ModalJazz

Features

ModalJazz has one aim: to make your music into beautiful, professional sheet music, with little effort.

With some practice, you type music fast. Or an AI agent types it for you. You see each change in the score as the agent works, so you can think about the music.

Key commands

  • Modes. Normal mode moves and edits. Insert mode types notes and pushes the music after the cursor forward. Replace mode types over the music. Visual mode selects a range or whole measures.
  • Letters are pitches. A letter gives the pitch from the key signature, in the octave nearest the previous note. + and _ move it an octave.
  • Sticky durations. Alt-1 to Alt-8 set the duration for the next notes. [ and ] make it shorter or longer.
  • Chords by interval. In Insert mode, 3 adds a third above the note and Shift-3 a third below.
  • Vim grammar. Counts, operators, and motions: dw, y$, 3w. . repeats the last change. Each action is one undo step.
  • Command line. : opens it, and Tab completes. For example :time 6/8, :key Eb, :transpose +M2.
  • Command palette. Cmd-Shift-P finds any action by name and shows its keyboard shortcut.
  • Tutorial. :tutor teaches the key commands, lesson by lesson. Each lesson checks the score that you typed.

Notation and engraving

  • Beams, stems, accidentals, dots, ties, slurs, tuplets, and grace notes.
  • Springs-and-rods spacing, line and page breaks, and justified systems.
  • Dynamics, hairpins, fingering, tempo marks, rehearsal marks, and text.
  • Repeats, endings, segno, coda, D.C., D.S., and Fine. Playback follows them.
  • Piano pedal marks, cross-staff notes, and up to four voices on a staff.
  • Measure numbers, multi-measure rests, and hidden rests.
  • Lyrics with hyphens and extender lines, more than one verse.
  • Chord symbols, slash notation, and other notehead shapes.
  • The Leland and Bravura music fonts. Paper sizes: Letter, A4, Tabloid, and A3.

Instruments and parts

  • Templates: piano, string orchestra, full orchestra, concert band, jazz band, choir, choir and piano, and woodwind quintet.
  • Add, remove, move, and rename instruments. Brackets and braces follow the instrument families.
  • Transposing instruments, with a switch to concert pitch.
  • Percussion: drum set and snare drum, with key commands for the drums in Insert mode.
  • Parts: :part violin shows one part with its own layout. Export all parts as PDF in one step.

Playback

  • Space plays from the cursor. Enter plays the event under the cursor.
  • Solo one hand or one part, mute parts, loop the selection, and change the speed.
  • The view can follow the playback.

Files

  • The native .mj format, with undo history kept on disk.
  • MusicXML import and export (.musicxml and .mxl), for other notation apps.
  • PDF and SVG export, and printing.
  • More than one score open at a time, in tabs or windows.

Work with an AI agent

ModalJazz is made for agents from the start. The app has a built-in MCP server, mj-mcp. An agent such as Claude Code, Claude Desktop, or another MCP client can read and change your scores.

  • Edits in the open score. With :set agent on, the agent changes the score in its window, and you see each change at once. The setting is off by default.
  • Undo. Each agent request is one undo step. u or Cmd-Z takes it back.
  • Only on your Mac. The app listens on a local socket that only your user can use. It has no network port.
  • Files too. When the app is closed, the agent changes the score files.
  • The tools. Read and write measures as compact score text, run : commands on a measure range, select, undo, and save.
  • Example requests. “Enter this PDF as a new piano score.” “Put measures 5-8 up an octave.” “Add a D.C. al Fine at the end of measure 16.”

Set up an agent, enter a PDF with an agent, or watch an agent enter a page.

Scripts and automation

  • The mj command. It opens a score, runs : commands, and saves or exports it, with no window: mj run prelude.mj ":5-8 transpose +P8".
  • Compact score text. A short, exact text form of the music, one line for each measure and staff: m5 P1.1: C5:q D5:q E5:h. mj read shows measures as text, and mj write writes text over measures.
  • One text for all. You, your scripts, and your agent use the same text and the same : commands.
  • Export. mj export writes PDF, SVG, MusicXML, and the native format.
  • Session replay. mj replay runs the key commands of a session from the app again.

See the mj command and the compact score text.

The view

  • Page view or a continuous scroll view.
  • A minimap of all pages.

System requirements

macOS 13 (Ventura) or later.