diff --git a/src/utilities/__tests__/findSchemaChanges-test.ts b/src/utilities/__tests__/findSchemaChanges-test.ts
index 8c21781554..4aa351707b 100644
--- a/src/utilities/__tests__/findSchemaChanges-test.ts
+++ b/src/utilities/__tests__/findSchemaChanges-test.ts
@@ -2,7 +2,12 @@ import { expect } from 'chai';
 import { describe, it } from 'mocha';
 
 import { buildSchema } from '../buildASTSchema.js';
-import { findSchemaChanges, SafeChangeType } from '../findSchemaChanges.js';
+import {
+  BreakingChangeType,
+  DangerousChangeType,
+  findSchemaChanges,
+  SafeChangeType,
+} from '../findSchemaChanges.js';
 
 describe('findSchemaChanges', () => {
   it('should detect if a type was added', () => {
@@ -171,6 +176,147 @@ describe('findSchemaChanges', () => {
     ]);
   });
 
+  it('should detect if a changes argument safely', () => {
+    const oldSchema = buildSchema(`
+      directive @Foo(foo: String!) on FIELD_DEFINITION
+
+      type Query {
+        foo: String
+      }
+    `);
+
+    const newSchema = buildSchema(`
+      directive @Foo(foo: String) on FIELD_DEFINITION
+
+      type Query {
+        foo: String
+      }
+    `);
+    expect(findSchemaChanges(oldSchema, newSchema)).to.deep.equal([
+      {
+        description:
+          'Argument @Foo(foo:) has changed type from String! to String.',
+        type: SafeChangeType.ARG_CHANGED_KIND_SAFE,
+      },
+    ]);
+  });
+
+  it('should detect if a default value is added to an argument', () => {
+    const oldSchema = buildSchema(`
+      directive @Foo(foo: String) on FIELD_DEFINITION
+
+      type Query {
+        foo: String
+      }
+    `);
+
+    const newSchema = buildSchema(`
+      directive @Foo(foo: String = "Foo") on FIELD_DEFINITION
+
+      type Query {
+        foo: String
+      }
+    `);
+    expect(findSchemaChanges(oldSchema, newSchema)).to.deep.equal([
+      {
+        description: '@Foo(foo:) added a defaultValue "Foo".',
+        type: SafeChangeType.ARG_DEFAULT_VALUE_ADDED,
+      },
+    ]);
+  });
+
+  it('should detect if a default value is removed from an argument', () => {
+    const newSchema = buildSchema(`
+      directive @Foo(foo: String) on FIELD_DEFINITION
+
+      type Query {
+        foo: String
+      }
+    `);
+
+    const oldSchema = buildSchema(`
+      directive @Foo(foo: String = "Foo") on FIELD_DEFINITION
+
+      type Query {
+        foo: String
+      }
+    `);
+    expect(findSchemaChanges(oldSchema, newSchema)).to.deep.equal([
+      {
+        description: '@Foo(foo:) defaultValue was removed.',
+        type: DangerousChangeType.ARG_DEFAULT_VALUE_CHANGE,
+      },
+    ]);
+  });
+
+  it('should detect if a default value is changed in an argument', () => {
+    const oldSchema = buildSchema(`
+      directive @Foo(foo: String = "Bar") on FIELD_DEFINITION
+
+      type Query {
+        foo: String
+      }
+    `);
+
+    const newSchema = buildSchema(`
+      directive @Foo(foo: String = "Foo") on FIELD_DEFINITION
+
+      type Query {
+        foo: String
+      }
+    `);
+    expect(findSchemaChanges(oldSchema, newSchema)).to.deep.equal([
+      {
+        description: '@Foo(foo:) has changed defaultValue from "Bar" to "Foo".',
+        type: DangerousChangeType.ARG_DEFAULT_VALUE_CHANGE,
+      },
+    ]);
+  });
+
+  it('should detect if a directive argument does a breaking change', () => {
+    const oldSchema = buildSchema(`
+      directive @Foo(foo: String) on FIELD_DEFINITION
+
+      type Query {
+        foo: String
+      }
+    `);
+
+    const newSchema = buildSchema(`
+      directive @Foo(foo: String!) on FIELD_DEFINITION
+
+      type Query {
+        foo: String
+      }
+    `);
+    expect(findSchemaChanges(oldSchema, newSchema)).to.deep.equal([
+      {
+        description:
+          'Argument @Foo(foo:) has changed type from String to String!.',
+        type: BreakingChangeType.ARG_CHANGED_KIND,
+      },
+    ]);
+  });
+
+  it('should not detect if a directive argument default value does not change', () => {
+    const oldSchema = buildSchema(`
+      directive @Foo(foo: String = "FOO") on FIELD_DEFINITION
+
+      type Query {
+        foo: String
+      }
+    `);
+
+    const newSchema = buildSchema(`
+      directive @Foo(foo: String = "FOO") on FIELD_DEFINITION
+
+      type Query {
+        foo: String
+      }
+    `);
+    expect(findSchemaChanges(oldSchema, newSchema)).to.deep.equal([]);
+  });
+
   it('should detect if a directive changes description', () => {
     const oldSchema = buildSchema(`
       directive @Foo on FIELD_DEFINITION
diff --git a/src/utilities/findSchemaChanges.ts b/src/utilities/findSchemaChanges.ts
index b9c49aa59e..4cffd5aad6 100644
--- a/src/utilities/findSchemaChanges.ts
+++ b/src/utilities/findSchemaChanges.ts
@@ -196,6 +196,56 @@ function findDirectiveChanges(
     }
 
