diff --git a/packages/web/docs/src/content/gateway/other-features/security/demand-control.mdx b/packages/web/docs/src/content/gateway/other-features/security/demand-control.mdx
index 8e6f8a35df4..1f7b47bcfa4 100644
--- a/packages/web/docs/src/content/gateway/other-features/security/demand-control.mdx
+++ b/packages/web/docs/src/content/gateway/other-features/security/demand-control.mdx
@@ -101,6 +101,16 @@ query BookQuery {
 Even if you can set defaults and customize the cost calculation programmatically in the gateway, it
 can also be customized on the subgraph level by using `@cost` and `@listSize` directives.
 
+<Callout type="warning">
+
+Customization using directives is not available when using the Gateway in `proxy` mode without
+providing the `schema` option.
+
+This is because the schema is loaded via introspection when it is not provided, and introspection
+results do not include directives.
+
+</Callout>
+
 ### `@cost` directive on the subgraph level
 
 If you want to override the default cost calculations, you can use `@cost` directive on the subgraph
diff --git a/packages/web/docs/src/content/gateway/supergraph-proxy-source.mdx b/packages/web/docs/src/content/gateway/supergraph-proxy-source.mdx
index 8645eb4c1f1..e59d412a2eb 100644
--- a/packages/web/docs/src/content/gateway/supergraph-proxy-source.mdx
+++ b/packages/web/docs/src/content/gateway/supergraph-proxy-source.mdx
@@ -234,6 +234,16 @@ This allows you to add features such as [usage reporting](/docs/gateway/usage-re
 [persisted documents](/docs/gateway/persisted-documents) without modifying your existing GraphQL
 API.
 
+<Callout>
+
+When using the Gateway in `proxy` mode with introspection of the source schema, schema directives
+are not supported because they are not part of the introspection response.
+
+This means proxy mode with introspection is not compatible with directive driven cache, auth, demand
+and control, or any other feature relying on directives.
+
+</Callout>
+
 <Tabs items={['CLI', 'Configuration File']}>
 
 {/* CLI */}