 import { extractProtocolNumber, keywordOnlySearch, mergeKeywordFallbackResults } from './keyword-search';
 import { logger } from '../logger';
+import { alertEmbeddingDegraded } from './degradation-alert';
 import { getCanonicalTitle } from './protocol-titles';
 export { extractProtocolNumber, keywordOnlySearch };
 
@@ -174,7 +175,8 @@ export async function semanticSearchProtocols(params: {
 
   // Check if Gemini is available - fallback to BM25 if not
   if (!isGeminiAvailable()) {
-    logger.warn('[Search] Gemini unavailable, using BM25 fallback');
+    // ALERT: embedding circuit breaker open — clinical search degraded to keyword-only.
+    alertEmbeddingDegraded({ reason: 'circuit_open', query, agencyId });
 
     // Use keyword fallback
     const fallbackResults = await keywordOnlySearch({
@@ -194,8 +196,9 @@ export async function semanticSearchProtocols(params: {
   try {
     queryEmbedding = await generateEmbedding(expandedQuery);
   } catch (error) {
-    // If embedding fails, fallback to BM25
-    logger.warn({ err: error }, '[Search] Embedding generation failed, using BM25 fallback');
+    // If embedding fails, fallback to BM25 — but ALERT: clinical search just
+    // silently degraded to keyword-only (council pre-beta requirement).
+    alertEmbeddingDegraded({ reason: 'embedding_error', query, agencyId, err: error });
     const fallbackResults = await keywordOnlySearch({
       query,
       agencyId,
diff --git a/server/routers/search/semantic.ts b/server/routers/search/semantic.ts
index 016c3348..1a7b8de5 100644
--- a/server/routers/search/semantic.ts
+++ b/server/routers/search/semantic.ts
@@ -24,6 +24,7 @@ import { validateSearchLimit, getUserTierFeatures } from "../../_core/tier-valid
 import { toStateCode } from "../../lib/state-codes";
 import { incrementAndCheckQueryLimit } from "../../db/users-usage";
 import { logger } from "../../_core/logger";
+import { alertSilentEmptyResult } from "../../_core/embeddings/degradation-alert";
 import { logQuery, createQueryLogEntry } from "../../_core/query-analytics";
 import { getDrugByName } from "../../db/drugs";
 import {
@@ -273,6 +274,18 @@ export const semanticRouter = router({
           latencyMs,
         };
 
+        // ALERT: a clinical query that resolved to a real agency came back empty
+        // — the "blank screen mid-call" case. Only fires when an agency resolved
+        // and the query is clinical (council pre-beta requirement 2026-06-01).
+        if (response.totalFound === 0) {
+          alertSilentEmptyResult({
+            query: input.query,
+            agencyId,
+            agencyName,
+            isClinical: isDrugRelated || isMedicationQuery,
+          });
+        }
+
         // Enrich medication queries with drug reference data
         if (isMedicationQuery && normalized.extractedMedications.length > 0) {
           try {
diff --git a/tests/embedding-degradation-alert.test.ts b/tests/embedding-degradation-alert.test.ts
new file mode 100644
index 00000000..27087ca9
--- /dev/null
+++ b/tests/embedding-degradation-alert.test.ts
@@ -0,0 +1,51 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import * as sentry from "../server/_core/sentry";
+import {
+  alertEmbeddingDegraded,
+  alertSilentEmptyResult,
+} from "../server/_core/embeddings/degradation-alert";
+
+/**
+ * Clinical-safety regression: silent-degradation detection must surface to the
+ * operator (Sentry), and must NOT false-alarm on benign empty results.
+ * Required before TestFlight beta per the resubmission AI-council (2026-06-01).
+ */
+describe("silent-degradation alerts", () => {
+  let spy: ReturnType<typeof vi.spyOn>;
+
+  beforeEach(() => {
+    spy = vi.spyOn(sentry, "captureMessage").mockImplementation(() => {});
+  });
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it("alerts at 'error' level when semantic search degrades to keyword-only (embedding error)", () => {
+    alertEmbeddingDegraded({ reason: "embedding_error", query: "chest pain dose", agencyId: 12 });
+    expect(spy).toHaveBeenCalledTimes(1);
+    expect(spy.mock.calls[0][1]).toBe("error");
+    expect(String(spy.mock.calls[0][0])).toContain("keyword-only");
+  });
+
+  it("alerts when the embedding circuit breaker is open", () => {
+    alertEmbeddingDegraded({ reason: "circuit_open", query: "stroke", agencyId: null });
+    expect(spy).toHaveBeenCalledTimes(1);
+    expect(String(spy.mock.calls[0][0])).toContain("circuit_open");
+  });
+
+  it("alerts when a clinical query with a resolved agency returns ZERO results", () => {
+    alertSilentEmptyResult({ query: "chest pain dose", agencyId: 7, isClinical: true });
+    expect(spy).toHaveBeenCalledTimes(1);
+    expect(String(spy.mock.calls[0][0])).toContain("agencyId=7");
+  });
+
+  it("does NOT alert on empty when no agency resolved (empty-by-design probe)", () => {
+    alertSilentEmptyResult({ query: "chest pain", agencyId: null, isClinical: true });
+    expect(spy).not.toHaveBeenCalled();
+  });
+
+  it("does NOT alert on empty for a non-clinical query", () => {
+    alertSilentEmptyResult({ query: "about page", agencyId: 7, isClinical: false });
+    expect(spy).not.toHaveBeenCalled();
+  });
+});