     for (const [oldArg, newArg] of argsDiff.persisted) {
+      const isSafe = isChangeSafeForInputObjectFieldOrFieldArg(
+        oldArg.type,
+        newArg.type,
+      );
+
+      if (!isSafe) {
+        schemaChanges.push({
+          type: BreakingChangeType.ARG_CHANGED_KIND,
+          description:
+            `Argument @${oldDirective.name}(${oldArg.name}:) has changed type from ` +
+            `${String(oldArg.type)} to ${String(newArg.type)}.`,
+        });
+      } else if (oldArg.defaultValue !== undefined) {
+        if (newArg.defaultValue === undefined) {
+          schemaChanges.push({
+            type: DangerousChangeType.ARG_DEFAULT_VALUE_CHANGE,
+            description: `@${oldDirective.name}(${oldArg.name}:) defaultValue was removed.`,
+          });
+        } else {
+          // Since we looking only for client's observable changes we should
+          // compare default values in the same representation as they are
+          // represented inside introspection.
+          const oldValueStr = stringifyValue(oldArg.defaultValue, oldArg.type);
+          const newValueStr = stringifyValue(newArg.defaultValue, newArg.type);
+
+          if (oldValueStr !== newValueStr) {
+            schemaChanges.push({
+              type: DangerousChangeType.ARG_DEFAULT_VALUE_CHANGE,
+              description: `@${oldDirective.name}(${oldArg.name}:) has changed defaultValue from ${oldValueStr} to ${newValueStr}.`,
+            });
+          }
+        }
+      } else if (
+        newArg.defaultValue !== undefined &&
+        oldArg.defaultValue === undefined
+      ) {
+        const newValueStr = stringifyValue(newArg.defaultValue, newArg.type);
+        schemaChanges.push({
+          type: SafeChangeType.ARG_DEFAULT_VALUE_ADDED,
+          description: `@${oldDirective.name}(${oldArg.name}:) added a defaultValue ${newValueStr}.`,
+        });
+      } else if (oldArg.type.toString() !== newArg.type.toString()) {
+        schemaChanges.push({
+          type: SafeChangeType.ARG_CHANGED_KIND_SAFE,
+          description:
+            `Argument @${oldDirective.name}(${oldArg.name}:) has changed type from ` +
+            `${String(oldArg.type)} to ${String(newArg.type)}.`,
+        });
+      }
+
       if (oldArg.description !== newArg.description) {
         schemaChanges.push({
           type: SafeChangeType.DESCRIPTION_CHANGED,