diff --git a/.jules/sentinel.md b/.jules/sentinel.md
index e795cb9dd..6df504907 100644
--- a/.jules/sentinel.md
+++ b/.jules/sentinel.md
@@ -32,3 +32,8 @@
 **Vulnerability:** The document hashing routine in `DefaultDocumentConversionService` processed file streams without enforcing any maximum size limit on the bytes read. An attacker could exploit this by uploading a maliciously large stream (or exploiting a compression bomb if unzipping), exhausting system memory, CPU, or disk space (DoS).
 **Learning:** Checking the declared file size (e.g., `file.getSize()`) in initial validation is not always sufficient if the input stream itself can be spoofed or dynamically expanded during reading. The actual bytes read must be verified against bounds continuously.
 **Prevention:** Always enforce a strict, configurable size limit (e.g., `ConversionProperties.maxUploadSizeBytes`) within the `while` loop that reads from untrusted input streams. Track `totalRead` and throw an exception immediately if the limit is exceeded.
+
+## 2026-08-29 - 환경변수를 통한 시크릿 주입 취약점 제거
+**Vulnerability:** `application-buyer-demo.yml`에서 런타임 시크릿(artifact-token HMAC secret, tenant-claims HMAC secret)이 스프링 환경변수 플레이스홀더(`${ENV_VAR:}`)를 통해 주입되고 있었습니다. 이는 환경변수가 런타임 소스로 사용되어 시크릿이 노출될 수 있는 보안 위험을 초래합니다.
+**Learning:** 런타임 설정이나 시크릿을 `os.getenv()`나 스프링 환경변수를 통해 직접 읽는 것은 안전하지 않습니다. 시크릿은 KV(Key-Value) 레지스트리나 DB 기반의 암호화된 저장소와 같이 안전한 소스에서 가져와야 하며, 환경변수는 KV로 데이터를 전송하는 용도로만 제한해야 합니다.
+**Prevention:** 환경변수 플레이스홀더를 제거하고 Spring Boot의 configtree 지원을 사용하여 시크릿을 런타임에 직접 로드하도록 마이그레이션해야 합니다. 스프링 `@Value` 애너테이션에서 빈 문자열의 디폴트 값을 제거하여 시작 시 실패하게 만들면(fail-fast), 보안 속성이 누락되었을 때의 취약점 방지에 도움을 줍니다.
diff --git a/src/main/java/com/clearfolio/viewer/artifact/ArtifactLinkService.java b/src/main/java/com/clearfolio/viewer/artifact/ArtifactLinkService.java
index 79a972e3d..bcee94fda 100644
--- a/src/main/java/com/clearfolio/viewer/artifact/ArtifactLinkService.java
+++ b/src/main/java/com/clearfolio/viewer/artifact/ArtifactLinkService.java
@@ -79,7 +79,7 @@ public class ArtifactLinkService {
     public ArtifactLinkService(
             ArtifactStore artifactStore,
             ArtifactLinkLedger artifactLinkLedger,
-            @Value("${clearfolio.artifact-token.secret:}") String configuredSecret) {
+            @Value("${clearfolio.artifact-token.secret}") String configuredSecret) {
         this(artifactStore, artifactLinkLedger, configuredSecret, Clock.systemUTC(), new SecureRandom());
     }
 
diff --git a/src/main/java/com/clearfolio/viewer/auth/TenantAccessService.java b/src/main/java/com/clearfolio/viewer/auth/TenantAccessService.java
index ab02e96a7..4531e0469 100644
--- a/src/main/java/com/clearfolio/viewer/auth/TenantAccessService.java
+++ b/src/main/java/com/clearfolio/viewer/auth/TenantAccessService.java
@@ -47,7 +47,7 @@ public TenantAccessService() {
      */
     @Autowired
     public TenantAccessService(
-            @Value("${clearfolio.tenant-claims.hmac-secret:}") String claimsHmacSecret,
+            @Value("${clearfolio.tenant-claims.hmac-secret}") String claimsHmacSecret,
             @Value("${clearfolio.tenant-claims.max-skew-seconds:300}") long maxSkewSeconds) {
         this(claimsHmacSecret, maxSkewSeconds, Clock.systemUTC());
     }
diff --git a/src/main/java/com/clearfolio/viewer/config/ProductionAuthReadinessConfig.java b/src/main/java/com/clearfolio/viewer/config/ProductionAuthReadinessConfig.java
index dfeb00a59..9752c40dd 100644
--- a/src/main/java/com/clearfolio/viewer/config/ProductionAuthReadinessConfig.java
+++ b/src/main/java/com/clearfolio/viewer/config/ProductionAuthReadinessConfig.java
@@ -18,7 +18,7 @@ public class ProductionAuthReadinessConfig {
      * @param tenantClaimsSecret shared gateway signing secret
      */
     public ProductionAuthReadinessConfig(
-            @Value("${clearfolio.tenant-claims.hmac-secret:}") String tenantClaimsSecret) {
+            @Value("${clearfolio.tenant-claims.hmac-secret}") String tenantClaimsSecret) {
         if (!StringUtils.hasText(tenantClaimsSecret)) {
             throw new IllegalStateException(
                     "production profile requires clearfolio.tenant-claims.hmac-secret"
diff --git a/src/main/resources/application-buyer-demo.yml b/src/main/resources/application-buyer-demo.yml
index 4e4df4091..56e5437ac 100644
--- a/src/main/resources/application-buyer-demo.yml
+++ b/src/main/resources/application-buyer-demo.yml
@@ -23,9 +23,7 @@ viewer:
 
 clearfolio:
   artifact-token:
-    secret: ${CLEARFOLIO_ARTIFACT_TOKEN_SECRET:}
   tenant-claims:
-    hmac-secret: ${CLEARFOLIO_TENANT_CLAIMS_HMAC_SECRET:}
     max-skew-seconds: ${CLEARFOLIO_TENANT_CLAIMS_MAX_SKEW_SECONDS:300}
   artifact-link-ledger:
     path: ${CLEARFOLIO_ARTIFACT_LINK_LEDGER_PATH:}
diff --git a/src/test/java/com/clearfolio/viewer/config/ProductionAuthReadinessConfigTest.java b/src/test/java/com/clearfolio/viewer/config/ProductionAuthReadinessConfigTest.java
index f00ba4c62..984f2c5ae 100644
--- a/src/test/java/com/clearfolio/viewer/config/ProductionAuthReadinessConfigTest.java
+++ b/src/test/java/com/clearfolio/viewer/config/ProductionAuthReadinessConfigTest.java
@@ -10,7 +10,7 @@ class ProductionAuthReadinessConfigTest {
     @Test
     void productionProfileFailsWithoutSignedTenantClaimsSecret() {
         productionRunner().run(context -> assertThat(context.getStartupFailure())
-                .hasRootCauseMessage("production profile requires clearfolio.tenant-claims.hmac-secret"));
+                .hasMessageContaining("Could not resolve placeholder"));
     }
 
     @Test