diff --git a/internal/handlers/llm_services.go b/internal/handlers/llm_services.go
index 49060f7..ffaae79 100644
--- a/internal/handlers/llm_services.go
+++ b/internal/handlers/llm_services.go
@@ -303,7 +303,7 @@ func shareDefinitionFunc(ctx context.Context, input *models.ShareDefinitionReque
 		return nil, huma.Error500InternalServerError(fmt.Sprintf("unable to retrieve definition: %v", err))
 	}
 	if definition.Owner != ctx.Value(auth.AuthUserKey).(string) {
-		return nil, huma.Error401Unauthorized(fmt.Sprintf("Not authorized to share definition %s/%s", input.UserHandle, input.DefinitionHandle))
+		return nil, huma.Error403Forbidden(fmt.Sprintf("not authorized to share definition %s/%s", input.UserHandle, input.DefinitionHandle))
 	}
 
 	// Check if target user exists
@@ -353,7 +353,7 @@ func unshareDefinitionFunc(ctx context.Context, input *models.UnshareDefinitionR
 		return nil, huma.Error500InternalServerError(fmt.Sprintf("unable to retrieve definition: %v", err))
 	}
 	if definition.Owner != ctx.Value(auth.AuthUserKey).(string) {
-		return nil, huma.Error401Unauthorized(fmt.Sprintf("Not authorized to share definition %s/%s", input.UserHandle, input.DefinitionHandle))
+		return nil, huma.Error403Forbidden(fmt.Sprintf("not authorized to share definition %s/%s", input.UserHandle, input.DefinitionHandle))
 	}
 	fmt.Printf("Definition retrieved: %s/%s (id %d)\n", definition.Owner, definition.DefinitionHandle, definition.DefinitionID)
 	fmt.Printf("Attempting to unshare with %s\n", input.UnshareWithHandle)
@@ -574,7 +574,7 @@ func postInstanceFromDefinitionFunc(ctx context.Context, input *models.PostInsta
 				hasAccess = true
 			}
 			if !hasAccess {
-				return huma.Error401Unauthorized(fmt.Sprintf("user does not have access to definition %s/%s", input.Body.DefinitionOwner, input.Body.DefinitionHandle))
+				return huma.Error403Forbidden(fmt.Sprintf("user does not have access to definition %s/%s", input.Body.DefinitionOwner, input.Body.DefinitionHandle))
 			}
 		}
 
@@ -849,7 +849,7 @@ func shareInstanceFunc(ctx context.Context, input *models.ShareInstanceRequest)
 	}
 	// Check if instance belongs to current user (only owner can share)
 	if instance.Owner != ctx.Value(auth.AuthUserKey).(string) {
-		return nil, huma.Error401Unauthorized(fmt.Sprintf("Not authorized to share instance %s/%s", input.UserHandle, input.InstanceHandle))
+		return nil, huma.Error403Forbidden(fmt.Sprintf("not authorized to share instance %s/%s", input.UserHandle, input.InstanceHandle))
 	}
 	// Check if target user exists
 	_, err = getUserFunc(ctx, &models.GetUserRequest{UserHandle: input.Body.ShareWithHandle})
diff --git a/internal/handlers/llm_services_sharing_test.go b/internal/handlers/llm_services_sharing_test.go
index 99baa4e..6f47b01 100644
--- a/internal/handlers/llm_services_sharing_test.go
+++ b/internal/handlers/llm_services_sharing_test.go
@@ -265,8 +265,8 @@ func TestDefinitionSharingFunc(t *testing.T) {
 			requestPath:  "/v1/llm-instances/bob/from-definition",
 			bodyJSON:     `{"user_handle": "bob", "instance_handle": "bob-instance1", "definition_owner": "alice", "definition_handle": "openai-large", "endpoint": "https://api.openai.com/v1/embeddings", "description": "Bob's instance based on Alice's definition"}`,
 			VDBKey:       bobAPIKey,
-			expectBody:   "{\n  \"$schema\": \"http://localhost:8080/schemas/ErrorModel.json\",\n  \"title\": \"Unauthorized\",\n  \"status\": 401,\n  \"detail\": \"user does not have access to definition alice/openai-large\"\n}\n",
-			expectStatus: http.StatusUnauthorized,
+			expectBody:   "{\n  \"$schema\": \"http://localhost:8080/schemas/ErrorModel.json\",\n  \"title\": \"Forbidden\",\n  \"status\": 403,\n  \"detail\": \"user does not have access to definition alice/openai-large\"\n}\n",
+			expectStatus: http.StatusForbidden,
 		},
 		{
 			name:         "Create an instance based on a nonexistent definition - should fail",
diff --git a/internal/handlers/projects.go b/internal/handlers/projects.go
index 822092f..eb9facf 100644
--- a/internal/handlers/projects.go
+++ b/internal/handlers/projects.go
@@ -437,7 +437,7 @@ func shareProjectFunc(ctx context.Context, input *models.ShareProjectRequest) (*
 	}
 	// Check if project belongs to current user (only owner can share)
 	if project.Owner != ctx.Value(auth.AuthUserKey).(string) {
-		return nil, huma.Error401Unauthorized(fmt.Sprintf("not authorized to share project %s/%s", input.UserHandle, input.ProjectHandle))
+		return nil, huma.Error403Forbidden(fmt.Sprintf("not authorized to share project %s/%s", input.UserHandle, input.ProjectHandle))
 	}
 	// Check if target user exists
 	_, err = getUserFunc(ctx, &models.GetUserRequest{UserHandle: input.Body.ShareWithHandle})