diff --git a/.changeset/plenty-cooks-mix.md b/.changeset/plenty-cooks-mix.md
new file mode 100644
index 00000000..ce74fcc9
--- /dev/null
+++ b/.changeset/plenty-cooks-mix.md
@@ -0,0 +1,5 @@
+---
+'@interledger/open-payments': minor
+---
+
+Added GNAP error models to auth server responses.
diff --git a/openapi/auth-server.yaml b/openapi/auth-server.yaml
index eb30e628..5a908924 100644
--- a/openapi/auth-server.yaml
+++ b/openapi/auth-server.yaml
@@ -74,10 +74,24 @@ paths:
                       uri: 'https://auth.rafiki.money/continue/4CF492MLVMSW9MKMXKHQ'
         '400':
           description: Bad Request
+          content:
+            application/json:
+              schema:
+                oneOf:
+                  - $ref: '#/components/schemas/error-invalid-request'
+                  - $ref: '#/components/schemas/error-invalid-client'
         '401':
           description: Unauthorized
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/error-invalid-client'
         '500':
           description: Internal Server Error
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/error-request-denied'
       requestBody:
         content:
           application/json:
@@ -198,10 +212,29 @@ paths:
                       wait: 30
         '400':
           description: Bad Request
+          content:
+            application/json:
+              schema:
+                oneOf:
+                  - $ref: '#/components/schemas/error-too-fast'
+                  - $ref: '#/components/schemas/error-invalid-client'
         '401':
           description: Unauthorized
+          content:
+            application/json:
+              schema:
+                oneOf:
+                  - $ref: '#/components/schemas/error-invalid-client'
+                  - $ref: '#/components/schemas/error-invalid-continuation'
+                  - $ref: '#/components/schemas/error-request-denied'
         '404':
           description: Not Found
+          content:
+            application/json:
+              schema:
+                oneOf:
+                  - $ref: '#/components/schemas/error-invalid-continuation'
+                  - $ref: '#/components/schemas/error-invalid-request'
       requestBody:
         content:
           application/json:
@@ -226,12 +259,21 @@ paths:
       responses:
         '204':
           description: No Content
-        '400':
-          description: Bad Request
         '401':
           description: Unauthorized
+          content:
+            application/json:
+              schema:
+                oneOf:
+                  - $ref: '#/components/schemas/error-invalid-client'
+                  - $ref: '#/components/schemas/error-invalid-continuation'
+                  - $ref: '#/components/schemas/error-invalid-request'
         '404':
           description: Not Found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/error-invalid-request'
       description: Cancel a grant request or delete a grant client side.
       tags:
         - grant
@@ -279,10 +321,28 @@ paths:
                               assetScale: 2
         '400':
           description: Bad Request
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/error-invalid-rotation'
         '401':
           description: Unauthorized
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/error-invalid-client'
         '404':
           description: Not Found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/error-invalid-rotation'
+        '500':
+          description: Internal Server Error
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/error-request-denied'
       description: Management endpoint to rotate access token.
       tags:
         - token
@@ -293,10 +353,18 @@ paths:
       responses:
         '204':
           description: No Content
-        '400':
-          description: Bad Request
         '401':
           description: Unauthorized
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/error-invalid-client'
+        '500':
+          description: Internal Server Error
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/error-request-denied'
       tags:
         - token
 components:
@@ -532,6 +600,78 @@ components:
             - debitAmount
         - required:
             - receiveAmount
+    error-invalid-client:
+      type: object
+      properties:
+        error:
+          type: object
+          properties:
+            description:
+              type: string
+            code:
+              type: string
+              enum:
+                - invalid_client
+    error-invalid-request:
+      type: object
+      properties:
+        error:
+          type: object
+          properties:
+            description:
+              type: string
+            code:
+              type: string
+              enum:
+                - invalid_request
+    error-request-denied:
+      type: object
+      properties:
+        error:
+          type: object
+          properties:
+            description:
+              type: string
+            code:
+              type: string
+              enum:
+                - request_denied
+    error-too-fast:
+      type: object
+      properties:
+        error:
+          type: object
+          properties:
+            description:
+              type: string
+            code:
+              type: string
+              enum:
+                - too_fast
+    error-invalid-continuation:
+      type: object
+      properties:
+        error:
+          type: object
+          properties:
+            description:
+              type: string
