diff --git a/docker-compose.yml b/docker-compose.yml
index ac5f2228..749b379e 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -135,6 +135,10 @@ services:
       REALTIME_LISTEN_ADDR: :38020
       REALTIME_RABBITMQ_URL: amqp://${RABBITMQ_USER:-stackup}:${RABBITMQ_PASSWORD:-stackup}@rabbitmq:38050/
       REALTIME_LOG_LEVEL: ${REALTIME_LOG_LEVEL:-info}
+      REALTIME_JWT_SECRET: ${JWT_SECRET:-}
+      REALTIME_CORE_BASE_URL: ${CORE_INTERNAL_BASE_URL:-http://backend:38010}
+      REALTIME_INTERNAL_API_KEY: ${CORE_INTERNAL_API_KEY:-local-development-internal-api-key}
+      REALTIME_WS_WRITE_TIMEOUT: ${REALTIME_WS_WRITE_TIMEOUT:-10s}
     depends_on:
       rabbitmq:
         condition: service_healthy
diff --git a/realtime/.env.example b/realtime/.env.example
index 64ca4f74..f39c2a3f 100644
--- a/realtime/.env.example
+++ b/realtime/.env.example
@@ -5,7 +5,11 @@ REALTIME_QUEUE_NAME=q.realtime.session.notify
 REALTIME_SSE_PING_INTERVAL=30s
 REALTIME_SSE_SLOW_CONSUMER_TIMEOUT=5s
 REALTIME_SSE_BUFFER_SIZE=16
-REALTIME_JWT_SECRET=change-me-in-prod
-REALTIME_CORE_BASE_URL=http://localhost:38080
-REALTIME_INTERNAL_API_KEY=change-me-internal-key
+# 아래 3개는 Core 와 공유하는 값. 반드시 Core 와 동일하게 맞출 것.
+#  - REALTIME_JWT_SECRET       == Core JWT_SECRET (stream 토큰 검증 키; 불일치 시 SSE/WS 인증 401)
+#  - REALTIME_INTERNAL_API_KEY == Core CORE_INTERNAL_API_KEY (WS 답변 프록시; AI 서버도 공유)
+#  - REALTIME_CORE_BASE_URL    == Core 내부 REST 주소 (compose 내부에서는 http://backend:38010)
+REALTIME_JWT_SECRET=local-development-jwt-secret-must-be-replaced
+REALTIME_CORE_BASE_URL=http://localhost:38010
+REALTIME_INTERNAL_API_KEY=local-development-internal-api-key
 REALTIME_WS_WRITE_TIMEOUT=10s
diff --git a/realtime/CLAUDE.md b/realtime/CLAUDE.md
index 416057b9..73ee1037 100644
--- a/realtime/CLAUDE.md
+++ b/realtime/CLAUDE.md
@@ -151,9 +151,9 @@ Heartbeat (proxy keepalive):
 | `REALTIME_SSE_PING_INTERVAL` | `30s` | SSE heartbeat 주기 |
 | `REALTIME_SSE_SLOW_CONSUMER_TIMEOUT` | `5s` | 구독자 send timeout |
 | `REALTIME_SSE_BUFFER_SIZE` | `16` | 구독자별 채널 버퍼 |
-| `REALTIME_JWT_SECRET` | `change-me-in-prod` | Stream 토큰 검증 키 소스 (Core `JWT_SECRET`과 동일값. 키 = `SHA-256(secret)`, HS256) |
-| `REALTIME_CORE_BASE_URL` | `http://localhost:38080` | Core 내부 REST base URL (WS 답변 프록시) |
-| `REALTIME_INTERNAL_API_KEY` | `change-me-internal-key` | Core 내부 API 호출용 `X-Internal-API-Key` |
+| `REALTIME_JWT_SECRET` | `local-development-jwt-secret-must-be-replaced` | **Core `JWT_SECRET`과 동일값 필수** (Stream 토큰 검증 키. 키=`SHA-256(secret)`, HS256). 불일치 시 SSE/WS 인증 401 |
+| `REALTIME_CORE_BASE_URL` | `http://localhost:38010` | Core 내부 REST base URL (WS 답변 프록시). compose 내부는 `http://backend:38010` |
+| `REALTIME_INTERNAL_API_KEY` | `local-development-internal-api-key` | **Core `CORE_INTERNAL_API_KEY`와 동일값 필수** (AI 서버도 공유). `X-Internal-API-Key` |
 | `REALTIME_WS_WRITE_TIMEOUT` | `10s` | WS write 타임아웃 |
 
 ---
diff --git a/realtime/internal/config/config.go b/realtime/internal/config/config.go
index ef32a9b8..643f77e6 100644
--- a/realtime/internal/config/config.go
+++ b/realtime/internal/config/config.go
@@ -11,9 +11,9 @@ type Config struct {
 	RabbitMQURL            string        `env:"REALTIME_RABBITMQ_URL" envDefault:"amqp://stackup:stackup@localhost:38050/"`
 	LogLevel               string        `env:"REALTIME_LOG_LEVEL" envDefault:"info"`
 	QueueName              string        `env:"REALTIME_QUEUE_NAME" envDefault:"q.realtime.session.notify"`
-	JWTSecret              string        `env:"REALTIME_JWT_SECRET" envDefault:"change-me-in-prod"`
-	CoreBaseURL            string        `env:"REALTIME_CORE_BASE_URL" envDefault:"http://localhost:38080"`
-	InternalApiKey         string        `env:"REALTIME_INTERNAL_API_KEY" envDefault:"change-me-internal-key"`
+	JWTSecret              string        `env:"REALTIME_JWT_SECRET" envDefault:"local-development-jwt-secret-must-be-replaced"`
+	CoreBaseURL            string        `env:"REALTIME_CORE_BASE_URL" envDefault:"http://localhost:38010"`
+	InternalApiKey         string        `env:"REALTIME_INTERNAL_API_KEY" envDefault:"local-development-internal-api-key"`
 	WSWriteTimeout         time.Duration `env:"REALTIME_WS_WRITE_TIMEOUT" envDefault:"10s"`
 	SSEPingInterval        time.Duration `env:"REALTIME_SSE_PING_INTERVAL" envDefault:"30s"`
 	SSESlowConsumerTimeout time.Duration `env:"REALTIME_SSE_SLOW_CONSUMER_TIMEOUT" envDefault:"5s"`