diff --git a/docker-compose.yaml b/docker-compose.yaml
index 54c521d5..e1f5501d 100644
--- a/docker-compose.yaml
+++ b/docker-compose.yaml
@@ -34,6 +34,7 @@ services:
       EDC_WEB_REST_CORS_ENABLED: 'true'
       EDC_WEB_REST_CORS_HEADERS: 'origin,content-type,accept,authorization,x-api-key'
       EDC_WEB_REST_CORS_ORIGINS: '*'
+      EDC_AGENT_IDENTITY_KEY: 'client_id' # required for Mock IAM to work
     ports:
       - '11001:11001'
       - '11002:11002'
@@ -87,6 +88,7 @@ services:
       EDC_WEB_REST_CORS_ENABLED: 'true'
       EDC_WEB_REST_CORS_HEADERS: 'origin,content-type,accept,authorization,x-api-key'
       EDC_WEB_REST_CORS_ORIGINS: '*'
+      EDC_AGENT_IDENTITY_KEY: 'client_id' # required for Mock IAM to work
     ports:
       - '22001:11001'
       - '22002:11002'