diff --git a/.vscode/settings.json b/.vscode/settings.json
index 01a32aa..4383804 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -21,5 +21,9 @@
   "[json]": {
     "editor.defaultFormatter": "esbenp.prettier-vscode"
   },
-  "cSpell.words": ["shadcn", "tabler"]
+  "[markdown]": {
+    "editor.tabSize": 4,
+    "editor.defaultFormatter": "DavidAnson.vscode-markdownlint"
+  },
+  "cSpell.words": ["Modbus", "shadcn", "tabler"]
 }
diff --git a/README.md b/README.md
index e8e3201..7b31fa2 100644
--- a/README.md
+++ b/README.md
@@ -3,3 +3,27 @@
 - [Web Serial API](https://developer.mozilla.org/en-US/docs/Web/API/Web_Serial_API)
 - UI components: [shadcn/ui](https://ui.shadcn.com/)
 - Icons: [tabler](https://tabler.io/icons)
+
+## Todo
+
+- [ ] Key-value pair line chart
+- [ ] Save config (`localStorage`)
+- [ ] Render control symbol (eg `\r\n`, `EOT`)
+- [ ] User script
+    - [ ] Tx data
+    - [ ] Rx data
+    - [ ] Save scripts
+    - [ ] Script editor (React Ace, CodeMirror)
+    - [ ] Built-in function
+        - [ ] CRC
+        - [ ] Modbus
+- [ ] Custom newline (`\n`, `\r\n`, timeout, mix)
+- [ ] Timing send
+- [ ] Hardware flow control
+- [ ] Tx & Rx bytes counter
+- [ ] Predefine command (eg AT cmd)
+- [ ] HEX send & display
+- [ ] ASCII control symbol keyboard
+- [ ] i18n
+- [ ] Terminal encode
+- [ ] Ring buffer