+            code:
+              type: string
+              enum:
+                - invalid_continuation
+    error-invalid-rotation:
+      type: object
+      properties:
+        error:
+          type: object
+          properties:
+            description:
+              type: string
+            code:
+              type: string
+              enum:
+                - invalid_rotation
   securitySchemes:
     GNAP:
       name: Authorization
diff --git a/packages/open-payments/src/openapi/generated/auth-server-types.ts b/packages/open-payments/src/openapi/generated/auth-server-types.ts
index 00c0cf44..64d7b757 100644
--- a/packages/open-payments/src/openapi/generated/auth-server-types.ts
+++ b/packages/open-payments/src/openapi/generated/auth-server-types.ts
@@ -172,6 +172,42 @@ export interface components {
       receiveAmount?: external["schemas.yaml"]["components"]["schemas"]["amount"];
       interval?: components["schemas"]["interval"];
     };
+    "error-invalid-client": {
+      error?: {
+        description?: string;
+        code?: "invalid_client";
+      };
+    };
+    "error-invalid-request": {
+      error?: {
+        description?: string;
+        code?: "invalid_request";
+      };
+    };
+    "error-request-denied": {
+      error?: {
+        description?: string;
+        code?: "request_denied";
+      };
+    };
+    "error-too-fast": {
+      error?: {
+        description?: string;
+        code?: "too_fast";
+      };
+    };
+    "error-invalid-continuation": {
+      error?: {
+        description?: string;
+        code?: "invalid_continuation";
+      };
+    };
+    "error-invalid-rotation": {
+      error?: {
+        description?: string;
+        code?: "invalid_rotation";
+      };
+    };
   };
 }
 
@@ -195,11 +231,25 @@ export interface operations {
         };
       };
       /** Bad Request */
-      400: unknown;
+      400: {
+        content: {
+          "application/json":
+            | components["schemas"]["error-invalid-request"]
+            | components["schemas"]["error-invalid-client"];
+        };
+      };
       /** Unauthorized */
-      401: unknown;
+      401: {
+        content: {
+          "application/json": components["schemas"]["error-invalid-client"];
+        };
+      };
       /** Internal Server Error */
-      500: unknown;
+      500: {
+        content: {
+          "application/json": components["schemas"]["error-request-denied"];
+        };
+      };
     };
     requestBody: {
       content: {
@@ -231,11 +281,30 @@ export interface operations {
         };
       };
       /** Bad Request */
-      400: unknown;
+      400: {
+        content: {
+          "application/json":
+            | components["schemas"]["error-too-fast"]
+            | components["schemas"]["error-invalid-client"];
+        };
+      };
       /** Unauthorized */
-      401: unknown;
+      401: {
+        content: {
+          "application/json":
+            | components["schemas"]["error-invalid-client"]
+            | components["schemas"]["error-invalid-continuation"]
+            | components["schemas"]["error-request-denied"];
+        };
+      };
       /** Not Found */
-      404: unknown;
+      404: {
+        content: {
+          "application/json":
+            | components["schemas"]["error-invalid-continuation"]
+            | components["schemas"]["error-invalid-request"];
+        };
+      };
     };
     requestBody: {
       content: {
@@ -259,12 +328,21 @@ export interface operations {
     responses: {
       /** No Content */
       204: never;
-      /** Bad Request */
-      400: unknown;
       /** Unauthorized */
-      401: unknown;
+      401: {
+        content: {
+          "application/json":
+            | components["schemas"]["error-invalid-client"]
+            | components["schemas"]["error-invalid-continuation"]
+            | components["schemas"]["error-invalid-request"];
+        };
+      };
       /** Not Found */
-      404: unknown;
+      404: {
+        content: {
+          "application/json": components["schemas"]["error-invalid-request"];
+        };
+      };
     };
   };
   /** Management endpoint to rotate access token. */
@@ -284,11 +362,29 @@ export interface operations {
         };
       };
       /** Bad Request */
-      400: unknown;
+      400: {
+        content: {
+          "application/json": components["schemas"]["error-invalid-rotation"];
+        };
+      };
       /** Unauthorized */
-      401: unknown;
+      401: {
+        content: {
+          "application/json": components["schemas"]["error-invalid-client"];
+        };
+      };
       /** Not Found */
-      404: unknown;
+      404: {
+        content: {
+          "application/json": components["schemas"]["error-invalid-rotation"];
+        };
+      };
+      /** Internal Server Error */
+      500: {
+        content: {
+          "application/json": components["schemas"]["error-request-denied"];
+        };
+      };
     };
   };
   /** Management endpoint to revoke access token. */
@@ -301,10 +397,18 @@ export interface operations {
     responses: {
       /** No Content */
       204: never;
-      /** Bad Request */
-      400: unknown;
       /** Unauthorized */
-      401: unknown;
+      401: {
+        content: {
+          "application/json": components["schemas"]["error-invalid-client"];
+        };
+      };
+      /** Internal Server Error */
+      500: {
+        content: {
+          "application/json": components["schemas"]["error-request-denied"];
+        };
+      };
     };
   };
 }