From 6c737cb68e910ee450ea86e70a2752e69570ccbf Mon Sep 17 00:00:00 2001
From: Dan Lynch <pyramation@gmail.com>
Date: Tue, 8 Sep 2026 21:32:11 +0000
Subject: [PATCH] fix(graphql-server): exempt schema introspection from the
 depth and cost gate

The standard introspection document nests __schema > types > fields > args >
type > ofType x7 (depth 13), which the default max_query_depth of 12 rejects,
so every codegen run against a protected endpoint failed with QUERY_TOO_DEEP.
Introspection is governed by enable_introspection alone; its selections carry
no connections and are not walked.
---
 .../__tests__/document-gate.test.ts           | 22 +++++++++++++++++++
 .../server/src/protection/document-gate.ts    |  8 +++++++
 2 files changed, 30 insertions(+)

diff --git a/graphql/server/src/protection/__tests__/document-gate.test.ts b/graphql/server/src/protection/__tests__/document-gate.test.ts
index 40f686b7c..3d321387b 100644
--- a/graphql/server/src/protection/__tests__/document-gate.test.ts
+++ b/graphql/server/src/protection/__tests__/document-gate.test.ts
@@ -181,6 +181,28 @@ describe('introspection', () => {
     expect(() => enforce('{ __schema { queryType { name } } }')).not.toThrow();
   });
 
+  it('does not charge the standard introspection document against the depth budget', () => {
+    const source = `
+      { __schema { types { fields { args { type { ...TypeRef } } } } } }
+      fragment TypeRef on __Type {
+        kind name
+        ofType { kind name ofType { kind name ofType { kind name ofType { kind name
+          ofType { kind name ofType { kind name ofType { kind name } } } } } } }
+      }
+    `;
+    expect(enforce(source, { maxQueryDepth: 3 })).toEqual({ depth: 1, cost: 0 });
+  });
+
+  it('still measures the rest of an operation that also introspects', () => {
+    expect(
+      codeOf(() =>
+        enforce('{ __schema { queryType { name } } user(id: "1") { manager { manager { name } } } }', {
+          maxQueryDepth: 3
+        })
+      )
+    ).toBe('QUERY_TOO_DEEP');
+  });
+
   it('never blocks __typename, which is not introspection of the schema', () => {
     expect(() =>
       enforce('{ user(id: "1") { __typename name } }', { enableIntrospection: false })
diff --git a/graphql/server/src/protection/document-gate.ts b/graphql/server/src/protection/document-gate.ts
index aaca15d4e..9ecbd96ac 100644
--- a/graphql/server/src/protection/document-gate.ts
+++ b/graphql/server/src/protection/document-gate.ts
@@ -16,6 +16,13 @@
  * The walk is manual rather than `visitWithTypeInfo` because fragment spreads
  * have to be followed (a document can hide its depth entirely inside
  * fragments) and the visitor does not follow them.
+ *
+ * Schema introspection (`__schema` / `__type`) is governed only by
+ * `enableIntrospection`. Its selections are not walked: the introspection types
+ * carry no connections, so there is nothing to cost, and the standard
+ * introspection document nests a fixed `ofType` chain deeper than a sensible
+ * tenant depth budget, so charging depth would make the budget decide whether
+ * clients can introspect at all — a decision the dedicated switch already owns.
  */
 
 import type { ConstructiveError } from '@constructive-io/errors';
@@ -119,6 +126,7 @@ function walkSelectionSet(
         if (!walk.protection.enableIntrospection) {
           reject(errors.INTROSPECTION_DISABLED());
         }
+        continue;
       }
 
       const field =