diff --git a/dataplane-template/gatewayconfiguration.yaml b/dataplane-template/gatewayconfiguration.yaml
index 7bd617e..7810acb 100644
--- a/dataplane-template/gatewayconfiguration.yaml
+++ b/dataplane-template/gatewayconfiguration.yaml
@@ -35,6 +35,18 @@ spec:
                   value: "256k"
                 - name: KONG_NGINX_HTTP_LARGE_CLIENT_HEADER_BUFFERS
                   value: "4 32k"
+                # How much of a request body nginx keeps in memory. Past it the body
+                # goes to a temp file, and kong.request.get_raw_body() returns nil for
+                # a body on disk — so any plugin that reads the body silently stops
+                # working. That is what kept ai-proxy's log_payloads and log_statistics
+                # empty on the AI gateway, whose prompts run to 30 KB against this 8k
+                # default.
+                #
+                # Per domain, not global: the buffer is allocated per connection carrying
+                # a body, so a value that is free on a gateway seeing 18 requests a day
+                # is not free on one serving real traffic.
+                - name: KONG_NGINX_HTTP_CLIENT_BODY_BUFFER_SIZE
+                  value: "${CLIENT_BODY_BUFFER_SIZE}"
   konnect:
     authRef:
       name: ${NAME}
diff --git a/kong-platform/dataplane-template-defaults.yaml b/kong-platform/dataplane-template-defaults.yaml
index e9cfbaf..e94994f 100644
--- a/kong-platform/dataplane-template-defaults.yaml
+++ b/kong-platform/dataplane-template-defaults.yaml
@@ -18,6 +18,9 @@ data:
   CORS_ORIGINS: https://*.sttlab.local
   RATE_LIMIT_MINUTE: "300"
   REQUEST_MAX_BODY_SIZE: "10" # MB
+  # nginx default. Domains that need to introspect larger bodies raise it
+  # in their own Kustomization; see the AI gateway.
+  CLIENT_BODY_BUFFER_SIZE: 8k
   # Tempo (OTLP-native), ns observability, cluster-wide — shared by every
   # domain, not domain-specific. Replaced Jaeger on 2026-08-25: Tempo is the
   # trace backend of the infra-observability stack, so its span metrics feed
diff --git a/kong-platform/domain-defaults/dataplane-template-defaults.yaml b/kong-platform/domain-defaults/dataplane-template-defaults.yaml
index 79be5f6..1979ff2 100644
--- a/kong-platform/domain-defaults/dataplane-template-defaults.yaml
+++ b/kong-platform/domain-defaults/dataplane-template-defaults.yaml
@@ -21,6 +21,9 @@ data:
   CORS_ORIGINS: https://*.sttlab.local
   RATE_LIMIT_MINUTE: "300"
   REQUEST_MAX_BODY_SIZE: "10" # MB
+  # nginx default. Domains that need to introspect larger bodies raise it
+  # in their own Kustomization; see the AI gateway.
+  CLIENT_BODY_BUFFER_SIZE: 8k
   # Tempo (OTLP-native), ns observability, cluster-wide — shared by every
   # domain, not domain-specific. Replaced Jaeger on 2026-08-25: Tempo is the
   # trace backend of the infra-observability stack, so its span metrics feed