monthletmonthlet is a note app where you write and grow notes through AI chat. Version 1.2.1 was released on November 6, 2026.
In 1.2.1 you can switch the AI model from the chat box, and Markdown editing gained formatting buttons. Both come from requests readers sent in on this journal. This post covers the main features. The full list of changes is in the release notes.
Switching models from the chat box
The name of the model currently in use now appears at the bottom right of the chat input box, to the left of the send button. Clicking it opens a list of models, grouped by the AI providers you have set an API key for. Pick a model from the list and your next message is sent with it.
This lets you work mainly with one model and switch to a model from another AI provider depending on what you are doing. Switching here is the same selection as the one in the “AI” tab in settings. The model you chose last is also used in your next conversation. For AI providers you have not set a key for yet, choose “Use another provider (Settings → AI)” at the bottom of the list to open settings and add one.
Formatting buttons for Markdown editing
When you edit in “Markdown” mode, a row of formatting buttons now appears above the body. There are twelve: heading, bold, italic, strikethrough, bulleted list, numbered list, checklist, quote, code, link, horizontal rule, and table.
Select text and press the bold button to wrap it in bold syntax. Press it again to remove it. The heading button cycles through heading levels each time you press it. The table button lets you choose the number of rows and columns from a grid, and inserts a table skeleton.
⌘B and ⌘I (Ctrl+B and Ctrl+I on Windows) also apply bold and italic. Formatting applied with the buttons can be undone with ⌘Z (Ctrl+Z on Windows).
Performance improvements for large vaults
Vaults with a large number of notes (up to tens of thousands) now run faster. Links and the note map are built from the search index instead of reading every note. The sidebar no longer re-reads notes that have not changed.
Renaming or moving a folder no longer re-reads every note either. From the second launch onward, the search index is loaded rather than rebuilt. We will cover how much faster this is in a separate post.
Other changes
The main changes are:
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You can now ask the AI to copy a note to another folder. If you do not specify a destination folder, the AI asks you for one.
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Turning on “Spell check” in the “General” tab in settings shows a wavy underline under misspelled words. Right-click to choose a suggestion or “Add to dictionary”.
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Right-clicking a video in a note and choosing “Use as thumbnail” sets the frame at the current playback position as the note’s thumbnail.
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OFFSET is now available in spreadsheets. We also fixed slow recalculation with formulas that reference a whole column, such as “=SUM(A:A)”.
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Unfinished quick memos are now kept when you quit the app.
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Markdown import and export now preserve frontmatter keys written in Japanese, such as “ステータス”.
Try it out
monthlet runs on macOS (Apple Silicon) and Windows. The Windows version is available from the Microsoft Store. The features in this post are from 1.2.1 onward. Enter your own AI API key and all features are available.