diff --git a/src/meta-schema.test.ts b/src/meta-schema.test.ts
index fa1a975..6bd8df2 100644
--- a/src/meta-schema.test.ts
+++ b/src/meta-schema.test.ts
@@ -10,6 +10,10 @@ import {
 } from './meta-schema';
 import { IntrospectionResponse } from './types';
 
+beforeEach(() => {
+  jest.spyOn(console, 'log').mockReturnValue(void 0);
+});
+
 describe('assumptions', () => {
   const FIXTURES: {
     name: string;
@@ -191,6 +195,53 @@ describe('loadSchemaFromFile', () => {
       Endpoints: {},
     });
   });
+
+  test('does not apply assumptions to introspection responses', () => {
+    const introspectionResponse: IntrospectionResponse = {
+      serviceVersion: 'mock-service-version',
+      schema: {
+        Endpoints: {
+          'GET /posts': {
+            Name: 'getPosts',
+            Response: {
+              type: 'object',
+              properties: {
+                something: { type: 'string' },
+              },
+            },
+          },
+        },
+      },
+    };
+
+    const filename = tmpNameSync();
+    writeFileSync(filename, dump(introspectionResponse), {
+      encoding: 'utf-8',
+    });
+
+    const result = loadSchemaFromFile(filename, {
+      objectPropertiesRequiredByDefault: true,
+      noAdditionalPropertiesOnObjects: true,
+    });
+
+    expect(result).toStrictEqual({
+      Endpoints: {
+        'GET /posts': {
+          Name: 'getPosts',
+          Response: {
+            type: 'object',
+            properties: {
+              something: { type: 'string' },
+            },
+          },
+        },
+      },
+    });
+
+    expect(console.log).toHaveBeenCalledWith(
+      'Detected one-schema introspection response. Skipping applying schema assumptions.',
+    );
+  });
 });
 
 describe('validateSchema', () => {
diff --git a/src/meta-schema.ts b/src/meta-schema.ts
index c50cac4..f9712f4 100644
--- a/src/meta-schema.ts
+++ b/src/meta-schema.ts
@@ -193,12 +193,23 @@ export const loadSchemaFromFile = (
 ): OneSchemaDefinition => {
   let spec: any = load(readFileSync(filename, { encoding: 'utf-8' }));
 
-  // Check if this in an introspection result. If so, grab the schema.
-  if (typeof spec === 'object' && 'schema' in spec) {
+  let applyAssumptions = true;
+
+  // Check if this in an introspection result. If so, grab the schema,
+  // and skip applying assumptions. Schemas served directly from services
+  // should always be correct + complete.
+  const isIntrospectionResult = typeof spec === 'object' && 'schema' in spec;
+  if (isIntrospectionResult) {
     spec = spec.schema;
+    applyAssumptions = false;
+    console.log(
+      'Detected one-schema introspection response. Skipping applying schema assumptions.',
+    );
   }
 
   validateSchema(spec as OneSchemaDefinition);
 
-  return withAssumptions(spec as OneSchemaDefinition, assumptions);
+  return applyAssumptions
+    ? withAssumptions(spec as OneSchemaDefinition, assumptions)
+    : spec;
 };