diff --git a/src/ai.ts b/src/ai.ts
index 701b97e..e436533 100644
--- a/src/ai.ts
+++ b/src/ai.ts
@@ -17,6 +17,7 @@ import Stream from '@/stream.js';
 import log from '@/utils/log.js';
 import { sleep } from './utils/sleep.js';
 import pkg from '../package.json' assert { type: 'json' };
+import { Note } from './misskey/note.js';
 
 type MentionHook = (msg: Message) => Promise<boolean | HandlerResult>;
 type ContextHook = (key: any, msg: Message, data?: any) => Promise<void | boolean | HandlerResult>;
@@ -361,7 +362,7 @@ export default class 藍 {
 	 */
 	@bindThis
 	public async post(param: any) {
-		const res = await this.api('notes/create', param);
+		const res = await this.api<{ createdNote: Note }>('notes/create', param);
 		return res.createdNote;
 	}
 
@@ -380,13 +381,13 @@ export default class 藍 {
 	 * APIを呼び出します
 	 */
 	@bindThis
-	public api(endpoint: string, param?: any) {
+	public api<ReturnType = unknown>(endpoint: string, param?: any) {
 		this.log(`API: ${endpoint}`);
 		return got.post(`${config.apiUrl}/${endpoint}`, {
 			json: Object.assign({
 				i: config.i
 			}, param)
-		}).json();
+		}).json<ReturnType>();
 	};
 
 	/**
diff --git a/src/index.ts b/src/index.ts
index 2f85f93..c1a41c4 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -34,6 +34,7 @@ import NotingModule from './modules/noting/index.js';
 import PollModule from './modules/poll/index.js';
 import ReminderModule from './modules/reminder/index.js';
 import CheckCustomEmojisModule from './modules/check-custom-emojis/index.js';
+import { User } from './misskey/user.js';
 
 console.log('   __    ____  _____  ___ ');
 console.log('  /__\\  (_  _)(  _  )/ __)');
@@ -61,7 +62,7 @@ promiseRetry(retry => {
 		json: {
 			i: config.i
 		}
-	}).json().catch(retry);
+	}).json<User>().catch(retry);
 }, {
 	retries: 3
 }).then(account => {
diff --git a/src/message.ts b/src/message.ts
index 104ca18..8f6971c 100644
--- a/src/message.ts
+++ b/src/message.ts
@@ -61,7 +61,7 @@ export default class Message {
 		this.friend = new Friend(ai, { user: this.user });
 
 		// メッセージなどに付いているユーザー情報は省略されている場合があるので完全なユーザー情報を持ってくる
-		this.ai.api('users/show', {
+		this.ai.api<User>('users/show', {
 			userId: this.userId
 		}).then(user => {
 			this.friend.updateUser(user);
diff --git a/src/modules/chart/index.ts b/src/modules/chart/index.ts
index 7605707..97d0f4c 100644
--- a/src/modules/chart/index.ts
+++ b/src/modules/chart/index.ts
@@ -6,6 +6,27 @@ import { renderChart } from './render-chart.js';
 import { items } from '@/vocabulary.js';
 import config from '@/config.js';
 
+type UserNotes = {
+	diffs: {
+		normal: number[],
+		reply: number[],
+		renote: number[]
+	}
+};
+
+type LocalRemotePair<T> = {
+	local: T,
+	remote: T
+};
+
+type UserFollowing = LocalRemotePair<{
+	followers: {
+		total: number[]
+	}
+}>;
+
+type Notes = LocalRemotePair<UserNotes>
+
 export default class extends Module {
 	public readonly name = 'chart';
 
@@ -48,7 +69,7 @@ export default class extends Module {
 		let chart;
 
 		if (type === 'userNotes') {
-			const data = await this.ai.api('charts/user/notes', {
+			const data = await this.ai.api<UserNotes>('charts/user/notes', {
 				span: 'day',
 				limit: 30,
 				userId: params.user.id
@@ -65,7 +86,7 @@ export default class extends Module {
 				}]
 			};
 		} else if (type === 'followers') {
-			const data = await this.ai.api('charts/user/following', {
+			const data = await this.ai.api<UserFollowing>('charts/user/following', {
 				span: 'day',
 				limit: 30,
 				userId: params.user.id
@@ -80,7 +101,7 @@ export default class extends Module {
 				}]
 			};
 		} else if (type === 'notes') {
-			const data = await this.ai.api('charts/notes', {
+			const data = await this.ai.api<Notes>('charts/notes', {
 				span: 'day',
 				limit: 30,
 			});
diff --git a/src/modules/keyword/index.ts b/src/modules/keyword/index.ts
index 31f7b0f..a1c7ad9 100644
--- a/src/modules/keyword/index.ts
+++ b/src/modules/keyword/index.ts
@@ -5,6 +5,12 @@ import config from '@/config.js';
 import serifs from '@/serifs.js';
 import { mecab } from './mecab.js';
 
+type LocalTimeline = {
+	userId: string;
+	text: string | null;
+	cw: string | null;
+}[];
+
 function kanaToHira(str: string) {
 	return str.replace(/[\u30a1-\u30f6]/g, match => {
 		const chr = match.charCodeAt(0) - 0x60;
@@ -35,7 +41,7 @@ export default class extends Module {
 
 	@bindThis
 	private async learn() {
-		const tl = await this.ai.api('notes/local-timeline', {
+		const tl = await this.ai.api<LocalTimeline>('notes/local-timeline', {
 			limit: 30
 		});
 
@@ -47,7 +53,8 @@ export default class extends Module {
 		let keywords: string[][] = [];
 
 		for (const note of interestedNotes) {
-			const tokens = await mecab(note.text, config.mecab, config.mecabDic);
+			// TODO: note.text に null チェックが必要?
+			const tokens = await mecab(note.text as string, config.mecab, config.mecabDic);
 			const keywordsInThisNote = tokens.filter(token => token[2] == '固有名詞' && token[8] != null);
 			keywords = keywords.concat(keywordsInThisNote);
 		}