diff --git a/dev/ai-gateway-kustomization.yaml b/dev/ai-gateway-kustomization.yaml
index 68ca314..3d13303 100644
--- a/dev/ai-gateway-kustomization.yaml
+++ b/dev/ai-gateway-kustomization.yaml
@@ -18,6 +18,16 @@ spec:
     substitute:
       NAME: llm-dev
       NAMESPACE: llm
+      # 256k, against the 8k the other domains keep. Prompts here carry the
+      # conversation and the MCP tool definitions and already run to 30 KB;
+      # below this nginx spills the body to a temp file and
+      # kong.request.get_raw_body() returns nil, which is what left ai-proxy's
+      # log_payloads and log_statistics producing nothing at all.
+      #
+      # Affordable precisely because this gateway is low-traffic — the buffer is
+      # per connection carrying a body. Do not copy it to the domain gateways
+      # without doing that arithmetic for their volume.
+      CLIENT_BODY_BUFFER_SIZE: 256k
       HOSTNAME: llm-dev.sttlab.local
     substituteFrom:
       - kind: ConfigMap
diff --git a/kong/ai-proxy-advanced.yaml b/kong/ai-proxy-advanced.yaml
index c36a483..0d92067 100644
--- a/kong/ai-proxy-advanced.yaml
+++ b/kong/ai-proxy-advanced.yaml
@@ -5,6 +5,10 @@ metadata:
   namespace: ${NAMESPACE}
 plugin: ai-proxy-advanced
 config:
+  # The plugin's own ceiling on what it will introspect, distinct from nginx's
+  # client_body_buffer_size — both have to clear 30 KB prompts or the payload
+  # and usage logging stay empty. Raised together; neither alone is enough.
+  max_request_body_size: 262144
   targets:
     - route_type: llm/v1/chat
       auth: