diff --git a/packages/backend/src/server/api/endpoints/admin/emoji/add.ts b/packages/backend/src/server/api/endpoints/admin/emoji/add.ts
index ecfed084f..2f612fa7c 100644
--- a/packages/backend/src/server/api/endpoints/admin/emoji/add.ts
+++ b/packages/backend/src/server/api/endpoints/admin/emoji/add.ts
@@ -16,7 +16,7 @@ export const meta = {
 	errors: {
 		noSuchFile: {
 			message: 'No such file.',
-			code: 'MO_SUCH_FILE',
+			code: 'NO_SUCH_FILE',
 			id: 'fc46b5a4-6b92-4c33-ac66-b806659bb5cf',
 		},
 	},
diff --git a/packages/backend/src/server/api/endpoints/notes/reactions.ts b/packages/backend/src/server/api/endpoints/notes/reactions.ts
index d9388b47f..fc243c964 100644
--- a/packages/backend/src/server/api/endpoints/notes/reactions.ts
+++ b/packages/backend/src/server/api/endpoints/notes/reactions.ts
@@ -36,7 +36,11 @@ export const paramDef = {
 	type: 'object',
 	properties: {
 		noteId: { type: 'string', format: 'misskey:id' },
-		type: { type: 'string', nullable: true },
+		type: {
+			description: 'A Unicode emoji or custom emoji code. A custom emoji should look like `:name:` or `:name@example.com`.',
+			type: 'string',
+			nullable: true,
+		},
 		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
 		offset: { type: 'integer', default: 0 },
 		sinceId: { type: 'string', format: 'misskey:id' },
diff --git a/packages/backend/src/server/api/openapi/gen-spec.ts b/packages/backend/src/server/api/openapi/gen-spec.ts
index e205ab51e..48b57a03c 100644
--- a/packages/backend/src/server/api/openapi/gen-spec.ts
+++ b/packages/backend/src/server/api/openapi/gen-spec.ts
@@ -168,7 +168,7 @@ export function genOpenapiSpec() {
 				},
 				...(endpoint.meta.limit ? {
 					'429': {
-						description: 'To many requests',
+						description: 'Too many requests',
 						content: {
 							'application/json': {
 								schema: {